[HN Gopher] The world of pipe fittings
___________________________________________________________________
The world of pipe fittings
Author : naich
Score : 235 points
Date : 2022-11-27 10:32 UTC (12 hours ago)
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| turdherder wrote:
| Real life licensed and certified plumber here.
|
| Regarding the threads on common pipe fittings here in Cali: NPT
| threads are designed to be cut with a pitch and angle that are
| self sealing.
|
| Sealing compounds can assist in the lubrication of threads to
| easily tighten them up but should not be absolutely necessary.
|
| Imo it's an aid to assembly and disassembly and not always
| necessary depending upon the application. And in some
| applications it's forbidden
| jasonhansel wrote:
| Conveniently, of course, the US and Canada use NPT instead of
| BSP, the worldwide standard. Even if an NPT fitting and a BSP
| fitting are the same size, one won't screw into the other, since
| the threads have different shapes and are at different angles.
| djcapelis wrote:
| This guy wrote a whole article outlining how bad and unusable
| the British pipe standards are and you're surprised the two
| (ish) continents that don't use them are actually pretty happy
| with their standard and don't want the other?
|
| NPT has some flaws and complexities but generally while it's
| comprehensive conventions and practices mean that for specific
| types of plumbing you'll need some specific standard fittings
| and once you get used to them that's pretty much that. From
| gases to liquids. None of this "whoa someone decided to use a
| tapered one here" you don't get to chose what fitting you're
| feeling like that day, we have building codes and if it's a
| pipe in a wall carrying water than there's a convention (and
| likely building code) that tells you your pipe, fitting, and
| which way the threads should turn! (Generally in the broadest
| strokes: Explosive gases are reverse threaded. Everything else
| isn't.)
|
| Anyway we've been saying no to bad British ideas since 1776.
| Don't blame us outside the Americas the rest of you (and ISO)
| fell for it.
| dhosek wrote:
| Of the three aspects of home maintenance that are most common1:
| plumbing, electrical and carpentry, I feel most comfortable with
| plumbing. It seems nicely discrete in that you're generally
| putting together existing components without having to do much if
| any measuring and cutting. That said, I'm moving into a new house
| where I've got a handful of carpentry projects that will
| definitely stretch my abilities in that arena.
|
| [?]
|
| 1. In my experience, I suppose, one could perhaps add
| concrete/masonry and may be something with dirt?
| agsamek wrote:
| This article doesn't touch much about why plumbing is hard. I'm
| from Poland so I'm not only IT but also a plumber ;)
|
| Plumbing is hard because it is not forgiving. It's as binary as
| IT except you can learn the outcome with some delay, once you
| learnt about a damage caused by a leak. Either you do a pressure
| tests right or repair can be expensive. And bugfixing is always
| tricky.
|
| Water also goes down whether you like it or not. Think about all
| possible leaks inside the shower cabin. Or what is even more
| impressive that under a pressure the water goes everywhere
| possible.
|
| Plumbing is similar to electrical engineering, except it usually
| doesn't kill immidiately (though working with gas is tricky
| anyway) but requires similar strict mental model to do right.
|
| And when you see a plumber it seems like this person is just a
| physical worker. So work status misconception must be leveled
| with money...
| PaulHoule wrote:
| My complaint is that plumbers frequently do poor work for the
| money.
|
| We had some come and install an instant water heater and they
| cut an ugly hole in the side of the house without much thought.
|
| At one office I worked in they called Roto-Rooter (a non-union
| franchise that is likely to wreck your pipes and require a call
| to the union plumbers afterwards) who claimed that we'd flushed
| a condom down the drain (very hard to believe) and wrecked the
| pipes so we had to call the union plumber.
|
| Another time the sink wasn't running so we called the union
| plumbers, they unscrewed the aerator from the faucet, saw some
| crud come out and the water run and left in triumph, sure of
| their ability to outthink a group of mere computer nerds.
|
| Us computer nerds were sitting at the faucet immediately after
| that, running it and talking about it. The now aerator free
| faucet clogged up again within 2 minutes of the plumbers
| leaving.
| nkrisc wrote:
| > My complaint is that plumbers frequently do poor work for
| the money.
|
| Considering the quality of many expensive website and
| software implementations I've been required to use throughout
| the years at various jobs, this problem is not unique to
| plumbers.
| agsamek wrote:
| > My complaint is that plumbers frequently do poor work for
| the money.
|
| Hehe - now you can feel like an IT customer. I think most
| people feel the same about IT but the domain is just more
| wide and prone to excuses.
| pasquinelli wrote:
| people feel that way about stuff they have to pay for,
| generally.
| PaulHoule wrote:
| No, I've never felt that way about a union electrician or
| generic handymen.
| throw0101c wrote:
| > _This article doesn 't touch much about why plumbing is hard.
| I'm from Poland so I'm not only IT but also a plumber ;)_
|
| I'm guessing that is a reference to Omid Djalili sketches about
| Polish plumbers:
|
| * https://www.youtube.com/watch?v=K85ZtXnMxbM
|
| * https://www.youtube.com/watch?v=P8mjzu0Runo&t=1m
|
| * https://www.youtube.com/watch?v=_FM9Ps6cW9U
|
| * https://en.wikipedia.org/wiki/Omid_Djalili
| lajosbacs wrote:
| It's a stereotype across the whole Europe, even Poland takes
| advantage of it https://en.wikipedia.org/wiki/Polish_plumber#
| /media/File:Pol...
| agsamek wrote:
| Thanks for sharing. This was exactly what I was referring
| to. Also youtube links from the UK are nice, shame you are
| out of EU for the time being :)))
|
| Anyway - I just added a valve regulation to our kitchen
| floor heating this weekend, so it was not only joking :)
| lajosbacs wrote:
| I also found the UK vids amusing (am not a Pole) -- kind
| of how to make fun of a stereotype in a positive way.
| iancmceachern wrote:
| Yes, and it's even less forgiving when it's a gas, or worse a
| flammable gas, or 3000 psi hydraulic fluid.
| georgeoliver wrote:
| I had a funny experience a week ago. One night working on a
| hobby web project it took me three or four hours to debug
| something, I finally got to bed around midnight thinking "boy,
| programming is hard".
|
| The next day at work we had to find a broken heat wire in a
| tiled bathroom floor, running 1000 volts through the wires to
| try to fuse the broken wire, then heating the floor up and
| searching with heat-sensitive paper overlays for the likely
| broken spot, then breaking the tile with a hammer and digging
| the wire out of the mortar bed. After we found it I thought,
| "I'd rather hunt software bugs".
| sokoloff wrote:
| Does a thermal imaging camera not work for the finding task?
| That seems like it would be faster, more certain, and less
| aggravation all around.
| georgeoliver wrote:
| Good question, I don't know. The technician on site didn't
| have one. I guessing the camera would be faster, but the
| result image about the same. The nice thing about the paper
| is you easily can check multiple spots at once, so it's
| faster to divide down to the problem area.
| CamperBob2 wrote:
| Time-domain reflectometry. To Google it is to love it.
| iancmceachern wrote:
| I once had to jackhammer a 4 foot wide, 26 foot long, 4 foot
| deep trench in my basement to replace the sanitary sewer in
| my house. It was old terracotta pipe and had tree roots
| growing into it and eventually blocked the flow. It was doing
| that that helped me be so thankful to have an office job. I
| also had to lug all the rubble upstairs in 5 gallon buckets.
| swayvil wrote:
| Given the choice, I love pex and those compression-bands that you
| put on with the special pliers. Pex got flex.
|
| For drains, pvc of course.
|
| Given run-of-the-mill refurbby waterline junk with plain ol
| copper, I like that brass kind of compression with the little
| sleeve.
|
| Don't trust sharkbite. Am a mediocre sweater.
|
| For gas, threaded with that pipe goo works surprisingly well.
| Haven't fucked it up yet.
|
| I wonder if you can use pex with gas
| ssl232 wrote:
| You do your own gas work? I'm in the UK and I'm pretty sure you
| basically cannot legally touch gas fittings unless you're a
| qualified plumber.
| iancmceachern wrote:
| Agreed on the compression fittings over the sharkbite stuff.
| PaulHoule wrote:
| When I had to do some plumbing I found that everything was
| undocumented. One source would tell you to refer to the
| documentation published by the manufacturer of the fitting, which
| is of course impossible to find.
| jesusofnazarath wrote:
| VLM wrote:
| The story misses some points.
