To render glued joints waterproof, rub common chalk on the surface of the wood where the glue is to be applied, and then coat with ordinary glue in the usual manner. The chalk will protect the glue from moisture so that the joint will hold as well after being soaked in water as before. I tested this method some time ago and found that it works very well. W. S. Leonard.
A mistake not uncommonly made by infrequent users of glue is to break up dry glue in hot water. This is bad practice as the adhesiveness is greatly impaired. Always soak dry glue in cold water and then cook, but do not cook too long, as this is injurious also. Glue that has soured should not be used, and every precaution should be taken to keep it sweet if the best results would be obtained. M. E. Canek.
A glue cement that resists moisture is made by mixing with the least possible quantity of water 1 part glue, 1 part rosin and ¼ part red ochre.
Another glue which resists moisture is made of one pint glue melted in two quarts skimmed milk. Add powdered chalk to make it stronger.
A marine glue is made of one part of india rubber. 12 parts naphtha. Heat gently, mix and add 20 parts of powdered shellac. Pour out on a slab to cool. When used it has to be heated to about 250 degrees F. A. L. Monrad.
New Haven, Conn.
Take one quart soft water and 2 pounds of pale glue; dissolve in a covered vessel by the heat of a water bath, cool, and add gradually 7 ounces of nitric acid (specific gravity 1.335). This glue is very strong and will not gelatinize. C. S.
A useful fact to know in regard to glue when using it on furniture or other work that will be exposed to a very dry atmosphere, is that a small addition of chloride of lime will tend to prevent the glue drying out and cracking. The chloride of lime is strongly hygroscopic and constantly attracts enough moisture from the atmosphere to keep it moist. Use about one-fourth ounce of chloride to one quart of glue.
M. E. Canek.