[HN Gopher] Repairing my mug with Kintsugi
___________________________________________________________________
Repairing my mug with Kintsugi
Author : fellerts
Score : 588 points
Date : 2024-05-31 09:57 UTC (2 days ago)
(HTM) web link (fellerts.no)
(TXT) w3m dump (fellerts.no)
| throwup238 wrote:
| _> These days, some hobbyists opt for modern epoxy instead of the
| traditional and expensive Urushi lacquer. Epoxy probably yields a
| more robust bond and certainly allows for quicker repairs, but I
| question its safety for food-related use, especially at the
| temperatures found in a steaming cup of coffee._
|
| People opt for epoxy because Urushi lacquer is traditionally made
| from poison oak sap and is a potent skin irritant to most people
| (it's where urushiol gets its name). It's really tough to do
| Kintsugi without smearing trace amounts of it all over the place,
| especially if you're doing it with kids, and cleaning it off is a
| pain since it's a hydrophobic sap. Even trace amounts can cause a
| reaction, especially if someone has sensitive skin or is severely
| allergic. People who do a lot of kintsugi develop a tolerance for
| it but it's an annoyance that most hobbyists just don't need.
|
| Epoxies can be perfectly food safe and the FDA has a database [1]
| although it's not particularly user friendly. You can get MAX CLR
| or similar from Amazon. I wouldn't use it in an oven above 300F
| but it's fine for boiling temps. These FDA approved two part
| epoxies are used all over the place in hospitals and food
| manufacturing facilities where they're used to coat rough
| surfaces that would otherwise harbor bacteria.
|
| [1]
| https://www.cfsanappsexternal.fda.gov/scripts/fdcc/?set=Indi...
| giraffe_lady wrote:
| I spent a few years messing with different approaches with
| epoxy but I never found anything that could replace urushi.
| It's really hard to get foodsafe epoxy to cure as hard as
| urushi, though I did eventually get one I was happy with. But
| the wheat flour in the traditional material pulls the shards
| together as it dries, and gives just an incredibly tight and
| strong bond that can really hold up to actual use of the
| restored vessel. Epoxy always weakens and fails after a while,
| while I have urushi/wheat/clay pieces that have been in daily
| use for years.
|
| Depending on your goals though non-foodsafe epoxy can work
| well. Thickened marine epoxy, for under-the-waterline boat
| repairs is rock solid for decorative items. I'm sure it's toxic
| af and I wouldn't want it anywhere near my food but it would be
| fine for a lot of the things people want to do kintsugi for.
|
| Cashew lacquer is also pretty cool. It's nowhere near as nasty
| as urushi and doesn't require a special environment for curing.
| If I were just getting into it now I'd probably start with
| that.
| elihu wrote:
| Weirdly enough, the food safety of urushiol was the topic of
| this recent and heavily discussed HN post:
| https://news.ycombinator.com/item?id=40399224
|
| I can't say I have any desire to try it myself.
| fellerts wrote:
| I'm not a doctor/chemist, but as far as I understand, the
| polymerization of urushiol renders it hard and inert. Your
| thread discusses contact with raw urushiol as found in poison
| ivy, cashew sap (and apparently mangos) which is indeed known
| to cause allergic rashes in most humans. I'm not saying that
| kintsugi is definitely food-safe, but it's an important
| distinction.
|
| Side-note: I did get some raw urushi on my fingers while
| working on this project, but nothing happened. Perhaps I'm
| immune.
| throwup238 wrote:
| _> Side-note: I did get some raw urushi on my fingers while
| working on this project, but nothing happened. Perhaps I 'm
| immune._
|
| Might also be enough mechanical rubbing on fingertips
| during normal use that it mostly scrubs off. Whenever I
| feel it coming on from Urushi or accidentally touching
| poison ivy in nature, I rub it with water and course
| sand/dirt which seems to get rid of the urushiol.
| qwerpy wrote:
| How do you "feel it coming on"? Would love to develop a
| sense for it so I can save myself from days of
| discomfort.
| throwup238 wrote:
| I have sensitive skin so I start to itch shortly after
| contact and it builds from there. If I get it scrubbed
| off fast enough after exposure, I can usually prevent
| full contact dermatitis from setting in.