|
| The first issue is pipes are used for a lot more than pressurized
| drinking water, and for compressed gases there's various
| standards so you don't accidentally connect your acetylene tank
| to your argon regulator and vice versa. Depending on local
| building codes, you have to work really hard in the USA to cross
| connect your natgas to your water supply, etc. For a home
| handyman this seems laughable but for giant construction projects
| at industrial sites you will inevitably see insane stuff sooner
| or later where roughed in water lines get accidentally connected
| to compressed air and stuff like that. I personally saw a PVC
| convenience pipe roughed in for ethernet cable get connected to
| sewer vent.
|
| The second issue, related to the above, is NPT relies on thread
| deformation so the pros use pipe dope and the amateurs use teflon
| tape that contaminates everything, so you technically "can" use
| NPT for diesel or hydraulic but usually building codes and/or
| OSHA prevent such nonsense. Also thread deformation means every
| time you reuse a NPT its looser and leakier. Very slow leaking
| threads are not an issue for compressed air, so black iron pipe
| is common for industrial compressed air because who cares if
| 0.01% leaks out, but for flammable contamination sensitive stuff
| its a big issue. If 0.01% of your compressed air leaks out above
| a food prep assembly line nobody cares but if 0.01% of your
| hydraulic fluid leaks out into the food, then its a big food
| safety mess. The point is that most of this technology is being
| used outside its original use case, most NPT threads are not
| holding back compressed air, but crazy people are trying to use
| that tech to push natgas around or diesel or whatever and due to
| "tradition" and "codes" we are stuck with it. So the argument
| that NPT is shit so nobody should use it is pointless because its
| "really intended for" compressed air and is great for that, super
| cheap, easy to use, reliable enough, etc, so pointing out that
| its not optimal for car brakes is both true and also not useful
| "in practice".
|
| Another comedy about threads: You can buy pipe dope to
| professionally seal NPT threads for air, natgas, car brakes, and
| water, but those pipe dopes are not the same, and you can cause
| quite a bit of trouble if you use air dope on natgas for example.
| thedanbob wrote:
| I had a major plumbing problem some time ago (leak in the house's
| main line) and paid a plumber way too much to dig a hole and fix
| it. I of course wasn't about to pay him to fill the hole back up,
| and while it was open I took a good look. That's when I
| discovered PEX. PEX is wonderful: easy to work with, inexpensive,
| simple to fix if you screw something up. I wish all plumbing was
| PEX.
|
| I briefly installed an NPT flow meter (that was probably actually
| BSP) in the line. I can confirm that the PEX-to-NPT fittings
| leaked until I used a whole roll of PTFE tape and a mountain
| gorilla. Eventually the cheap flow meter started leaking from the
| casing itself so I ripped it out and replaced it with beautiful
| PEX.
| iancmceachern wrote:
| Pex is awesome, I replaced my entire house with it, I couldn't
| have done it myself otherwise and had a great result.
| toss1 wrote:
| Can confirm - also started using PEX recently, and it is
| fantastic - wouldn't go back for anything! Straightforward,
| solid, more resistant to freezing (tho I still drain/blow out
| the outside lines in winter). I've even had zero problems with
| the PEX-copper fittings; I generally just attach straight onto
| a cut pipe rather than an NPT fitting, so that may account for
| my different experience.
|
| I've run a few new lines in the house, and also new hose
| faucets outside. Looking at using it for both vacuum and
| compressed air lines in the shop.
| VLM wrote:
| There are two problems with PEX in the shop, one real one
| joke.
|
| The joke one is PVC + UV = shrapnel, and frankly given enough
| time and vibration PVC doesn't need UV to shatter, so old
| timers hearing you're using plastic in the shop will freak
| out. (edited for those who don't get the joke: Pex will
| definitely split or crack under UV but AFAIK never shatters,
| so using PVC is a major OSHA violation but using unprotected
| Pex is mostly safe although maybe economically unwise)
|
| The real problem is the melting point is unimpressive and
| you're like one lathe chip away from an air leak. Not
| catastrophic but annoying. Murphy's law is air leaks only
| happen when you don't have time to slap a new fitting on, or
| when your collection of fittings is empty/missing and the
| store closed five minutes ago.
| toss1 wrote:
| Thank you!! Very helpful tips, I appreciate it
| scotty79 wrote:
| There is a pex variant which consists of aluminium pipe
| with plastic layers on the inside and outside. This
| should combat low melting point of the plastic
| beerandt wrote:
| Locally, we also have problems with rodents chewing threw
| unprotected pex. Probably because we rarely freeze, and
| unprotected really means completely unprotected.
| [deleted]
| ssl232 wrote:
| I've not done any major replumbing yet but I've been watching
| Matt Risinger [1] on YouTube for a few months and have quickly
| become a PEX fanboi. He's a home builder based in Texas and
| uses PEX for basically every job. There are some videos on his
| channel comparing different types of PEX and PEX against other
| systems.
|
| [1] https://www.youtube.com/@buildshow
| latchkey wrote:
| We started with welded joints, then moved to threaded (and
| every variation in between of that). I kind of wonder if PEX
| will be deprecated some day by something even better. We are
| going to end up with yet another standard that PEX has to
| interface with. Feels like an xkcd... https://xkcd.com/927/
| jasonwatkinspdx wrote:
| Came here to also plug PEX. A friend used it for his remodel,
| did most of the work himself, and set everything up so all the
| lines come down to a sort of "switchboard" panel in his
| basement, so that as he did more remodeling work in the future
| he could disconnect individual loops trivially. It just makes
| so much sense and is so easy vs copper pipe.
|
| Amusingly he told me one of the plumbers he did get a bid from
| said something like "well all PEX does is save you time and
| money" like it was a bad thing lol.
| msrenee wrote:
| It breaks down pretty quickly when exposed to light,
| chlorine, and excessive heat. It's also very easy to damage.
| A kid being an idiot or rats and mice gnawing on everything
| like they do and you've got a heck of a leak that hopefully
| is caught quickly.
|
| Seems like there's lots of situations where it's a good
| choice and lots of situations where it's not.
| nemo44x wrote:
| It's also super easy and affordable to run extra lines that
| aren't being used for future use. For instance, it might be
| you want to run a circulator across all your taps, but not
| today.
|
| You can in many cases snake it as well.
| bilsbie wrote:
| What's the one that leaks and you're supposed to replace?
| schemescape wrote:
| Probably polybutylene:
| https://en.m.wikipedia.org/wiki/Polybutylene
| tharkun__ wrote:
| Kitec: http://kitecsettlement.com/
| luxuryballs wrote:
| I thought they were paid so much because plumbing is gross and
| often just a huge pain.
| iancmceachern wrote:
| Exactly, I do the simple stuff myself and only call a plumber
| when it involves crawling around in a spider infested crawl
| space, working with poop, or similar things I am willing to oay
| someone to do.
| playingalong wrote:
| What would you call this writing style (which I like a lot).
| Ironic? Any more specific name?
| mongol wrote:
| Gonzo-inspired?
| lelandfe wrote:
| Disgruntled Brit? I read most of it in the tone of David
| Mitchell: https://www.youtube.com/watch?v=Bz2-49q6DOI
| OJFord wrote:
| 'Annoying', personally.
|
| Seriously though, sort of a monologue? Or I'd describe it (not
| a single word) as spoken English taken to paper, in an oral
| style, or something.
| digitalsushi wrote:
| conversational-familiar
| hirundo wrote:
| "When buying male fittings, it's best to always get tapered ones
| so they fit in either."
|
| I tried that with a shop compressed air system and got lot of
| leaks, hissing, and the compressor turning on frequently. And I
| never did get the system not to hiss somewhere, so I can
| sympathize and ditto this rant. Even when using matching
| fittings, with gobs of tape and/or dope, and enough force to
| destroy multiple fittings, it leaks. I'd pay a plumber well to
| teach me some of those mystic arts, if I could find one in my
| plumber-free rural area.
| loeg wrote:
| Air hose standards are also annoying and differ from plumbing.
|
| https://toolguyd.com/quick-guide-to-air-line-couplers-plugs/
| katmannthree wrote:
| The quick connect side yes, the threaded side is a standard
| NPT (if you're in the US) which you treat the same way you
| would any other NPT connection.
| katmannthree wrote:
| If you're talking about quick connects, they'll always leak a
| bit.
|
| The threaded fittings however are a different story. Assuming
| you didn't use stainless steel on stainless steel fittings [0]:
|
| * You can find the leaks by spraying soapy water on suspect
| connections and looking for bubbles (wash off and dry with
| clean water afterwards unless you want some serious corrosion).
