After making a test joint with Haribo Gummy Bears, I let it sit overnight then subjected the joint to all sorts of abuse with a nail hammer. The joint held as well as any joint I’ve made. And the red squeeze-out had turned from a jelly to rock hard.
So Megan Fitzpatrick agreed to a real-world test: Gluing up a Dutch tool chest with Gummy Glue. I bought some less expensive gummy worms (59 cents) at the gas station up the block (I also got some lovely Indian food there). I melted the worms into the goo left from the bears and added a bit of water until the mixture was like good hot hide glue.
Together, Megan and I glued up the carcase. I was a little worried we would run out of glue because Roy Underhill and the other students kept sampling it.
Bam, bam, bam. And the case went together. We put clamps on it and let it sit.
Some observations: the stuff sets up slower than traditional hot hide. It took an hour for the gummy squeeze-out to gel to the same point where the hot hide gets in 30 minutes.
But after sitting overnight, the gummy stuff was hard as glass.
After posting our original experiment here and on Instagram, we got a lot of comments saying things like: The glue won’t hold. It will only last a couple seasons of moisture exchange. You’ll get ants. Bugs will eat the glue.
To all this I say: Shut up. You don’t know. You just love to hear your tongue rattle in your cake hole.
The finished tool chest is now owned by Roy. He’s going to fill it with his favorite tools and leave it to his daughters. If you really want to know how the glue fared, ask them in 50 years.
Along with blue tape and paper towels, so-called “super glues” are often cited as a way to treat relatively minor cuts in the workshop. But the cyanoacrylates that are meant to glue wood, porcelain and plastics (and hardhats to I-beams – if you’re old enough to remember that Krazy Glue commercial) are actually harmful to your skin. Dr. Jeffrey Hill, author of “Workshop Wound Care” (who is an emergency room physician and a woodworker), explains the difference.
Find out what else you should have on hand in you shop’s first aid kit – and how to use it – in “Workshop Wound Care.”
“Roubo on Furniture” is filled with insights into working wood and building furniture that are difficult or impossible to find in both old and modern woodworking books. Unlike many woodworking writers of the 18th century Roubo was a traditionally trained and practicing joiner. He interviewed fellow craftsmen from other trades to gain a deep and nuanced view of their practices. He learned to draw, so almost all of the illustrations in this book came from his hand.
In addition to the translated text and images from the original, “With All the Precision Possible: Roubo on Furniture” also includes five contemporary essays on Roubo’s writing by craftsmen Christopher Schwarz, Don Williams, Michael Mascelli, Philippe Lafargue and Jonathan Thornton.
As far as the manner of joining panels, after they have been dressed or smoothed, according to whether they are more or less thick, you begin by trimming them and making them equal width, observing to eradicate all types of sapwood, knots and splits, after which you set them up according to the different widths that they should have. You should take precaution to put the planks of a similar color together, the narrowest (which we name alaises) in the center [of the panel], and the edges of the plank that are softer [wood closer to sapwood] should be used in the groove joints [in the frame]. After they have been thus set up, you begin making the joints by cutting the grooves, then you make the tongues. After having taken the precaution to position the plank where you have made the groove against where you wish to make the tongue, to see if both of them are truly straight, then you make the tongue. When the wood is thick, you trim the back of the tongue by chamfering [it] with the half-plane [ jack plane], so that the plane [the tongue plane] is easier to push. When the wood is rough and very thick, you need two workmen in order to push it, as I said in speaking of planes of two pieces, but the more it can be done by a single workman, so much the better for the work.
It is also necessary to take care that the joints be straight on the edges of the panels and that they fit equally on each side of the groove, even when the work is just a facing [a decorative panel, not structural]. Joints thus well brought together prevent the air from penetrating and, consequently, from warping the panels.
After having made the joints with all the precautions that I spoke about previously, you glue them together; and for this, you disassemble the boards from each other, after having numbered them, so as not to confuse the panels of one panel with those of another. After this, you heat the joints so that the heat opens the pores of the wood, preparing them better to take the glue and hold on to the joints. It is necessary, however, to pay attention that the wood not be too hot because it will dry the glue too promptly and prevent it from holding. As for the glue, it cannot be too hot [in other words, the hotter the glue, the better] because the heat makes all the glue components finer and delicate [less viscous] and consequently better to penetrate in all the pores of the wood.
The glue that Joiners use is called hard glue, which is of two types, namely that of England and that of Paris. These two types of glues are made with the sinew and feet of beef that you boil and melt into gelatin, after which you mold it into sheets of 8–9 feet in length by 5–6 in width and 2–3 lines thickness. When it is completely dry and it is of a good quality, it is both hard and also fragile as glass. That from England is the best, not only because it makes half again as much profit, but also because it holds better and its color being a clear yellow means that is does not appear in the joints when they are well done. You also have the glue of Paris that is not so strong, is black and muddy and it always shows in the joints, no matter how well made.
When you wish to melt the glue, you begin by breaking it in little pieces and you put it to soak in some water for 5–6 hours, after which you melt it on a fire in a copper cauldron.