|
| Urushi is more of a pain in the ass because its made from
| the sap, but Windsor and Newton artguard barrier cream
| seems to really help. Ideally apply it before use but it
| helps washing it off too if you forget.
| abakker wrote:
| A lot of people seem immune the first time. My mom thought
| she was immune to poison ivy, but after years of contact
| she became increasingly sensitized. Now she gets a rash of
| the cat has been walking through it.
| Schattenbaer wrote:
| You can even get (tobacco) smoking pipes decorated using
| urushi. It's made me wonder about the temperature stability, as
| a pipe can (but ideally shouldn't) get fairly hot.
|
| Tsuge is a good brand to search for if you want to see
| exanples. Cost-wise such pipes start around the two hundred US
| mark.
| harimau777 wrote:
| I've never trusted that food safe epoxy actually is. I'm afraid
| that lobbyists have interfered, or its a situation where
| "there's no evidence that it's dangerous but there's not really
| evidence that it's safe", or the studies are funded by
| manufacturers, or there's something like manufactures pulled
| with BPA where they just switch to something functionally
| equivalent to a potentially dangerous chemical.
|
| Is there any reason to believe that these epoxies won't just be
| like PFAS where in a few years the EPA/FDA will decide that
| they were actually risky?
| doctorhandshake wrote:
| I'm with you. I assume all plastics to be unsafe for human
| use by default.
| bee_rider wrote:
| I'm always worried about food-safety and Amazon. They don't
| have very good control over their inventory, right?
| thot_experiment wrote:
| I recently broke a piece of glassware that had been with me for
| over a decade. I have all the pieces and I'm wondering if it's
| possible to stick it in a kiln and run a heat cycle that will
| cause all the cracks to flow together without deforming the
| shape, and barring that if there's a thin gold glue I could use
| to do some approximation of this technique but with cracks that
| are essentially zero width.
| throwup238 wrote:
| A _very_ skilled glassmaker might be able to fuse the pieces
| together by heating the edges and pushing them together if the
| piece is simple enough but in general, no. That 's why it's
| called glass _blowing_ : the air pressure is what gives the
| glass form while it cools and vitrifies.
| chris1993 wrote:
| The BBC "repair shop" show recently (last year?) had an episode
| repairing a shattered vase with some specialist glass repair
| glue, so you can probably find some for this.
| hcrean wrote:
| There is a method where you piece the glass together supported
| in investment, (a type of ceramic casting plaster), by building
| it up in layers. You tightly pack it and put it in the kiln,
| the investment holds the shape of the object when it melts.
|
| This is a very advanced and difficult method of glass re-
| forming.
| Baeocystin wrote:
| The short answer is no. You will not get fusion without slump.
|
| That being said, there are excellent, optically-clear, UV
| stable epoxies that are made for this problem. Hxtal is the go-
| to for most.
| https://www.lakesidepottery.com/HTML%20Text/Tips/Hxtal-NYL-i...
|
| It is very thin, and will happily wick in and fill cracks.
| Often the join is completely invisible. The downside is that
| the cure time is on the order of 1-2 weeks. It does take a
| little practice to use effectively, and it's worth trying on
| less-important projects first, but it's straightforward enough
| that you can expect success if you follow the directions
| carefully.
| talkingtab wrote:
| I would seriously consider kintsugi for aesthetic reasons. You
| do not have to go with the gold thing. Basic urushi is black so
| you could go with just black. You can also get Urushi in quite
| a wonderful red. And there is truly spectacular orange.
|
| As for the aesthetics. No matter what you do, you don't get a
| whole piece. It is broken and always will be. What you can do
| is to create something new that both has the beauty of the old
| and the care, beauty, whatever of continuing. I don't know how
| to explain this in logic, but there it is. I had quite a nice
| ceramic cup with charm that broke. I used black urushi which
| was not gaudy like gold leaf can be. I liked it even more than
| before.
|
| Another option is silver leaf instead of gold depending on the
| glassware. And finally you can get really crazy. Rankaku is
| where you get little tiny pieces of quail egg shell and place
| it into the urushi. It is painstaking - to say the least- but
| the results can be beyond stunning.
