WATERPROOF GLUE
Sometimes it is desired to use glue with waterproof qualities. Glue is rendered practically waterproof by adding a small quantity (about 1%) of ammonium or potassium bichromate to the glue liquid. Upon hardening, the glue then becomes waterproof. Adding a small quantity of formaldehyde to the liquid glue will help it to resist the action of water after it has dried for some time.
Others suggest dissolving glue in an equal quantity of water and adding about as much linseed oil as water, with the aid of heat, until a jelly is formed. This mixture is said to be practically waterproof.
A patented process has recently been put out for which the claim is made that it can be applied to any glue irrespective of grade or make, rendering it absolutely waterproof. The result is attained by mixing the glue with certain chemicals in specified proportions, and then adding a certain amount of formaldehyde. Any amount of glue can be treated and the process is said to be most effective.