You must observe not to put [in] too much water at first because it will remove some of its quality. You must also take care to stir it up with a wooden stick while it is melting, and when it is completely melted you let it boil on a low fire so as to make it re-heat. You should never leave the glue unattended once it begins to boil because at this time the force of the heat makes it froth and boil over out of the cauldron, which you prevent by adding a little fresh water when it is ready to boil over. The glue is easy to spoil and becomes tainted while you are melting it. That is why this task is best left to one individual man.
Dry glue is sold by the pound, and woodworkers who have a lot of work take care to provision it so that it always remains dry [unspoiled]. When you wish to melt it, you should take care not to melt too much at once, that is, you must not have melted more glue than you can use in eight days, especially in the summer because it molds and loses its quality. You heat it in a copper pot, which has three feet and an iron handle. The feet should be splayed to give it a stable position, but [they should] not [be] hooked and elevated at the ends because being thus configured [the cauldron] is subject to carrying some of the hot coals with it and to making [coals] fall in the wood shavings [when moving the cauldron around the shop], which is greatly to be feared. Cabinetmakers use a double-boiler pot, in the outer chamber they put the water and the glue in the inner one. This way of heating the glue is called a bain-marie [hot bath] and is very convenient because the water being very hot maintains the heat of the glue longer, while preventing the glue from burning at the edges of the pot, Figs. 12 & 13.
When the glue is hot, you spread it on the joints with a brush made of wild boar hair, which should be more or less large according to different works. Look at Figs. 14 & 15. Then you drive the joints together with a mallet. When there are many joints [complex joinery with many joints being assembled simultaneously] and you fear ruining them with the mallet, you turn them over and hit them on the bench, lifting first one end of a panel and making it fall straight with force on the bench. Then you do the same at the other end, which you continue to do until the joints are perfectly in place. Then you put them flat on the bench where you stop them using a bar/straightedge of the full length of the panel [that is] secured with holdfast, and you tighten the whole panel with clamps or on edges with clamps and bars, which holds them all along their length and closes them. Bar clamps are iron tools which are made of a bar of iron where the end is curved in the form of a hook, which passes through another piece of iron which is called the foot of the clamp, which glides along the length of the bar according to how you judge appropriate. The end of this clamp is curved in the form of a hook, as is the other end of the bar, and is textured at the face like a rasp, so that it [will] not slip when you tighten it but it [instead] holds onto the wood.
The mortise or eye of the jaw should be as accurate as possible, especially on its width, and be made a bit slanted on the inside of the foot on the side of the hook, so that when the bar clamp is tightened, the foot will always be at a right angle to the shaft, as least as much as possible. The end of the shaft/bar is hammered back to create a ridge [is “mushroomed”] so the hook cannot get past or get lost. Like most of the regular clamps you cannot remove the moving foot, Fig. 16.
This tool serves to hold the joints for both panels and for assembled pieces. You close it by hitting on its movable foot with a mallet below the bar, and you loosen it by hitting the latter on top with the hammer, that is to say, in the opposite direction. [It operates in a manner conceptually identical to the holdfast.]
The length of the bar clamps varies from 18 thumbs up to 6 and even 8 feet in length. As for the width of the bar, it should be from 9 lines up to a thumb-and-a-half, according to the different lengths, and their thickness should be two-thirds of the width. The foot should exceed the upper part of the bar by 3–4 thumbs for the smallest, and from 6 thumbs for the largest. The iron of the bar clamp parts should be soft and without any type of welding, especially the foot, which should be forged with all the care possible.
It is good that joinery shops be well furnished with bar clamps, especially those shops with many workmen, which is very convenient for accelerating the work. There are shops where there are up to 20 lengths of bar clamps of all sorts. When the work is of such great width that one cannot close it with bar clamps, you use a marking rod of wood, which is called a notch for elongating sergeants [bar clamp extender], which is 3–4 thumbs in width by 8–9 feet in length and a thumb-and-a-half thickness at least. At one end is made a hook, made equal to the width of the wood, which serves to close the work. On the other side of its width, and in the opposite direction, are many notches placed at 12–15 thumbs from each other, in which you place the end of a bar clamp, which is tightened on the other edge of the work. You must pay attention that the notches are made at a sharp angle, so the bar clamp jaw stops there and does not come out, Fig. 17.
There is still another way to clamp panels, which is done with wooden tools called straighteners [ from the verb etreindre, or to close tightly]. They are composed of two of pieces of wood called twins of 4–5 feet in length by 4–5 thumbs in width and 2 thumbs thickness, in which [at] 6–8 thumbs from the ends is pierced a squared mortise of about a thumb-and-a-half, which is in the center of its width, and through which you pass a shaft of 8–9 thumbs in length.
In the upper part of straighteners are pierced two or three other mortises similar to the first ones through which you pass another shaft of the same shape and length as the first one, Fig. 18.
When you wish to make use of straighteners to clamp a panel, you begin by placing [the parts] between the two twins, resting the panel on the lower inserted shaft. You then press the twins together to hold the panel flat. You then insert the shaft through the mortises above and closest to the panel, and with a mallet drive in a wooden wedge between the panel and the shaft.