| https://www.pinterest.com/pin/jean-dunand-18771942--55309901...
| thingsilearned wrote:
| For those of you in the Bay Area there's a great Kintsugi
| workshop that's run out of the SF zen center almost weekly
| https://stonegoldcrafts.com/
|
| I got into Kintsugi when my toilet needed repair. It's a
| rewarding craft https://thingsilearned.com/things/my-kintsugi-
| toilet/
| avtar wrote:
| For those in Toronto :) https://introjapan.ca/inperson-classes/
|
| No affiliation. I gifted my partner an intro workshop pass and
| she's been returning for more classes since then.
| criddell wrote:
| How do you discover classes like this? Are there city-
| specific guides to interesting classes and seminars that you
| can take?
| mholt wrote:
| I'm also looking. The University of Utah has a random one-
| off kintsugi course this fall but I think it's full
| already.
| avtar wrote:
| I wish I could offer something more useful, but in this
| case her birthday was fast approaching and I remembered her
| bringing up Kintsugi in a conversation. I did a search for
| "kintsugi toronto" and found that teacher's site on the
| first results page. Back in the day I would have browsed
| craigslist, but unfortunately it's not as popular here
| anymore.
| kelnos wrote:
| I've attended one of those at the Zen Center! My partner took
| me to one as a birthday present last year. She ended up being
| kinda frustrated with the process, but I found it soothing and
| relaxing, and left happy and contented.
|
| The guy running the workshop had us use epoxy and not urushi
| powder (not surprising; I'm sure all of us would have ended up
| with severe skin irritation otherwise). The article mentions
| concerns about food safety; IIRC we were told that the epoxy we
| were using in the workshop was not food safe, but that it's
| easy to acquire food-safe versions of it.
|
| We also didn't do this in anywhere near as many steps, with as
| many different treatments for different sizes/shapes of damage.
| Ultimately we fully repaired a piece in a couple hours, not the
| several months that the article author took to do it right.
| (And the extra care and use of the proper materials shows; the
| final repaired alligator mug from the article looks orders of
| magnitude better than my work.)
| JSR_FDED wrote:
| This is super inspiring and the end result is amazing,
| congratulations!
| kelnos wrote:
| > _I knocked it off the kitchen counter and, giving into the
| idiotic reflex of trying to catch it with my foot, kicked it into
| the wall instead_
|
| Not idiotic! I've saved more things than I've further damaged by
| doing this.
| sunaookami wrote:
| Unless you are dropping a knife ;)
| mauvehaus wrote:
| Or the business end of a blender. Or a big-ass chisel.
|
| Not hypotheticals, either of those, and not me.
| smeej wrote:
| I have a chisel scar on my hand that I call my "get down
| and move the damn ladder" reminder scar.
| jen729w wrote:
| I've done this with a new and thus terribly sharp knife. I'd
| bought it for my mate, so when I knocked it off the bench my
| reaction was _oh no! damage! catch!_
|
| The kitchen looked like a scene from Kill Bill. Perfect blood
| spray in an arc across the wall.
|
| This mate lived with me at the time. And he was a nurse. He
| came home from his shift about half an hour later and I told
| him, sorry man, but you're driving me straight back to the
| hospital.
|
| I'm lucky to still have total use of my right middle finger.
| namibj wrote:
| That's why you keep a second mode trained that instead makes
| you jump away from the uncontrolled blade.
| smrq wrote:
| Once, many years ago, I dropped a knife and caught it,
| fortunately by the handle. I felt very stupid for the obvious
| reason, but my cat was by my feet at the time--so I'm not
| even sure it was the wrong thing to do. Well, crisis averted,
| one way or another...
| giraffe_lady wrote:
| This is really great results for an early project, none of my
| first few came out anywhere near so good.
|
| I've been doing traditional kintsugi for about twelve years, a
| couple hundred successful repairs. Though when I started there
| was very little instruction or english-language resources
| available. It's become pretty popular for obvious reasons which
| is great for people getting into it now.