| You can also buy a jar of noncorrosive propylene glycol based
| leak check fluid at your local hardware store for somewhere
| around $10, which is a strictly better option although it's a
| bit harder to clean off.
|
| * Undo the connection and throw away every fitting you can
| replace (you generally should not reuse NPT threaded
| connections unless you know what you're doing). Clean all
| fittings until they look brand new and with no visible debris
| on/in the threads.
|
| * Watch some videos [1] and remake the connection using the
| proper amount of tape and sealant and appropriate torque [2].
| Only tighten the fitting. If you loosen it even a bit during
| the process, undo it completely. Clean both sides, reapply tape
| and dope, and try again. Let the sealant set ~24h and retest.
|
| [0]: Stainless steel pipe connections are a special case
| because they tend to cold weld before they're fully tightened.
| There are ways to mitigate that but the short answer is don't
| use them if you don't already know how.
|
| [1]: https://www.youtube.com/watch?v=whw9ApDJpJo
|
| [2]: NPT connections really shouldn't be torqued (you instead
| use turns from hand-tight for properly cut threads) but if
| you're having trouble find a torque chart for your fitting
| material (copper, brass, steel, etc) and follow that.
| synecdoche wrote:
| In one of the larger companies in Sweden in the third largest
| city Malmo that sell to both other companies and consumers none
| of the staff knew what I was talking about when I mentioned that
| BSP and NPT are different. Neither people on the floor nor people
| answering the phone. These were what appeared to be experienced
| plumbers. It's amazing.
| weare138 wrote:
| That's funny. I literally just finished installing a new kitchen
| sink and faucet at home. Holy crap was it a pain in the ass.
| victor9000 wrote:
| What was tricky about it? Having never done it, it seems
| somewhat straight forward in my mind.
| blincoln wrote:
| Sinks are one of the few areas that I don't think one can get
| out of using threaded connections on the supply lines
| (haven't seen push-to-connect for that last leg yet). A lot
| of them use NPT threads, and NPT is very easy to put together
| in a way that will have a slow leak. Even a single drop every
| few minutes can cause big problems if left unattended for
| long enough. Also, a lot of the connections are in locations
| that are a headache to reach, even with a basin wrench.
|
| Getting a good seal on a sink drain can be a little tricky
| the first time too.
| sokoloff wrote:
| The sink supply connections (usually from a shutoff valve)
| are compression threads (a parallel/straight thread).
|
| If the valve itself is threaded on, _that inlet_ might be
| NPT (or might be compression), but the valve outlet will be
| compression, which uses a tapered ferrule to provide the
| seal and straight threads.
| mindslight wrote:
| The faucets I've seen are generally NPS where the supply
| lines attach to the faucet, often with the retaining nuts
| (or whatever they're called) using the same threads and
| going on first.
|
| To answer GGP's question, what's difficult about faucets
| is getting up behind the sink, with your back straddling
| the corner of the cabinet, reaching up with some sort of
| basin wrench that inevitably won't grip those bespoke
| retaining nuts well. Especially removing the old faucet
| where the retaining nuts are a bit seized.
| weare138 wrote:
| The process itself is straight forward but I had to work in a
| really tight space under the sink. That was really what made
| it a pain in the ass. I had to lay on my back and cram myself
| underneath the sink in the cabinet to reach everything plus
| I'm a 6' tall goon so that definitely wasn't helping either.
| You're just stuck in an awkward and uncomfortable position
| most of the time.
| ssl232 wrote:
| Same experience installing a dishwasher. Inside a small
| cavity accessible only by climbing over my new dishwasher
| and avoiding the existing washing machine, crouching using
| leg muscles I rarely ever use, with the only light coming
| from a torch, on flooring made damp from dripping pipes
| that I hadn't tightened enough, arms getting sore from
| lifting them above my shoulders for extended periods, I
| understood why plumbers get paid what they get paid.
| throwawayacc4 wrote:
| This article sucks. Lots of bad info from an inexperienced
| plumber.
|
| How the US military, nuclear power plants, and plumbers worth
| their weight in salt do fittings: 3-4 times around the (male)
| fitting with PTFE tape, then a light amount of pipe dope on top
| of the PTFE tape.
|
| Also, DO NOT buy the cheap PTFE tape as suggest. Buy the milspec
| tape. Your big box store will have both and you'll know where
| that money (a couple dollars at most) went.
| CamperBob2 wrote:
| _3-4 times around the (male) fitting with PTFE tape, then a
| light amount of pipe dope on top of the PTFE tape._
|
| That doesn't sound like a good idea at all. The whole idea
| behind PTFE (aka Teflon) is that it reduces friction because
| nothing, including pipe dope, sticks to it. What value does the
| pipe dope add to a properly-wrapped fitting?
| Severian wrote:
| Milspec, lol. Doesn't that normally equal as cheap as they can
| get away with?
|
| There is a high-density thread sealing PTFE tape that works a
| bit better than the el' cheapo generic white stuff (although
| it's usually white too). Anything marked as such should be
| sufficient unless you are working on an oil rig or nuclear
| reactor.
|
| EDIT: Unless the package has MIL-T-27730 on the tape, labeling
| it milspec has no meaning.
| kevin_thibedeau wrote:
| > Milspec, lol. Doesn't that normally equal as cheap as they
| can get away with?
|
| It means a product meets stringent requirements that can't be
| cheated on.
| mildchalupa wrote:
| The Teflon tape is only to be used as a friction modifier as NPT
| and other tapered threads seal on the threads. Reduced friction
| means that you can get enough load to deform the metal threads
| and create a seal. Be careful to not add tape to the first 2
| threads as small pieces of Teflon tape can break off and get
| stuck into valves and things within appliances causing them to
| leak. There is nothing wrong with pipe dope and I find it to be
| superior though messy.
|
| Annoyance for those in the states: Big box stores used to
| advertise fittings as NPT (National pipe thread). NPT being an
| ANSI spec. They seem to have switched to MIP and FIP for Male
| Iron Pipe and Female Iron Pipe. These are NPT as well but with a
| new name? Perhaps they are looking to avoid holding themselves to
| the spec?
|
| Lead content in brass drinking water rated piping and fittings
| are being phazed out for obvious reasons. New low lead brass is
| stronger and does not deform as easily as the older leaded brass
| fittings. The result is that some fittings are now more difficult
| to tighten untill leak free.
|
| Pex and crimped copper fittings are not without there own issues.
| Relying on an o-ring with a 30 year shelf life is problematic
| when the pipe is behind drywall.
|
| Perhaps one day we will get laser welded copper fittings.
| loeg wrote:
| I've seen FNPT and MNPT but not FIP/MIP.
| frosted-flakes wrote:
| Crimped PEX fittings do not use o-rings.
| digitalsushi wrote:
| it's really easy to go crazy at a box store and get boiler
| fittings for a garden project. read the labels for lead
| content!
| imglorp wrote:
| > Relying on an o-ring
|
| Another category is Shark Bite, a simple push-on tech that is
| almost homeowner proof. All you need for many jobs is a cutter,
| some sandpaper, and the fitting: no pro tools, no torch. There
| are tight joist spaces the new copper crimper won't fit and
| overhead soldering is fraught, which you can sharkbite in 2
| minutes.
|
| Back to O-rings, I do wonder about the lifetime of the seals in
| there though.
| cf100clunk wrote:
| If Shark Bite products are not available there is also the
| Waterline Push-N-Connect line of similar products for
| homeowners:
|
| https://waterlineproducts.com/products/push-fit-fittings-
| and...
|
| There are other similar products from different companies.
| belorn wrote:
| Depend on size and material of the o-ring. A o-ring is a
| flexible material that under pressure will bend in order to
| fit a space. Under high pressure the material might intrude
| out slowly, if you repeatably bend it it might snap, and as
| with many flexible materials it may go brittle and crack if
| exposed to changes in temperature or moisture.
| jkqwzsoo wrote:
| In case anyone from the US reads this, BSPP and BSPT fittings are
| rare and incredibly frustrating here, as our NPT (National Pipe
| Taper) threads are different and the selection of BSP(P/T)
| fittings is extremely poor in comparison.
|
| Also, I work with NPT fittings quite a lot:
|
| > For what it's worth, I tightly wrap the tape 10 times round the
| male thread and get an enraged mountain gorilla to tighten it up.
