You may have read a few weeks ago about what happens when Chris gets bored with watching me teach. And what happens a day later when people share “advice” after said experiments. As far as I know, the bugs have not yet eaten what is now Roy Underhill’s Dutch tool chest. (And frankly, I’m a little offended that some of y’all think my dovetail joints aren’t tight enough to keep the bugs out….)
I didn’t bring the chest home, but we did bring home the test joint Chris made with Gummy Bear Glue. On Tuesday, I tried reversing the gummy glue using the same strategies one uses to reverse hide glue; both are gelatin, after all.
But first, I hit the snot out of it…again. We first tried to reverse the joint using nothing but force (a big hammer) the day after Chris glued the two pieces together. It didn’t work then, either. But you see can above that this time, the lump hammer produced the start of a split. Under extreme force, the wood is failing before the gummy glue. Just as it does with hide glue, PVA and other wood-appropriate mastics after they’ve fully cured.
I cut the test joint into three pieces before testing the gummy glue reversal with hot water, alcohol and a chisel.
I boiled water, then as quickly as possible sucked it into a syringe with an 18-gauge needle and inserted hot water into the joint on all sides. After letting it sit for a few minutes, I was able to pop the joint apart with a sharp hammer blow. Just as I’ve done numerous times to hide glue joints treated with hot water.
As you can see, it’s an almost dead-clear reversal – no wood failure in the joint (that teensy bit of failure visible at the top of the above picture is where the split was starting from the untreated hammer blow).
Next I tried inserting 190-proof grain alcohol into the joint. This crystalizes hide glue – and it did the same here. I waited two minutes or so before smacking the joint, and you can see below that the split isn’t quite as clear as with the water, with a few thin areas of wood failure visible (again, the obvious failure at the edge is the result of before-treatment beating).
Then, I used a wide chisel to try to cleanly split the joint without water or alcohol. Same as with any wood glue, there is obvious wood failure – if not as much as I’ve seen with traditional hide glue.
Is two weeks enough set-up time – and in winter, where it’s too cold for the bugs – for a proper test of the gummy glue? Maybe not. But clearly, it has some holding power. Regardless, I am 100-percent certain that Roy’s Dutch tool chest will not fall apart; have you seen the number of nails I use on those things?*
* Maybe you haven’t…but soon, very soon, you’ll be able to refer to a book on the subject. Just trying to head that question off at the pass…
23 thoughts on “Gummy Worm Glue Update”
Good practical tests, I think. For the book, however, it might be interesting to take sample joints to a glue-lam lab and test them with a hydraulic press, to see the calibrated force needed for the joints to fail. One might even try different species of wood commonly used in furniture to see if there is a significant difference.
I was skeptical at first but… I should have invested heavily and cornered the market on gummy bears. Now there is a world-wide shortage and prices have sky-rocketed. Bright side? I can still get regular hide glue anywhere and anytime I want.
Megan, your mom said to stop playing with your food.
“My wife gave me a book titled The Complete History of Glue for my birthday. What was it like? Heck, once I picked it up I couldn’t put it down…”
When can we expect the book?
So, gelatin, a primary ingredient in most creatures in the gummy taxonomy, sets up like hide glue. Hide glue being a skin/connective tissue protein sort of concoction, and gelatin being a skin/connective tissue protein sort of concoction, I’m not surprised to be learning that gummy creature glue behaves much like hide glue.
Next up—boiled mollusk glue, maybe? Or—ooh, I kinda like this one—shedded snakeskin glue? Maybe mouse glue, made from throwing occupied mousetraps into boiling water, etc., etc.? Chitinous cricket/grasshopper glue? Or chitin glue made from boiling down the bits and pieces of lobster shell?Then there’s the boiled-down-chicken-stock glue, fish glue, and we’re back onto trodden ground. Does bouillon make a good glue? Hmmmm.
I think someone should apply for an NSF grant to study all this.
Shed scorpion chitin glue? I wonder if it’d still glow under UV light.
As an expert on absolutely nothin’, I’d be curious how the stuff would work if you mixed a little salt with the Gummy Bear solution to counter bug attacks.
Supposedstorely bugs don’t like salt.
Looking forward to the book. Do you know if other types of candy or desert work? Maybe custard or Cheesecake? Now that would be sweet!
Name of the book? The Strange Case of Dr Jello and Mr Hide. So big candy has been feeding kids hide glue all this time.
I like the way you think.
Thanks for the update on the book.
I was worried Bean might have eaten the manuscript.
As for the cheesecake comment from SteveV,
Google “Medieval Cheese Glue”.
It is actually a thing, and was water resistant once cured, so it was used for repairing ceramics.
The Cheese glue involves soaking “old cheese” in water for a few days, then mortaring the wet cheese into a paste, and mixing the cheese with an approximately equal quantity of quick lime.
I believe one episode of ‘Lovejoy’ involved repairing a chamber pot with a similar glue formula.
Next is which alcoholic beverages work best to crystallize the glue for separation of the parts. Just be sure to wait a few days before writing the blog post so you don shmuffelr tk dkmop.
You blinded me with SCIENCE! Thanks, Megan.
Absolutely brilliant to even make the mental connection. And then, to find out that gummy worm glue works nearly as well as hide glue is incredibly funny and oddly satisfying. I have to wonder about the cost of gummy worm glue versus hide glue …
The comment on Cheese Glue got me looking into it. I came across a monograph titled “A Practical Guide to Medieval Adhesives,” by Maya Heath. It describes how to make various glues, including hide glue, from scratch. There is a section on Gelatin Glues using Knox Gelatin that claims that gelatin glue is stronger than hide glue. There is history in those gummies!
Maybe everybody knows this except for me, but if alcohol weakens joints by crystallizing hide glue, is shellac (being alcohol-based) a poor finish for furniture held together with hide glue?
Excellent question. Pure guesswork, but I think a shellac finish would not penetrate deep enough, and the alcohol would evaporate too quickly, to have an adverse effect. But related: just today I went to the whiskey store to get some pure grain alcohol to make the 50/50 mix of ethanol and water to spray on my dovetails before I plane them flush. The dovetails are joined with liquid hide glue. I wonder now if I should use this concoction. I’d be applying it directly to the joints.
Evidence points to no – lots of pre-20th-century pieces around that used both. (Shellac sits on the surface – I don’t know of any typical application method that would flood into a joint and cause trouble.)
Partner with Mathias over at wood gears to test this against hide glue.
Just in case you missed it, this article got a write-up on Hackaday: https://hackaday.com/2022/12/29/the-sweetest-glue-in-the-world/
In my shop, i have a love hate relationship with that mechanical pencil in the headlining image.
Can’t wait to read the antpocalypse post. Wonder how long it will take them to render things back to parts.
Man you anthropomorphised the shit out of that glue.
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