|
| It remains probably the most difficult and frustrating skill I've
| ever learned. It's really hard to communicate just how
| meticulous, near-impossible some of the joins can be. There is a
| _huge_ variety of technique and nuance to learn about different
| media and lacquer ratios for different kinds of joins & fills
| and it all needs to be done by intuition and experience.
|
| And then the medium has no holding power until the curing process
| is well underway. So you need a lot of creativity to come up with
| a scaffolding system, pretty much completely unique to each
| project. Any problem after applying lacquer means hours of
| careful filing and rework, and more days or weeks of curing.
|
| An edge-of-my-skill repair on a complete shatter takes about 100
| hours spread out over 2-3 months. Even just an ideal three piece
| clean break is easily 8-10 hours and a handful of weeks.
| fellerts wrote:
| Thank you for the kind words! I've not even scratched the
| surface of kintsugi of course, but the little I've learned
| agrees very much with what you say. It's a true test of
| patience.
|
| Are you entirely self-taught then, or did you find a mentor?
| giraffe_lady wrote:
| Almost entirely self taught. I've got a few other
| practitioners I've asked for advice over the years but no one
| who really had guidance over my learning the way a mentor
| would.
|
| Early on I got most of my info from the newberry library. It
| had a collection of illustrations and manuals donated from a
| defunct lacquerworks museum in japan, for some reason. They
| had someone around who even helped with a lot of translation
| for free which was a major help. All this stuff is available
| and better explained on youtube now though.
| cafebee wrote:
| I'm working on a shattered teapot and am finding the
| scaffolding part very difficult. Any tips on holding pieces in
| place that you'd be willing to share?
| giraffe_lady wrote:
| Sure thing. For shatters the main thing is just accept that
| it'll take a while and plan on doing it one or two pieces at
| a time, ideally starting with the biggest and working down in
| size. I've seen videos where someone is fitting a whole
| shatter together in one go and holding it with rubber bands
| but this almost never works right in my experience.
|
| A pair of good articulating arm clamps is my starting point
| for almost everything. I like to put the "main" piece
| directly under the shard that is being joined. You want the
| pieces as tight as you can get of course but you don't need a
| ton of pressure on there. The flour in the medium will draw
| it together some as it dries. If you get a good bond but it
| cures with gaps or holes in the join, you can fill in later
| with lacquer mixed with a fine clay. Tonoko or jinoko are the
| key words if you don't have it on hand.
|
| Usually there's at least one join where you need to set
| multiple pieces at the same time. _Sometimes_ I 'll use a
| single string tied across the outermost shard to keep
| pressure on, usually across the rim of a bowl or cup. More
| than one string is too much to keep track of for me though.
| And the lacquer fumes are extremely detrimental to rubber and
| elastic, they will harden and break with a few hours of
| exposure so I don't use them at all.
|
| A more traditional move is to bury the main body of the
| repair in a dish of sand, with the part to be joined exposed.
| Then arm clamps or whatever to hold the pieces together. Just
| make sure any joins that touch sand are fully cured. The
| cleaner you work the less sanding you'll have later. But
| there will always be some so do what's necessary to get it
| together then clean afterwards. I've even used masking tape
| to hold some many-pieced shatters together. It's a mess but
| it works, provided the piece doesn't have any texture or
| decorative elements that could be damaged by the sanding.
|
| Good luck! It's the most tricky and frustrating part, and
| where most of the failures happen. You should probably expect
| some failures and setbacks, it's just part of it.
| talkingtab wrote:
| Danger!!! Urushi is basically poison oak/poison ivy sap. Not
| quite the same, but in that family and with the same effects. Not
| to scare you off, but if you are interested in this, imagine all
| the things that can go wrong from if you were to get a tube of
| poison ivy sap and then do things with it.
|
| That said, Urushi is great and the number of things you can do
| with it is truly amazing. Just don't do it rashly.
| smoyer wrote:
| > rashly Good one!
| userbinator wrote:
| Most other adhesives and epoxies are also quite toxic when not
| cured.
| LoganDark wrote:
| Even if you're not allergic the first time you use them, you
| can _become_ allergic.
| bbarnett wrote:
| Sir...sir! This is hacker news! It's not some place to say
| somthong punny! What are you, The Punisher?