|
| This is a WTF NO!!! for NPT and I'll assume a WTF NO!!! for BSPT
| as well. You need about 1.5 wraps of PTFE tape to seal a fitting.
| Any more is wasteful and asking for leaks (or damage, if you're
| using plastic fittings). It helps if you use the correct tape
| width for the fittings (1/4", 1/2", and 1" for me) and develop a
| wrapping method that keeps the tape under tension at all time and
| in such a direction that threading it into the fitting doesn't
| unwrap the tape.
|
| Also, in my experience, when someone inexperienced first learns
| what pipe tape is, they try to apply it to everything. 20 wraps
| around a tapered pipe? Wrap a Swagelok fitting? Try to make a
| butt joint or an adapter for two pieces of plastic tubing? I've
| seen it all.
| PaulDavisThe1st wrote:
| Pipe dope FTW.
| jnellis wrote:
| Indeed. If your threads are new you're not supposed to use
| any teflon tape, you use pipe dope. Teflon tape is for worn
| threads when you are out of pipe dope.
| sokoloff wrote:
| I use a minimum of 4 wraps and usually 5 or 6 wraps on black
| pipe in the 3/4"-2" range. 2 wraps might be enough for nice
| clean plastic or brass threads in the 1/2" or less range, but
| larger steel fittings need more PTFE tape.
| kortex wrote:
| > You need about 1.5 wraps of PTFE tape to seal a fitting.
|
| Not a pipe fitter, but I've done a lot of plumbing on a huge
| variety of systems (sinks, drains, air lines, HPLCs and other
| chemistry equipment, bioreactors, RO systems, potato cannons).
| I have found through experience that the thick PTFE tape
| (usually grey or yellow) is almost always superior to the thin
| tape. I use 2-3 wraps of that and that seems to be ideal.
|
| Thick tape is also a lot easier to remove than the thin PTFE if
| you have to reinstall (you aren't supposed to re-use tape if
| you unscrew it).
| kennend3 wrote:
| As someone who is NOT a pipe fitter but lived with one for many
| years.. It was odd reading this and I'm glad someone like you
| responded to correct things.
|
| > For what it's worth, I tightly wrap the tape 10 times round
| the male thread and get an enraged mountain gorilla to tighten
| it up.
|
| Again, not a pipe fitter but this just screams "WRONG". If
| someone needs to use that much force to tighten it up, one can
| only assume that the pipe is now so full of tape it simply
| doesn't fit?
|
| My roommate had a "unlimited BTU" gas fitter license (Canada
| Class "A") and this for a living and preferred "pipe dope"
|
| "Pipe dope is generally stronger seal than Teflon tape, which
| is why plumbers and other professionals use it rather than tape
| for seals that are permanent."
| rsync wrote:
| "My roommate had a "unlimited BTU" gas fitter license (Canada
| Class "A") and this for a living and preferred "pipe dope""
|
| I do this kind of thing _a lot_ as we own and maintain our
| own water plant. My preferred sealant is the yellow PTFE tape
| that is used for natural gas.
|
| It is quite a bit thicker than the white tape, it sticks to
| threads better and it is easier to work with, in terms of
| manual dexterity.
|
| I never use the white tape for anything.
|
| I don't like pipe dope at all and I only use it for large
| fittings that are going to be buried or inaccessible.
|
| ALSO, helpful hint: If you are mixing plastic pipe (like
| schedule 40/80) and metal pipe, always have metal female
| couplings and plastic male couplings. A metal male going into
| a plastic female is one tighten away from cracking the
| plastic.
| couchand wrote:
| I've seen people suggest that white tape should only be
| 1.5-2 but yellow should be 5 or more, do you have thoughts
| on that? Is there a difference in usage or is it the same
| overuse pattern on both?
| amluto wrote:
| > ALSO, helpful hint: If you are mixing plastic pipe (like
| schedule 40/80) and metal pipe, always have metal female
| couplings and plastic male couplings. A metal male going
| into a plastic female is one tighten away from cracking the
| plastic.
|
| Or buy transition fittings or "special reinforced"
| fittings. Or, if you trust them, use push-to-connect
| fittings -- SharkBite, John Guest, ProLock, etc. (ProLock
| appears to be a John Guest product that is also sold by
| SharkBite.)
|
| I've seen plenty of female plastic threaded fittings break
| even when connected to male plastic threaded fittings.
| They're just not that strong under circumferential tension.
| balls187 wrote:
| > Also, in my experience, when someone inexperienced first
| learns what pipe tape is, they try to apply it to everything.
|
| That's me. Whoops.
| VLM wrote:
| Tape causes massive contamination problems with fuel and
| hydraulic systems.
|
| Its not that the Teflon reacts with hyd oil, its that the
| inevitably little tiny bits of stuff physically jam/ruin
| seals and clog nozzles.
| culopatin wrote:
| But only if you put the tape over the edge. I usually leave
| the first 2 threads uncovered, why would it fall into the
| stream if you don't cover the tip of the thread with it?
| kevin_thibedeau wrote:
| When you open up the joint, bits are left behind in the
| female half. Then they get pushed in when it's resealed.
| VLM wrote:
| The most installed/removed NPT thread will leak the most
| thus have the most tape added and the scraping of
| installation/removal will guarantee teflon contamination
| of the system eventually.
|
| You are also correct in that something installed one time
| for the lifetime of the system, especially with some care
| and attention to cleanliness, is almost certainly OK.
| rdl wrote:
| Ugh, I applied it to _PVC_ pipe, which made it leak, sigh.
| [deleted]
| VincentEvans wrote:
| There's no problem applying it to a threaded connection in
| PVC. Unless you mean that you've figured out a way to apply
| to a fitting that's meant to be glued? In that case I
| commend your abundant creativity.
| rdl wrote:
| My experience is that even one wrap of PTFE tape on
| threaded PVC causes it to loosen and then leak, and it's
| recommended by youtube/google to not use it. (Some say
| sealant is ok).
| hilbert42 wrote:
| _" You need about 1.5 wraps of PTFE tape to seal a fitting. Any
| more is wasteful and asking for leaks"_
|
| I would have thought this obvious and it's essentially my
| experience (and I'm definitely not a plumber). However, I've
| found that more PTFE tape is needed on old or worn fittings or
| on ones that have damaged or badly cut threads--or when mating
| same sized pipes/fittings but each with different threads (yes,
| that's a desperate brute-force move in an emergency but I've
| had to force such matings on more than one occasion). In these
| circumstances, I'll use two or three turns or more often by
| trial and error--and this changes somewhat depending on whether
| I'm using thinner white PTFE tape or the thicker pink one.
|
| Of course--not being plumber--it often happens that when I
| urgently need PTFE tape I cannot find it (it having been filed
| in some obscure place that I've forgotten about--even though I
| keep a reasonable stock of it), it's then I fall back to the
| good old combination of Hessian/burlap jute-type rope (of which
| there is always some lying around in my workshop) and linseed
| oil based paint. It's messy and much less convenient
| combination than PTFE tape but it still works wonderfully well.
| Moreover, it's more tolerant of the amount applied as the
| linseed oil actually binds to the pipe surface as opposed to
| the more 'mechanical' bond of the PTFE.
| SaintGhurka wrote:
| "combination of Hessian/burlap jute-type rope (of which there
| is always some lying around in my workshop) and linseed oil
| based paint."
|
| Could you explain that? How do you seal pipe fittings with
| rope?
|
| Edit: found an explanation. TIL that you can use the fibers
| just like tape and wrap the threads.
| hilbert42 wrote:
| Perhaps if I'd used the proper name what I said may have
| been clearer. The correct name is hemp rope or plumber's
| rope but I don't often have that around (not being a
| plumber) so I use the next best thing available Hessian
| fabric or its rope equivalent).
|
| Here are some photos:
| https://www.bunnings.com.au/enduraseal-1m-plumbers-
| hemp_p012...
|
| https://waropes.com.au/twines/plumbers-hemp/
|
| You wrap the hemp fibers around the threads that have been
| brushed with linseed oil paint then apply a little more
| paint to the hemp and then mate the couplings together.
| This sealing technique has been around at least for several
| hundred years if not longer.
| throwaway294566 wrote:
| You don't need oil, just rope works as well. Every DIY
| store (at least over here) has loose manila fibre for that
| purpose. Wrap into the thread, screw it together, done. The
| not-so-nice problem: It might leak at first. The nice
| feature: The fibres will soak up water (thats why oil is
| actually counterproductive), swell up and make a tight fit
| after half an hour or so. You can even readjust the angle
| (other than with PTFE tape), it'll just drip for another
| half hour.
