[HN Gopher] Developing a food-safe finish for my wooden spoons
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Developing a food-safe finish for my wooden spoons
Author : alin23
Score : 45 points
Date : 2025-12-10 21:44 UTC (3 days ago)
(HTM) web link (alinpanaitiu.com)
(TXT) w3m dump (alinpanaitiu.com)
| bythreads wrote:
| Check out volvox and auro products
|
| Works well for me
| Dumblydorr wrote:
| Incredible analysis, great blog post! What's wrong with using raw
| wood? Will that go bad quickly?
| awestroke wrote:
| When the wood fibers get wet they swell and become soft. When
| soft, the surface will be very sensitive to damage. Fibers on
| the surface will raise and then not return to their original
| position, causing surface roughness. Repeated cycles of wet/dry
| will cause cracks.
| Saline9515 wrote:
| From experience, even the cheapest wood spoons won't bulge,
| as long as you don't leave them immerged in water for a long
| time.
| esperent wrote:
| Depending on the climate, it can go moldy very quickly.
| coryrc wrote:
| If you use the appropriate wood, you can wet and sand many
| times to get a smooth finish. You can burnish it (rub with hard
| metal) to close the surface well. But it will still stain and
| absorb smells, just to a lessor extent. You'll notice if you
| use the same spoon for coffee and tea, or the same spoon for
| curry and miso soup.
| convolvatron wrote:
| I don't have a problem. if they get a little funky I just sand
| them down. and let them soak in food-grade mineral oil for a
| while. same with cutting boards and butcher block tables.
| zkmon wrote:
| I always wondered whether the wooden spatulas and spoons they
| sell at IKEA are safe to use. I never know what that wood was
| treated with or coated with.
| vages wrote:
| Perhaps I'm naive, but buying from an IKEA (in Norway) or
| another big store feels less risky than buying something
| handmade.
|
| Several people are involved in making every product at IKEA. At
| least one of them must be an expert in compliance. They can
| expect scrutiny and product recalls, fines and bad sales if
| they're found out.
|
| The one person making the hand-made spoon does not necessarily
| know all the environmental regulations that should be followed.
| mbrock wrote:
| I think all wood finishes are "food safe" once they're cured.
| clickety_clack wrote:
| That is a terrible assumption to make. Lacquer for example
| does poorly under temperatures commonly encountered when
| preparing food and it's basically a mix of solvents.
| coryrc wrote:
| Dude already found the perfect thing, but wanted an excuse to
| play with random metallic driers and resins instead. Fine, but
| don't pretend it was necessary. But it's really
| hard to mix properly and apply on small wooden objects like
| spoons and cups. I almost always use too much accelerator,
|
| Just use a precision scale. Pharmacists give me side-eye when I
| mention cutting my medicine. No, I do small-scale epoxy mixing!
| kurthr wrote:
| You're apparently referring to Rubio Monocoat.
| mmooss wrote:
| > Some carvers use urushi lacquer which is the sap from a tree
| common to Japan.
|
| Urushi is the name of the Japanese tree, _Toxicodendron
| verniciflua_ (the genus formerly was named _Rhus_ ), and of the
| lacquer of which its sap is the main constituent.
|
| The lacquer is also called urushiol (note, not urush _oi_ l),
| which is also the resinous substance found in other members of
| the _Toxicodendron_ genus: _T. radicans_ and _T. rydbergii_ , or
| poison ivy; _T. diversilobum_ and _T. pubescens_ , poison oak;
| and _T. vernix_ , poison sumac. The resinous oil is what causes
| allergic reactions.
|
| Which finally gets to my point: What are the allergic affects of
| the tree, its raw sap, the liquid lacquer, and maybe for
| hypersenstive/reactive urushiol allergies, the finished lacquer?
|
| I don't meant to be alarmist - people have been eating off urushi
| lacquer for centuries. I'm thinking more about working with it.
|
| EDIT: For those interested in the scientific aspects of the
| resin, plants, and allergic reaction:
|
| Aaron C. Gladman MD. Toxicodendron Dermatitis: Poison Ivy, Oak,
| and Sumac. Wilderness & Environmental Medicine vol 17 #2 (June
| 2006)
|
| https://journals.sagepub.com/doi/10.1580/pr31-05.1
| esquivalience wrote:
| > Which finally gets to my point: What are the allergic affects
| of the tree, its raw sap, the liquid lacquer, and maybe for
| hypersenstive/reactive urushiol allergies, the finished
| lacquer?
|
| The Wood Database can be a useful practical site for this sort
| of thing. I found [0], a page for a different wood which is
| said to contain the same allergen:
|
| > The sap contains urushiol (the same allergen found in Poison
| Ivy), and can still be irritating to some sensitized
| individuals even after the wood has been dried, and sap can
| also seep through some wood finishes to the surface of the
| wood.
|
| Same as poison ivy? Count me out if true: I react badly.
|
| [0] https://www.wood-database.com/rengas/
| esquivalience wrote:
| Alin (OP), what a wonderful article. I've had the same problem
| and had given up experimenting for similar reasons to you. I'm
| now thinking to finish the cup I've half carved and have sitting
| on the shelf in the shed. Thanks!
|
| Your shop looks great too. Others might enjoy folowing the link
| buried towards the bottom of the article.
| chias wrote:
| Thank you for selling your version online!
| moron4hire wrote:
| I make wooden cups. I use water-based polyurethane out of a spray
| can to waterproof the interiors. I find it a lot easier to use
| than epoxy in almost every aspect.
|
| For the exterior and for cutting boards, I use a hard wax oil I
| make from linseed oil and beeswax. It's easy to prepare and I
| usually provide a small cup of it to whomever I'm gifting the
| cutting board.
|
| I reuse small, glass jelly jars with screw-on metal lids, about
| 1/2 a cup in size. You do need to leave a layer of water on top,
| though, because otherwise the top layer will polymerize and leave
| a rubbery layer you have to remove the next time you use it.
| dspillett wrote:
| Interesting, I'll have to give that a detailed read later. It
| might be applicable to 3D prints.
|
| To head off the people who will jump up-and-down calling me
| paranoid for not considering untreated printed works food safe,
| and accusing me of accusing them of poisoning family & friends
| (in some circles the discussion can get more cantankerous than
| the vi/emacs thing!): you keep using printed things for food
| without treatment if you like, and I won't judge, but I prefer to
| remain paranoid because if printed items were food safe it would
| be a selling point and I don't see any manufacturers using food
| based examples in their advertising.
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