| mholt wrote:
| My wife recently got into kintsugi. She's learning the
| traditional method described here. I'm reading these comments
| with great interest and will be passing this onto her!
|
| Most of the methods taught in the US are "gold relief" methods,
| which is basically glue with golden pigment mixed in. It doesn't
| look great but is modern and quick. "Gold flush" methods take a
| bit more time and are more authentic, but still don't use the
| traditional materials shown in this article.
|
| Does anyone know where to get these traditional materials for use
| in classroom settings (i.e. in bulk, preferably discounted)? Not
| massive scale, just enough for a few classes. The kits have such
| a tiny amount and are so expensive, even a bulk discount of
| ~10-20% would be ideal.
| serf wrote:
| aside from 'the craft' and tradition of the process, is there any
| real benefit to using legitimate urushiol?
|
| there are _lots_ of bonding agents and epoxies out there that are
| _not_ urushi based , _actually_ food safe, and just as easily
| doused in gold dust, and completely compatible with prepared
| ceramics.
| mholt wrote:
| What's food-unsafe about cured urushi?
| conkeisterdoor wrote:
| I don't think the GP was implying that urushi isn't food
| safe, but rather that some epoxies aren't food safe
| MBCook wrote:
| The author of the peace also mentioned that while there are
| food safe epoxies they were worried that they may be less
| food safe than expected when used with high temperatures
| like tea or coffee as opposed to being used in a simple
| serving dish.
| xipho wrote:
| According to
| https://www.lakesidepottery.com/Pages/Pottery-
| tips/ceramic-r... there are no food safe epoxies,
| including Kintsugi...
| ryandamm wrote:
| Certified food grade epoxies are used in industry all the
| time; in fact, some wine is aged in epoxy-coated concrete
| tanks, and the inside of soda cans these days includes a
| thin layer of food-grade epoxy.
|
| I will not fault anyone for not believing the
| certification, but I would personally want to see a more
| authoritative source than an undated ceramics FAQ. But
| this is just personal style! Being suspicious of
| regulatory thresholds is prudent.
|
| (And this FAQ has me wanting to revisit my priors and
| research this a little more specifically, because its
| assertions are plausible, but need sources or
| explanations or dates, for cross-checking. Food-grade
| epoxy I believe in would be a handy thing to have exist;
| I do have some certified food grade epoxy in my garage
| that I haven't used for anything yet and I'd dislike
| downgrading it to just "epoxy.")
| xipho wrote:
| Completely agree. Was looking for citations too and this
| was the first I hit, wish they pointed forward.
| r2_pilot wrote:
| No worries, with Claude's assistance I came across the
| FDA's Title 21 chapter 1 subchapter B, specifically
| 21CFR175.300. You're welcome to see what the US
| government has to say versus some random ceramic
| site.(edit:tl;dr safety-tested food safe epoxies exist)
| rtpg wrote:
| so are all the fixed up tea cups actually seeping stuff
| into the drink? I get that's always possible but a teacup
| is literally a container for near-boiling water
| yegle wrote:
| Apparently there's another styles of repairing ceramic/porcelain:
| https://zh.wikipedia.org/zh-hans/%E9%94%94%E7%93%B7
| modernpink wrote:
| Apparently, it was this Chinese method of repair that horrified
| the Japanese aesthetic sensibility [0] into creating kintsugi.
|
| [0] https://en.wikipedia.org/wiki/Kintsugi#Origin
| vsgherzi wrote:
| wow it's beautiful. Amazing job. Can you still use it in a
| dishwasher or microwave?
| giraffe_lady wrote:
| I have a bunch of kintsugi stuff in regular use so I can
| answer. Microwave is a definite no! It arcs, kind of like gold-
| rimmed plates would I guess.
|
| Dishwasher you _can_. The repair is really two parts: the bond
| that holds it together and the gold dust that covers the
| lacquer. The join bond can handle the dishwasher. The gold
| layer needs touchup every few years anyway, but it will need it
| a lot more often if it goes through the dishwasher regularly.
| Gold is expensive.
|
| There are some other ways of applying the gold that can hold up
| better, but they're less common.