| hilbert42 wrote:
| Right, there are multiple variations but they generally
| work in skilled hands although I learned from plumbers
| who always used oil (although using oil was always an
| imperative with gas pipes). Using oil usually negates the
| initial leaking whilst waiting for the hemp to dampen and
| swell.
|
| _Edit: I agree that using oil is counterproductive with
| water pipes--initially at least. I was taught by both
| plumbers and my father (who wasn 't a plumber but a
| mechanical engineer who worked on power station boilers)
| that using oil is better in the long run as it prevents
| the hemp from rotting and thus premature failure of the
| seal. Moreover, using one oil-based method means that a
| plumber cannot get confused and leave oil off gas
| connections where it's essential.
|
| (I'd add that when referring to oil I'm specifically
| referring to linseed oil (even though I've seen some
| plumbers inappropriately use engine oil) because it
| slowly polymerizes and hardens even in the absence of
| air. This adds to the seal's effectiveness and further
| protects the hemp.)_
| jcims wrote:
| >Of course--not being plumber--it often happens that when I
| urgently need PTFE tape I cannot find it
|
| Ahh, young padawan, the way of the elder is to buy a roll
| every time you have a project to do until you have achieved
| saturation...where there is a lightly used roll of teflon
| tape in every drawer and on every surface of your workshop
| and garage.
| sokoloff wrote:
| I unlocked an uncommon DIY achievement last month: I
| finished an entire 119 foot roll of PTFE tape.
| jcims wrote:
| That's beyond 'uncommon', you should get a trophy.
| hilbert42 wrote:
| One has to ask 'finished it doing what'.
| bluGill wrote:
| Some sort of mummy costume party i'm sure
| andylynch wrote:
| This is the way. It's also cheap enough that buying a dozen
| rolls upfront is less effort!
| semireg wrote:
| I just bought 24x 6" stainless steel rulers because every
| time I'd reach for one it'd be across the room at a
| different desk. Now I can capture a dozen at a time in
| their remote location for rehoming. Problem solved.
|
| Also on my list of buy too many so I'm never left without:
| sharpies, microfiber cloths, jumper cables, rice (carbs),
| frozen sliced sourdough (fancy carbs), pocketable
| protein/energy bars.
| hilbert42 wrote:
| Ha! I'm no longer a Padawan so, like you, I'm well
| acquainted with the practice of spreading things around to
| the point of saturation.
|
| It's not only PTFE tape that I spread around in copious
| quantities, other notables on the list are screwdrivers (of
| various sizes and types), superglue tubes (they go off with
| age anyway), propelling pencil leads, keys, USB and
| computer cables, USB pen drives, computer mice, adhesive
| tape, remote controls and any number of useful things.
|
| The trouble is these supposedly inanimate objects come to
| life in the middle of the night and conspire not to be
| available when I most need them. Then the moment I've made
| do by jerry-built means they suddenly reappear! ;-)
| dtgriscom wrote:
| When I was a kid, my mom's theory on pencil purchasing
| was that if she bought enough, the house would be so
| saturated that you could shake a curtain and a pencil
| would fall out.
| hilbert42 wrote:
| Hum... Clearly, I'm not alone. That's at least some
| comfort.
| geerlingguy wrote:
| Almost every night I pick up 3-5 pencils around the main
| living area at our house. Somehow there are always dozens
| of pencils around, but finding one with a working eraser
| on the end is as rare as finding a unicorn.
| devnullbrain wrote:
| The mistake-making side is much larger than the mistake-
| fixing side. This is a display of great, foolish
| optimism.
| mindslight wrote:
| That's only the way of the middle-aged. If you do it with
| just PTFE tape you'll be fine, but if you do it with all
| similar sundries, then you'll be oversaturated and once
| again won't be able to find anything without pawing through
| piles.
| hilbert42 wrote:
| Right, see my reply to _jcims_ but that 's not all of
| matter. One could suppose I'm going senile and perhaps
| that's true but the fact is that I've been losing stuff
| like this since before I was a teenager.
|
| I've figured out the problem: my mind is thinking about
| all sorts of seemingly important stuff all the time but
| which in fact is mostly garbage, so my subconscious mind
| handles what my conscious mind consideres as procedural
| or unimportant. As my conscious and subconscious minds
| aren't on speaking terms sufficient for my liking I often
| end up with the problem of lost stuff.
|
| If I consciously tell myself where I've put something
| then I very rarely forget where it is. The trouble is I
| don't remind myself to make note often enough.
| mindslight wrote:
| My own working model is one of complexity building up
| over time. You can handle it fine as long as you don't
| have many fields of endeavor, you have plenty of time to
| periodically focus on them, keep the stuff organized, can
| fully finish a project and button it up, etc. But then
| things happen where you're forced to clear out your
| mental cache, or even screw up your organization/storage
| system for whatever, and it comes crashing down. Then all
| the complexity you were managing gets in your way, and
| the problem snowballs unless you regain some bandwidth
| and take steps to mitigate the decay.
| hilbert42 wrote:
| Right, that makes sense. And my explanation is more
| complex than I could detail in my comment.
|
| I know I have too many diverse interests--fields of
| endeavor to quote you--and the older I get the more of
| them I accumulate. On the one hand having many interests
| is very useful because it allows me to see and understand
| common ideas or threads across quite disparate and
| diverse subjects that otherwise would not have been
| obvious but the matter of administration becomes a
| significant problem. Often I've little time to deal with
| prosaic matters so the mundane is often left to itself
| (disorder accumulates).
|
| That said, I'm instinctively an orderly and tidy person,
| as I like to say _' there's a place for everything and
| everything in its place'._ I hate mess and disorder but
| that doesn't mean that I don't experience it--I do so
| often for reasons that you mention. However, when
| entropy/disorder around me reaches a certain
| 'sensibility' threshold I'm triggered to have an almighty
| cleanup much to the chagrin of others around who have a
| more relaxed view of disorder.
|
| Nevertheless, I'm not obsessive about it, sometimes I
| amaze myself at the level of disorder I'll tolerate.
| (Reordering things is boring and distracts me from my
| interests despite the fact that I'm competent and
| thorough about it. Essentially, the more preoccupied I am
| with something the higher my toleration for mess and
| disorder becomes).
| Geezus-42 wrote:
| Have you ever been diagnosed with ADD/ADHD?
| TeMPOraL wrote:
| Or you find yourself married and with children, and that
| final step of regaining some bandwidth becomes
| structurally impossible to achieve.
| hilbert42 wrote:
| It all adds up to what I call the 'overhead of living
| problem'.
| robk wrote:
| This is more useful than Teflon tape I find
| https://www.amazon.co.uk/Loctite-K97870-Henkel-Sealing-Multi...
| aidos wrote:
| I think there's cultural difference where the tongue in cheek
| context has been lost a bit.
|
| They probably use neither 10 full wraps, nor an enraged
| mountain gorilla, but then I've seen stranger things in
| plumbing.
| fuzzfactor wrote:
| The lowland gorilla comes to mind . . .
| azalemeth wrote:
| I particularly _hate_ the confusion that BSP and NPT cause.
| They 're almost interchangeable (differing, iirc, probably on
| the angle of flank) and will get about three turns in and then
| leak or fail under pressure. In my world, this has led to
| graduate students spraying liquid nitrogen around. It's clearly
| the case that the two probably were supposed to be identical
| but diverted due to manufacturing differences in the distant
| past.
|
| The standard advice I've been given when it comes to either
| vacuum or cryo fittings is "cut anything American off it as
| soon as it arrives and put DIN standard or KF kit on as soon as
| possible". Standards are a pain and that xkcd about there being
| too many of them is very, very true.
| iancmceachern wrote:
| Little nit pick. BSP is British.
| mgarfias wrote:
| A small quibble: the tape don't seal. It's a lubricant for the
| threads wedging together to seal.
|
| For a REALLY good primer on the subject, read Carrol Smith's
| _Nuts, Bolts, Fasteners and Plumbing Handbook_ (aka Screw to
| Win).
| pengaru wrote:
| > For a REALLY good primer on the subject, read Carrol
| Smith's _Nuts, Bolts, Fasteners and Plumbing Handbook_ (aka
| Screw to Win).
|
| +1 for anything by Carrol Smith
|
| Back in my gearhead days Engineer To Win was a near constant
| fixture next to the toilet.
| mgarfias wrote:
| I had no idea he lived nearby when I was in HS (also
| Gurney's shop was within biking distance, also didn't know
| it).