There must be two straighteners at least to clamp a panel, and when it is long enough, you really should make use of three. Besides, the use of these tools is excellent, because they clamp panels without damaging them, which happens sometimes with bar clamps. But still, they hold the panels very straight, and they leave you the liberty to view them from both sides, which you cannot do when the panels are laid flat on the workbench, Fig. 19.
By A.C. Horth, from “The Woodworker,” January 16, 1905. (Thank you to Buz Buzkirk for the generous gift of two fascinating early volumes!) NB: I would not read this excerpt while eating breakfast.I might not read this excerpt at all if you are a vegetarian or vegan.
We are told that glue is made from hoofs, horns, and other animal refuse, and many of us are quite content to take this explanation as it stands. But the more inquisitive woodworker, who likes a fuller description of things, will, perhaps, find the following account of the various processes in the manufacture of that substance with which he is so familiar, interesting.
The writer, a short time ago, accompanied by a camera and note book, journeyed to Bermondsey and soon located the works of Messrs. B. Young & Co., Ltd., by the odour of decaying bones. On entering the gates of the factory, the first thing the eye encountered was heaps and heaps of bones, horns, and fleshings (the latter are odd corners of hides which are useless for making into leather).
This refuse, continually being brought in by wagons, is sorted and arranged in different heaps, the fleshings being carefully picked out for making the best glue and size, the bones and hoofs being used for making glue of inferior strength.
The most striking point about a glue factory is the absence of waste. One might say that every particle of the material which enters the factory is used up in some way and has a certain value; and, considering the fact that the glue makers utilise the refuse of the tanners, it is astonishing to an outsider to see how everything is accounted for.
We see many instances of the care which is exercised to avoid waste, before the glue is extracted from the offal. This is particularly apparent in the case of fleshings, which are overhauled and all pieces with hair or wool attached treated separately in order to detach and save these useful materials. Such hair and wool is dried, cleared, and packed into bales, to be eventually used by the blanket manufacturers, in making a cheap variety of rug.
The fleshings are placed in revolving drums and thoroughly washed with lime; the drums being fitted with racks which keep the fleshings in continual movement. The next stage carries them through the curing vats, where they are thoroughly impregnated with acid to remove the lime and render them fit for the boiling pans. Under the influence of steam, the gelatine is dissolved, leaving a very small proportion of refuse. This process is continued until there is no trace of glutinous substance in the fleshings. The liquid is run off into coolers, oblong boxes, in which the glue is allowed to set.
When the glue is set, it is divided into two cakes and placed on a table, and, by means of a wire, cut into slices, placed on a frame covered with netting, and taken to the drying sheds to harden.
We have yet only considered glue-making from fleshings; we have still the heaps of bones and horns to account for, so will now describe the process they undergo. A glance at the bones will show of scraps of dried flesh adhering to them, which are no use for making glue; yet these are by no means wasted. The bones with the attached flesh are placed in heated drums, fitted with revolving wires, which tear off the flesh, leaving the bones quite clean. This dried flesh, now in the form of dust, makes a valuable manure, and is packed into small bags.
The bones are next placed into a large cylinder, the glue is extracted under high pressure, and finally, when quite finished with, are ground up, and form another bye-product, namely bone manure, for which there is a great demand.
Continuing our tour through the works, we pass through the size room, where hundreds of small barrels are being filled with a bright golden liquid. This is size – the size for which this firm is so renowned. It comes from the fleshings, and great care is bestowed upon its manufacture to get it to a uniform strength and colour.
We next look at another room, in which the oil (which, naturally, is extracted with the glue) is refined. Here is another example of the way bye-products are utilised. Another room is devoted to the manufacture of concentrated size, which is a specially-made and strong form of glue ground up into a powder. Amateurs will find that to buy concentrated size is better than buying ordinary glue, as it keeps well in the packets, and is more convenient to use than the large cakes of glue.
We had a look at one of the large drying sheds, open on all sides, but fitted with hundreds of racks, containing cakes of glue, which, when thoroughly hardened, are washed and packed up ready for market.
In passing through the works, it was impossible to avoid noticing the great care bestowed on the manufacture of the glue in all its stages, and, considering the dirty nature of the work, the neatness of the various departments impressed us greatly. The writer is greatly indebted to the Management for their kindness in allowing him to visit the works and take the necessary photographs, which, in many cases, caused considerable inconvenience.
A wedged through-tenon after the gelled glue has been removed.
In 2018, I shared this trick that David Savage used to improve dovetail joints. He called it “Juicy Lucy,” and it involves flooding the exterior of a joint with extra hide glue to swell the fibers and improve the joint cosmetically.
We continue to use his trick with dovetails with great success. And at some point I started using it with the wedged through-tenons on my chairs. Here’s how I do it.
Applying glue around all show surfaces of the joint before wedging.
After I glue the joint and assemble it (but before wedging), I paint a thick coat of glue around the show surface of the joint. Then I paint glue on the wedge and knock it in place.
Once the glue has gelled, I remove the excess with a dry rag and let the joint continue to set up overnight.
I’ve been real happy with the results.
— Christopher Schwarz
What the glued tenon looks like just before wedging.
