|Curbside Delivery: A Ton of Glue!|
When I lecture about using glue for woodworking, I usually start in the 17th century. Although it is true that animal protein glues were used as early as the Egyptian times, traditional woodworkers in Europe up until the 17th century relied on mechanical fastening for their assembly.
First and most common were nails, which could be fashioned by the local iron worker, if you had the funds. If you were not able to buy nails then wood pegs would work. These pegs were not called "dowels" but rather "treenail, trunnel, or some variation of that term". When used to pull together a draw bore mortise and tenon joint they were quite effective. More useful is the fact that they could also be easily removed, as they were not glued, thus allowing larger pieces of furniture to be taken apart and moved upstair or across town, where they could be simply pegged back together again.
It was not really until ships began returning from overseas with more exotic timber than the usual domestic oak, walnut, cherry and beech. Harder woods, like ebony, would check and split when exposed to the climate of Europe. New methods were devised to saw these timbers into thin veneers, which could be then glued to a domestic substrate wood, combining the beauty of imported wood with the stability of air dried domestic timber.
These veneers, and the methods developed to apply them, created a new tradesman, the "ebeniste." This term was a direct reference to a woodworker who worked with ebony, and, as a logical extension, exotic wood sawn veneers. The golden age of ebenistes included such legends as Gole, Boulle, and Roubo. Without protein glues their craft would never have existed.
There are many different types of animal protein derived glues, and several varieties of each type are used for various specialized applications.
|Colle De Poisson or "Fish Glue"|
For example, fish glue is produced from different species of fish and different parts of each type of fish. Fish glue is normally liquid at room temperature and has a fairly long shelf life, at room temperature. You can expect it to remain useful for up to 5 years or more, depending on the quality of the glue. Fish glue is made and sold in Canada by Lee Valley and sold in the US by Norland Industries. Fish glue is what we use to hold brass, pewter, ivory, mother of pearl, horn, and other non wood materials to a wood substrate. Fish glue cleans up very easily with cold water. It also has a very low sheer resistance to creep, which allows the non metal elements of the surface to remain stuck as the wood substrate expands and contracts during environmental fluctuations. Toothing the metal (on the glue side) and rubbing the surface with a fresh clove of garlic prior to applying the glue is the traditional method.
|192 Gram Hide Glue and Traditional Glue Pot|
Animal hide, connective tissue and ligaments, and animal bones are generally cooked until they become a glue. Hide glue is used by itself, bone glue is used by itself, and blends of the two are also used in woodworking, usually 1/3 bone to 2/3 hide. Hide glues are graded using a Bloom gelometer, which is an interesting tool. You should Google it and see for your self. It is important to note that these glues are sold in a "gram strength" number which ranges from around 50 to 500. The confusion is that people imagine the higher gram strength number indicates a stronger glue. This is false.
All grades of hide glue have adhesive strengths which are comparable. The difference is that the lower the gram strength the slower the glue sets and the more flexible the bond. The higher the gram strength the faster the glue sets and the more brittle the bond.
I buy all my protein hide glue from Milligan and Higgins. If you have questions, I encourage you to call them directly. Milligan and Higgins Use extension 18 to talk with Jay Utzig, my favorite glue chemist. If he is not fishing, then he is at work.
The use of a traditional double boiler glue pot is no longer in fashion. I use one in my shop, and have done so for nearly 50 years. I turn it on when I arrive and the last thing I do when I leave is turn it off. I have many videos on my YouTube channel ("3815utah") talking about using this glue, as well as the excellent videos posted on WoodTreks: Using Animal Protein Glue
|Processed Glue vrs Organic Glue|
When I researched methods to modify protein hide glues by lowering the gel point, I eventually developed a formula which I began selling as Old Brown Glue. It has been nearly 20 years that this glue has been available and the demand is growing exponentially. I knew that if the glue worked like I thought it did, then every woodworker who discovered it would tell two of his friends. By this method the word of mouth has created a demand that requires me to cook hundreds of pounds of glue each month. Lots of bottles, caps, labels, boxes, shipping labels, billing and so forth. Old Brown Glue has become a business on its own and has exceeded my modest expectations.
I have been asked by luthiers if Old Brown Glue would work for their instrument construction. I know that luthiers understand qualities of different glues better then furniture makers, and I believe that there is a real application for liquid glues, in addition to hot glues, depending on the project. Years ago I was approached by one of the most famous guitar makers in America. They wanted to test my glue to see if it would work in their production run. They were making a special 50th anniversary edition of their signature guitar and were instructed to use methods and materials which were as close as possible to the original. I sent them glue and they tested it for two years. Finally they decided it worked perfectly and began ordering a lot of glue.
I repeatedly called them to ask permission for posting on this blog, using their company name. I must say that the legal department of the guitar business is much more difficult to have a conversation with compared to the production line workers.
In any event, no response. Thus, in trying to avoid any direct legal conflict, I will merely post this YouTube video, which I found online: Guitar Factory Tour I think you will be interested in the glue used at the 2 minute mark. I would also like to post here one of my favorite guitars:
|Favorite Guitar Patent|
There is another type of protein glue, rabbit skin glue.
|Rabbit Skin Glue|
I created this simple chart for understanding protein glue:
|Temperature vrs. Humidity|
Hide glues and their working characteristics are a function of temperature and hydration. Dry glues are first hydrated with cold water, approximately 50/50. The better quality the glue the faster it will absorb the water. Then the hydrated glue is heated to around 140 degrees where it becomes liquid. Glue can be heated and cooled as many times as you want, as long as the temperature does not exceed 180 degrees.
Animal hide glue, both Old Brown Glue and Hot Hide Glue, is unique in that it can be in various states (solid, gel, liquid) without damaging the quality of the glue. It can be repeatedly frozen, thawed, heated, cooled and so forth as many times as you want, as long as it doesn't get moldy or heated to the boiling point. The same process used to mix it (add cold water and then heat) reverses to cure it (loss of heat and then loss of moisture.)
The rapid loss of heat in hot glue makes it perfect for a fast tack. Then, more gradually, it looses moisture into the wood and into the environment, for a full cure. Old Brown Glue takes much longer to tack, so it has a much longer open time. It then cures more slowly as it looses moisture much more slowly, achieving a full cure in a matter of a few days. Both types of glue create an equally strong bond.
Why not try some of my Old Brown Glue today? After all, I make it fresh every day. I will leave you this email, one of many such emails I receive every day from satisfied users of OBG. I asked Dave for his permission to copy this message. He said it would be fine with him.
This Just In! It seems that Popular Woodworking magazine is out with an informative article by Christopher Schwarz called "The Best Glue for Furniture?" He discusses liquid glue and you can either pick up a copy or click here for a taste: Popular Woodworking Magazine: Glue