|
| If I could go back I'd blow off all the dumb shit I did and
| go ask to push a broom all day just to hang around race
| cars and learn.
| johnwalkr wrote:
| Such a great book. I'm a mechanical/aerospace engineer and
| it's astounding how many in my field don't understand
| fasteners and tend to oversize them. It's seen as
| conservative but it can actually backfire.
| kortex wrote:
| > the tape don't seal.
|
| No, the tape absolutely contributes to the seal. Sure, the
| lubrication lets you thread more tightly without binding, but
| that's not to say the tape isn't contributing to the seal. If
| it didn't, you would still have a spiral leakage path. PTFE
| tape is soft enough that it deforms and prevents the spiral
| leakage path which can occur with any tapered threaded joint.
|
| I've actually used PTFE tape in super high pressure
| situations (>1000 psi) with straight (un-tapered) joints (you
| aren't typically supposed to, but this was for an
| experiment), and it indeed sealed.
|
| > The tape also works as a deformable filler and thread
| lubricant, helping to seal the joint without hardening or
| making it more difficult to tighten
|
| https://en.wikipedia.org/wiki/Thread_seal_tape
| mannykannot wrote:
| What do you think of the advice that it is acceptable to use a
| tapered male thread in a straight female one? My guess is that
| if you do that, you have at best one turn of the thread helix
| holding them together and providing a seal (and perhaps you
| would be trusting in nothing more than the tape jammed between
| the threads if you used ten turns of it!)
| [deleted]
| johnwalkr wrote:
| I don't think it's acceptable. Maybe works in pinch to get
| through a weekend but I would always replace it with a proper
| fitting. Plus if you damage the female threads or o-ring
| seat, you've made a much worse problem for yourself.
| berjin wrote:
| If you want a really good seal you wrap the tape 1-2 overlaps
| at the start of the thread and progressively make it thicker
| and thicker so you have more overlaps (10x) at the base. I
| guess it depends on the fittings but some run out of tapper and
| you can't tighten it anymore without the hexagonal nut hitting
| the adjacent fitting. This works well as you're building your
| own tapper which is sort of acting as an o-ring.
|
| Generally BSP male fittings are always tapped which is why they
| don't mention it.
| jakewins wrote:
| Do you have a reference for this? Everything I've read is the
| purpose of the tape is to reduce friction (hence PTFE), not
| to actually seal. In other words, the seal comes from the
| fittings connecting tightly, made possible by 2-3 wraps of
| PTFE low friction tape.
| XorNot wrote:
| PTFE tape is meant to block the helical path around the
| screw threads for leaks to propagate. For parallel threads
| it's absolutely vital.
|
| Taper threads are designed to crush together to achieve
| something similar, but for what's available at the hardware
| store I've always had problems.
| [deleted]
| Kaibeezy wrote:
| All this plumbing talk got me remembering the time I redid a
| bunch of the copper in a fixer-upper. Reading up on solder
| joints, I got into the underlying metallurgy, and discovered
| solder isn't "glue". You have to abrade it to remove the oxide,
| quickly cover the raw copper with flux, and then let the boiling
| flux draw the molten solder into the joint. It doesn't take much,
| and you end up with a metal-metal-metal bond. Once I understood
| the point, the joints were a breeze. Later, I had a pro plumber
| in to deal with some iron pipe, noticed my copper work and was
| impressed. Very satisfying.
| Scoundreller wrote:
| > and discovered solder isn't "glue".
|
| I see you've never had the chance to observe some of my PCB
| work!
| rzzzt wrote:
| "The bigger the glob, the better the job". Some solder joints
| are structural.
| scotty79 wrote:
| I'm really not confident about copper pipes. Metals in solder
| are very different electrochemically than copper. There might
| be other electrically connected metals in the installation.
| There might be some impurities grains in the copper.
|
| I've seen videos of copper pipes developing pinhole leak from
| corrision.
|
| I always used aluPEX for doing the piping.
| everyone wrote:
| Programming is analogous to a trade like plumbing in many ways
| imo.
|
| * You both design and then build a thing.
|
| * No one else knows how it works or cares until it stops working.
|
| * Through work you build up your own set tools and methods that
| you like and can apply to various jobs.
| joshuaheard wrote:
| I had to learn the arcane world of pipe fitting sizes working
| with pneumatics for a scuba equipment project. It is extremely
| confusing. Unfortunately, it can have fatal consequences. In a
| recent story, a scuba store employee used the wrong size fitting
| on a 3,000 psi scuba tank which shot out and killed them.
|
| Seeing that American can't even adopt the metric system, I have
| little hope for a clear international standard for pipe fittings.
| noNothing wrote:
| All Americans completely understand the metric system. We can
| convert anything to anything in our heads. By the way, we all
| speak a dozen foreign languages fluently, just choose not to.
| It is because we are so humble that you do not know this.
| mindslight wrote:
| Cheap fittings from GENSYM sellers on Amazon/Ebay/Aliexpress will
| have crappy threads, which will cause you endless pain. I'm
| guessing this is what inspired the author's rant. I generally try
| to buy fittings from suppliers that have an incentive to do some
| quality control. If one thread in a joint isn't perfect you're
| probably fine, but when both are terribly out of spec, it will
| never seal.
|
| I see the author used the word "spanner" so I assume they're
| British which is why they have to earnestly deal with BSP. For
| fellow Americans, don't get anything BSP/BSPP/BSPT unless you
| have to (eg hydraulics commonly use BSPP/G-thread, and the bonded
| rubber washer is not optional).
|
| For pipe tape/dope, the important thing to know is their main
| purpose is to reduce friction so you can tighten a joint further,
| which deforms the threads more - packing the threads is a
| secondary effect. I generally do dope, then 2-3 wraps of tape (in
| the right direction, of course), then dope again. I generally use
| the thicker blue tape, but thinner white should be the same with
| a few more wraps. I learned this trick from an old timer at a
| hardware store, and it has definitely helped on some recalcitrant
| joints. I'd rather not find leaks after something is assembled,
| so I just take the time and do it on most every joint now. (For
| reference, I mostly deal with 1/4 - 1 inch NPT
| brass/stainless/copper threads).
|
| Also, not every type of connection takes dope/tape! For example,
| while US showers generally have NPT-M coming out of the wall, the
| showerhead generally has a rubber washer that makes the seal, and
| thus does not need tape. Similarly with flare/compression
| fittings.
|
| Also, plumbers get paid a lot because it's generally heavily
| regulated - water supply contamination is one of those things
| we've refined over centuries and now take for granted. The
| regulation means they get a middle class wage, which is
| prohibitively expensive for other individuals to pay owing to
| high taxes and other overhead. Imagine how much it would cost to
| hire yourself as a software engineer for half a day.
| jsz0 wrote:
| I had to do some plumbing work a few years ago and quite enjoyed
| solving the puzzle and completing the work myself. It did remind
| me a lot of my day job in tech. No individual part of the job is
| all that difficult but planning and executing everything
| properly, and all the cryptic/arcane knowledge required, was very
| similar. And just like when one of my networks or systems is down
| the work had to be completed quickly to resolve the outage.
| blincoln wrote:
| I've helped out with some plumbing work in an older house, and
| it's pretty fascinating to see the progression of technologies.
|
| 100 years ago, most drain pipes in the US were massive cast-iron
| pieces with no threads at all. They were mated together, then the
| joint was filled with a compound called oakum. To really hold it
| together, the plumber would pour molten lead on top of the oakum.
| Just taking that stuff apart is a lot of work. I can't imagine
| putting it together as well, especially for 40 hours a week.
|
| I agree with the author's dismay about threaded fittings, but
| 100% disagree about PTFE tape versus thread sealant. PTFE tape is
| garbage. If you use thread sealer the way it's supposed to be
| used (put on a decent amount, then thread the pieces together
| with the "nudge and a grunt" technique instead of cranking down
| on it with a huge amount of force), it will seal perfectly almost
| every time, and any minor leaks can usually be fixed by
| tightening the joint slightly. If that's not enough, just take it
| apart and redo it. I've rarely had to try twice, and never three
| times.
|
| Not sure about British threaded pipe, but NPT threaded pipe
| actually doesn't benefit from being tightened beyond a certain
| point because of the way the threads are designed. I redid the
| seals and some of the fittings[1] on all the antique hot water
| radiators in a house because no contractor within a day's travel
| would work on antique hydronic heating systems. Good quality
| thread sealant, no garbagey PTFE tape, no leaks, even in constant
| use.
