Water Proof

I decided to put the concept of it to a test. I took one packet (.25 ounce) of Knox Gelatine (collagen extracted from animal parts commonly sold at grocery stores to make Jell-O) and emptied it into an old tuna fish can. I put about 3/8" of water - it quickly adsorbed all of the water. When heated it liquefied nicely. But, didn't harden rapidly and was rubbery week. I determined I had used too much water. Next batch was just enough water to cover the bottom of the can and added Knox Gelatine powder .25 ounce. This made a thick paste even when heated. It covered nicely and got rubber hard when first it cooled. Over 24 hours the glue got harder and harder, the surface of the excess glue that squeezed out of the joint felt harder than epoxy. Yet, the excess glue left in the can was still somewhat rubbery. I did a brake-apart test of two pieces of wood glued together after 24 hours and the wood broke .5" from the joint, the glue didn't break. Bottom line I think if the wood is dry this will work well. If a wet environment and wet wood then I think we will need to dry the wood (or item) before gluing it.

Offered by Mike.

Total saturation of the wood would soften the glue and cause a failure of the joint, but then so would most modern day white glues. Normal moisture should have no effect on the bond, but that will however depend on the degree of saturation. Even bonds joined by the new-technology glues suffer if the wood is poorly prepared or over-saturated with moisture. This could be minimized by sizing the surfaces with a weaker mix. Like a coat of primer, it seals the surface. Without it a thirsty surface may soak up too much glue, leaving the glue line starved and weak. Use slightly thinner sizing for dense wood, thicker for porous wood. Allow to dry and then apply the final thicker glue. Moisture prevention can then be minimized with after-treatment of the wood surface, i.e. oils, (there will be a plentiful supply of motor oil which makes excellent creosote,) animal fats or wax.

Any glue has its limitations depending on many factors. I do not claim that natural glues are perfect, in fact the data obtained is not my own, but based on the experiences of hand craftsmen that have built and maintained their own glues for a variety of uses. They in turn have taken information handed down from times of old when epoxy/super-glues just didn't exist. The glues in question worked back then so should work just as well today.

Offered by Brian.