| dlbucci wrote:
| This is awesome! The handle on my favorite mug broke off
| recently. I tried super gluing it back on, but it broke off after
| a few trips through the dishwasher (hand washing got old). I was
| gonna try epoxy next, but I try to avoid that stank whenever I
| can. Maybe I'll give this a shot.
| pjerem wrote:
| Repairing the handle can be dangerous. It means that your
| repair is going to support the entire weight of your mug + the
| (hot) liquid.
| tern wrote:
| I tried to order a kit with urushi powder from Japan recently and
| they had to cancel the order, saying it was now illegal to import
| into the US
| astrea wrote:
| I had no idea it was done with a resin.
| dudeinjapan wrote:
| I repaired mine with glue
| piyh wrote:
| I repaired my mug with epoxy and kept using it for years until
| the handle fractured at the same spot, dropped on my trackpad and
| shattered it.
|
| Now I get new mugs when one breaks.
| AdamN wrote:
| Is there a place that can do this for me?
| notdang wrote:
| If you are in US:
| https://www.lakesidepottery.com/Pages/ceramic-repair-and-res...
| silcoon wrote:
| Look better than new in my opinion
| roywashere wrote:
| When I was a kid I had a mug with my name on it that was gifted
| to me. My mother broke the ear off at some point and decided to
| glue it back on. A week later she handed me a steaming hot cup of
| tea and the ear tore off and I got severe burns on my leg as a
| result. Not great. As a result I am a bit wary fixing stuff meant
| to contain hot liquids
| pmarreck wrote:
| I think anyone would after that experience! Yikes!
| infecto wrote:
| Is it a good idea to use these as drinking vessels after repair?
| I always assumed the risk was too great. Even if you use some
| sort of epoxy over it, I would be concerned with contamination
| from the cracks not being fully sealed.
| 1970-01-01 wrote:
| This is once again a perfect use case for cyanoacrylate. There's
| FDA approved, food-safe brands that will simply allow you to
| rebuild every fragment into the cup. It will also cure into
| ceramic in under a minute. I say this because I've done it.
| You're wasting time and energy using any other method.
| akpa1 wrote:
| I suppose it comes down to if you're purely in it for utility
| or if you're trying to repair this thing of yours precisely
| because it's this thing of yours. I'd be far more inclined to
| go to the lengths discussed in the article for a precious mug
| that I've used for a decade than I would for a mug I'd had for
| two, even if I'd still want to repair both out of thriftiness.
| It's a labour of love.
| JoBrad wrote:
| Honestly, using CA is what I and many other folks would use, in
| this situation. I'm a huge fan of J-B Weld's Superweld light-
| activated glue. In the right lighting, you can see the steam
| puff from the glue when you activate it.
|
| But OP's process brings to mind the way we remember things: by
| reliving them in such a way that can (and usually does) produce
| a unique and slightly different product from the original. It's
| the investment of time, thought, and love that makes this
| process more desirable.
|
| I'm reminded of a recent comment thread on Jaloponik, where
| some great heads were talking about just _why_ the fact that
| anyone can go 0-60 in less than 4 seconds isn't actually a
| great as it seemed to be. I'm a nutshell it came down to the
| fact that this used to be the product of untold hours spent
| learning and iterating to eke out tenths of a second, over
| time, to finally reach that level.
|
| Admittedly it smacks of gatekeeping, but there is a fine line
| between gatekeeping and rewarding true mastery of an art.
| bee_rider wrote:
| Does it look nice? The aesthetic is part of the whole thing, I
| think.
| AJRF wrote:
| I think i'll try do this next time I smash a mug (maybe avoiding
| the Urushi lacquer as others have mentioned in this thread).
|
| It gives the mug so much character, looks better than before, and
| for sure it will be a conversation starter!
| oofabz wrote:
| This mug is well on its way to becoming a tsukumogami.
| bqmjjx0kac wrote:
| Did anyone else notice they pixelated their fingerprint in the
| "goldfinger" photo? 10/10 points for opsec.
| fellerts wrote:
| I was waiting for someone to notice that. Good eye!
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(page generated 2024-06-02 23:01 UTC)