|
| That having been said, modern pipes and fittings make things dead
| simple. PVC (or ABS, but PVC is nicer IMO) for drains, push-to-
| connect fittings for water lines (I like PEX, but I know opinions
| vary). No lead, no torches. Easy to cut with hand tools.
| Lightweight. Anyone who's interested can probably do at least
| basic work with modern pipes.
|
| [1] https://youtube.com/watch?v=MeHiE-j1KuQ
| Tijdreiziger wrote:
| > To really hold it together, the plumber would pour molten
| lead on top of the oakum.
|
| This is pretty interesting, because plumbers are called 'lead-
| pourers' (loodgieters) in Dutch, and I had always wondered why.
| skeptical_dog wrote:
| The english word, too, is derived from the Latin for lead:
| plumbum.
| jimnotgym wrote:
| In fact _some_ plumbers still do lead work. Lead sheet roof
| flashings are common in the UK. Roofers can beat it into
| certain shapes, but if you need something more complex you
| would get a plumber to weld it for you.
|
| I learnt to lead-weld (with oxy acetylene) in the past and
| found it very satisfying...
| Scoundreller wrote:
| It's not called Pb for nothing!
| beerandt wrote:
| Except the meaning is to plumb, as in to level, as in to
| get water flowing downhill.
|
| The lead refers to the (lead) plumb bob used to determine
| the direction of vertical and therefore what's level.
| robocat wrote:
| https://etymology.en-academic.com/27822/plumber
|
| https://etymology.en-academic.com/27820/plumb
|
| It appears you are wrong, and the person you are replying
| to was correct. Perhaps when baldly contradicting
| someone, you could make some effort to back up your
| opinion.
| beerandt wrote:
| The first 2 meanings of plumb from the site you link is:
|
| https://etymology.en-academic.com/27820/plumb
|
| plumb plumb {{11}}plumb (adj.) "perpendicular, vertical,"
| mid-15c., from PLUMB (Cf. plumb) (n.). The notion of
| "exact measurement" led to extended sense of "completely,
| downright" (1748), sometimes spelled plump or plunk.
|
| {{12}}plumb (n.) c.1300, "lead hung on a string to show
| the vertical line," from O.Fr. _plombe, plomme "sounding
| lead," from L.L. _plumba, originally plural of L. plumbum
| "lead," the metal, of unknown origin, related to Gk.
| molybdos "lead"
|
| Neither have anything to do with pouring molten lead.
| Only measuring the vertical.
|
| The purpose of finding the vertical is to determine the
| horizontal in installing sloped pipe.
| robocat wrote:
| I skimmed what appear to be reliable references, and they
| all mention the Latin -> French -> English etymology for
| plumber, and they do not reference "plumb" in the sense
| you are using.
|
| I suspect that plunging in and making a poor argument
| doesn't reflect well upon you. I am happy to be
| corrected, if you can provide a rock-solid reference: the
| English language is a wonderful midden.
| eesmith wrote:
| Whilst "plumb" comes the Latin for "lead", so does
| "plumber", and from a different and earlier path than
| "plumb". Quoting https://www.etymonline.com/word/plumber#
| etymonline_v_17491 :
|
| > late 14c. (from c. 1100 as a surname), "a worker in any
| sort of lead" (roofs, gutters, pipes), from Old French
| plomier "lead-smelter" (Modern French plombier) and
| directly from Latin plumbarius "worker in lead," noun use
| of adjective meaning "pertaining to lead," from plumbum
| "lead" (see plumb (n.)). The meaning focused 19c. on
| "workman who installs pipes and fittings" as lead pipes
| for conveying water and gas became the principal concern
| of the trade.
|
| We can read Vitruvius' description of chorobates at https
| ://penelope.uchicago.edu/Thayer/E/Roman/Texts/Vitruvius..
| . (Note that https://ethw.org/Roman_Aqueducts claims "the
| credit given to this instrument by Vitruvius was out of
| proportion to its real usefulness.")
|
| > The chorobates is a rod about *twenty feet in length,
| having two legs at its extremities of equal length and
| dimensions, and fastened to the ends of the rod at right
| angles with it; between the rod and the legs are cross
| pieces fastened with tenons, whereon vertical lines are
| correctly marked, through which correspondent plumb lines
| hang down from the rod. When the rod is set, these will
| coincide with the lines marked, and shew that the
| instrument stands level.
|
| The Latin for "plumb lines" is seen in "quae habent
| lineas ad perpendiculum recte descriptas pendentiaque ex
| regula perpendicula in singulis partibus" - Vitruvius
| does not use a variation of "plumb" to describe those
| verticals.
|
| That usage, from the quoted etymology, wasn't created for
| another 1,000+ years.
|
| I could be wrong of course, but the evidence I've seen
| doesn't support your claim at
| https://news.ycombinator.com/item?id=33765351 .
| manojlds wrote:
| And plumbers are called plumbers in English because they work
| in plumbings?
|
| Same origin in English as well! (Plumbum = Lead)
| [deleted]
| blincoln wrote:
| Just to be clear, I'm not trying to discount the skill and
| knowledge of professional plumbers. It's an incredibly complex
| field (especially since they need to be familiar with decades
| of different pipe technology), and usually involves working in
| filthy parts of the house no one else wants to go into. They
| deserve every penny.
| MomoXenosaga wrote:
| Normally the market is supposed to correct these things but
| sadly we've created a culture that looks down on physical
| labour. Now there is a small group that can charge whatever
| they want.
| toast0 wrote:
| They can't charge that much or people will do their own
| plumbing. It's fussy, but most routine things aren't too
| hard to do one step at a time. Sometimes you get a new
| faucet with an internal leak though, experience might have
| helped diagnose that without taking everything apart 20
| times. Sometimes there's a big job like replacing a
| lateral, which is yeah, time to hire a pro.
| jimnotgym wrote:
| In the UK gas work is regulated so only a registered
| plumber can do it.
| sacrosancty wrote:
| bathtub365 wrote:
| Is the market not supposed to reflect culture?
| ElevenLathe wrote:
| This is an outdated ideology. Now the market is meant to
| define correctness. Deviation from the perfect wisdom of
| the market is the only form of sin.
| cmclaughlin wrote:
| > I like PEX, but I know opinions vary
|
| What's not to like about PEX?
| johnmaguire wrote:
| I believe it's less durable than alternatives.
| Scoundreller wrote:
| There's definitely a "right" way and a "wrong" way to do
| it.
|
| Having each fixture connection being a "home run" without
| _any_ fittings between source and destination really
| reduces a lot of vulnerabilities. Having a central manifold
| that lets you easily turn off any tap is nice too.
|
| A condo building I lived in did something wrong (I suspect)
| either a bad batch of PEX, or more likely, a batch that sat
| in the sun for a while, leading to multiple failures of hot
| water return lines in few years that were a mystery to pin
| down.
| iancmceachern wrote:
| Also using the compression fittings with a good crimping
| tool, not the push to connect fittings IMO is more
| durable and reliable.
| frosted-flakes wrote:
| Home run plumbing also means a _lot_ of pipes in the
| walls, so you end up with 20x more pipes in the walls and
| ceiling than is actually necessary, and 20+ valves, which
| are often made of plastic instead of brass because
| otherwise costs would balloon. In any case, the fittings
| aren 't the weak point, the pipe is; a properly crimped
| joint or expansion joint will never leak. And often it's
| impossible to have no fittings on a run of pipe anyway.
|
| In my opinion, traditional trunk and branch plumbing is
| far more flexible and just as reliable. It also allows
| for a hot water recirculation loop, which is impossible
| with home-run plumbing.
| bluGill wrote:
| Actually pex is probably the most durable. Water is
| corrosive and will slowly dissolve metal pipes .
|
| Pex has zero UV resistance though, sp if exposed to sun at
| all it is the least durable.
| mindslight wrote:
| Thinking about a system a half-step up from hose clamps
| holding 100psi of pressure, which if it pulls apart will
| rapidly release hundreds of gallons of water does not inspire
| confidence. And since the house is already plumbed with
| copper and I know how to sweat joints, I might as well
| continue that.
|
| I'm about to use PEX for the first time on my hydronic
| heating system, which is only ~20psi and limited volume
| (autofill valves are an anti-pattern). Maybe I'll fall in
| love, who knows.
| D13Fd wrote:
| I haven't seen 100 psi in household applications
| mindslight wrote:
| My city water pressure was around there, with few ill
| effects. I've since installed a pressure regular to drop
| it to around 60psi. But I liked it better before,
| especially on the silcocks.
|
| It's not really the pressure that has me worried, but
| rather the potential flow rate. I've dealt with a flooded
| basement before, and I'd rather not do it again.
|
| I don't see many people complaining that PEX fails by
| completely pulling apart, but it's hard for my intuition
| to accept that.
| sokoloff wrote:
| Be sure to read up on oxygen barrier vs permeable Pex. (You
| probably already have, but if not, you almost certainly
| want barrier Pex in a closed-loop system.)
| blincoln wrote:
| One of the things I like about it is that because it's
| flexible, if you route it carefully you can avoid using
| connectors in a lot of areas that rigid pipe would require
| a joint. The way I saw it used, the only joints were in
| areas like cleanout access and crawlspaces, so even if a
| joint went bad, it wouldn't require opening up a wall to
| fix. I'm not a pro, so maybe rigid pipe is supposed to only
| have joints in accessible areas too, but that certainly
| wasn't the case with the century-old plumbing I saw.
|
| It's still relatively new compared to other pipe material,
| so there may be some other surprises that crop up with long
| term use, but I'm really impressed with its ease of
| installation.
| jimnotgym wrote:
| One thing about plastic pipe is that it is susceptible to
| rodent damage, unlike copper.
|
| Seen it a few times.
| TEP_Kim_Il_Sung wrote:
| hemp fiber > PTFE tape
| blincoln wrote:
| For sure. Those oakum + lead joints were problem-free a
| century after they were installed. How many of us can expect
| that from the things we do at work?
|
| The only reason some of that pipe needed to be replaced was
| that it was fused (by rust) to mid-20th-century galvanized
| pipe that had rusted completely shut.
| dotancohen wrote:
| Those lead joints were leaching lead into the water. If it
| was a supply pipe, as opposed to a drain, then people were
| ingesting that lead. It needed to be replaced whether it
| was leaking or not.
| blincoln wrote:
| It was just the drain pipe system that was built that way
| (at least in the house I helped out with). All of the
| supply lines were galvanized steel, replaced with PEX.
| jaggederest wrote:
| The lead in those joints never touches liquid. It's a
| sealant on the back of the oakum, which is what does the
| actual water contacting.
|
| Also, nearly all water supplies (municipal, at least) are
| pH adjusted to be slightly basic, which causes lead to
| form lead carbonates and oxides, which is (basically)
| insoluble in cold water. Still good policy to replace
| lead supply lines, but not a crisis unless you allow your
| water quality to fluctuate (ala Flint or a number of
| other US cities, sadly)
| Scoundreller wrote:
| More recently, beyond pH control, cities are doing
| orthophosphte corrosion control. Nearly universal in UK
| but hit and miss in other places.
|
| https://www.haldimandcounty.ca/wp-
| content/uploads/2018/07/Or...
|
| A big source of lead can be recently sweated copper lines
| (takes a while for the corrosion control to coat it), but
| lead solder isn't _supposed_ to be in potable use
| anymore. And old fixtures!
|
| Even newer "lead-free" fixtures aren't 0% lead.
|
| https://www.epa.gov/sdwa/questions-and-answers-about-
| final-l...
| jaggederest wrote:
| Yes I've found it's very frustrating looking for
| "genuinely zero lead" brass and bronze. Almost all scrap
| has lead in it to some degree, and even new metal often
| has a trace.
| TEP_Kim_Il_Sung wrote:
| Remove about 82% of lead from bronze using this one weird
| trick!
|
| https://www.researchgate.net/publication/250155103_Remova
| l_o...
| Scoundreller wrote:
| I was hoping for something involving a particle
| accelerator and making gold.
| NegativeLatency wrote:
| Generally the lead joints described above were only used
| for waste plumbing where the max pressure is very very much
| lower than the water supply pressure
| baybal2 wrote:
| blincoln wrote:
| Also, I should mention that I've used PTFE tape without any
| issues for air tool connections. It's just for plumbing - where
| even a slow, tiny leak can cause massive damage - where I think
| it's a terrible choice.
| scotty79 wrote:
| It's perfectly usable but you need to wrap a lot of it. If
| you wrap so long that you can barely make out a thread
| underneeth you can have a good seal lasting decades even if
| you don't screw the thread in completely.
|
| On steel pipes and fittings obviously. Plastic ones might
| crack.
|
| Also hemp fiber requires bit more practice and leverage but
| it's really good.
| naich wrote:
| Having just completed a small project involving plumbing, this
| post on my blog comes from the heart.
| typhonic wrote:
| There are plenty of technical comments here, but I have to say
| I got a great laugh from this post. I have dealt with many of
| the absurdities state side, so I can relate to your experience.
| By the time I got to the words Windows XP Screensaver, I was
| laughing so hard I couldn't read anymore. After finishing, I
| bookmarked you. Looking forward to more. Thanks.
| AlbertCory wrote:
| I had a doctor once who was quitting his solo practice and taking
| a regular job at a hospital, having become disillusioned with the
| biz. He said his house was bought by a plumber, who was trading
| up.
| xyzelement wrote:
| Why "someone" gets paid a lot was a discussion topics this
| Thanksgiving. The answer is as always "law of supply and demand."
|
| Want to make money? Learn to do something people really need but
| not a lot of them can or want to do.
|
| Perhaps pipe fitting is one of the "things" for plummers.
| lisper wrote:
| Best. Conclusion. Ever.
| tehwebguy wrote:
| Probably because you only call them when building or solving a
| water or poop related emergency, so times when you _really_ need
| a plumber.
|
| Interesting read about the pipe fittings too though!
| 1970-01-01 wrote:
| They're paid so much because you need to pay twice for the bad
| ones. My house's previous plumber threaded a copper line directly
| into the stainless steel DHW tank. That wasn't a problem, until
| it was.
| amluto wrote:
| I've never encountered a DHW tank made of stainless steel with
| stainless steel fittings.
|
| The error that _will_ destroy your pipes is to use anything
| copper in the condensate plumbing of a condensing boiler. Use
| PVC, CPVC or PEX (or stainless steel) with _plastic_ fittings
| (PVC, CPVC, "engineered polymer", or John Guest ProLock or
| similar). The high CO2 concentrations in the condensate will
| rapidly corrode copper.
| zbrozek wrote:
| https://www.chiltrix.com/heat-exchanger-tanks/DHW80.pdf
| bmalicoat wrote:
| I was hoping this was going to be written by Leslie Claret.
|
| https://www.lgclaret.com/
|
| "Hey, let me walk you through our Donnelly nut spacing and crack
| system rim-riding grip configuration. Using a field of half-C
| sprats, and brass-fitted nickel slits, our bracketed caps and
| splay-flexed brace columns vent dampers to dampening hatch depths
| of one-half meter from the damper crown to the spurve plinths.
| How? Well, we bolster twelve husked nuts to each girdle-jerry.
| While flex tandems press a task apparatus of ten vertically
| composited patch-hamplers. Then, pin flam-fastened pan traps at
| both maiden-apexes of the jim-joist."
| dtjohnnymonkey wrote:
| This is what I came here looking for.
| ok_computer wrote:
| Bsp, Npt, goop (yuck!), and teflon tape are all inferior to
| Swage. Cold weld and reuseable but it is a trade in itself to fit
| and bend to place.
|
| https://en.m.wikipedia.org/wiki/Compression_fitting
|
| Working in labs on fluid and vacuum lines (<1in diameter) this is
| the way.
|
| If only it wouldn't cost as much as the house in fittings + tube
| to hardpipe stainless fittings on our water supply lines.
|
| I stayed in a hostel hotel in Munich, DE with hard piped bathroom
| water lines. I was impressed and think they must have been in
| service for 30-50 years.
| walrus01 wrote:
| Of other industrial interest re: pipes, sch40 and sch80 hot dip
| galvanized pipes in various outer diameters are also a standard
| item for telecom construction projects.
|
| For when you want to have a pipe-to-pipe adapter to hang a radio
| on a tower, or wall mount it on top of a building mechanical
| penthouse or similar.
| zabzonk wrote:
| i got worried at this point:
|
| "imagine putting a tapered male in a straight female"
| csours wrote:
| Because they are licensed, and the license requires the
| equivalent of apprenticeship.
| zackbloom wrote:
| I would personally recommend trying TFE paste, rather than Teflon
| tape. Easier to get a seal, less annoying to tighten.
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