26 



Hardwood Record — Veneer & Panel Section 



April 25, 1919 



The Ceaseless Search for Glue 



)ome 



New Materials Side by Side With the Old 



HE search for glue materials began a good many are waterproof at first, but long exposure dissolves them. 



thousand years ago, when the man who needed Laboratory tests are useful in detecting such glues before 



glue went out to find something of which to they are actually employed in important work. 



it. The search still continues, but the user There is a difference between cements and glues, and 



"orglue now buys his material in the market, and the hunt some materials put on the market as waterproof glues 



for somethmg new, or for new ways of mixing or apply- are really cements. As a rule they are of little value for 



ing the old, is left to specialists and scientists who make gluing wood; but investigators constantly bear m mmd 



that their business. New ingredients are found from time the possibility that a cement may be found that will be 



to time, but progress is still being made in the better equal to hide glue for wood. 



handling of the old ingredients, some of which were Fish glues, which are commonly sold in the liquid 



known ages ago. 



These materials are vari- 

 ous, and all have the com- 

 mon property of making 

 things stick together, but 

 they differ widely in some 

 of their characteristics. 

 Vegetable glues are com- 

 monly made by treating 

 starch with alkali, thus 

 making it more or less 

 soluble in water and giv- 

 ing it great adhesiveness. 

 Starch from the cassava 

 plant makes one of the 

 strongest vegetable glues. 

 It is employed in a number 

 of industries, particularly 

 in making veneer panels. 



Casein glues are active 

 competitors in the field. 

 The base is casein, and the 

 glue results when alkali is 



THE LAMINATED SHOE LAST IS JUST AS GOOD AS ANY AND 



GREATLY REDUCES THE TIME AND DRYING LOSS INVOLVED IN 



HANDLING THE THICK MATERIAL USED IN SOLID LASTS. 



(vScc article on p.Tge 2^.) 



form, are made from bones, 

 skins, heads, and sounds of 

 fish; but all liquid glues are 

 not fish glues. For some 

 kinds of work they are quite 

 satisfactory; but in joining 

 woodv/ork animal, hide or 

 vegetable glue is generally 

 preferred. 



Horns of cattle, hides 

 and bones of various 

 quadrupeds and scraps 

 from packing houses are 

 the materials from which 

 animal glues are made. 

 Much difference is likely 

 to exist in such glue, de- 

 pending upon the prevail- 

 ing material of which it is 

 made. Hide glue usually 

 rates higher than that made 

 from bone. It is impossible 

 to make high grade glue 



added. Casein is a product of milk. It looks somewhat from inferior stock. Decomposition is a serious fault, 



like "cottage cheese," and in fact, is nearly the same In the manufacture of animal glue, the stock is first 



thing; or it may be more nearly akin to malted milk. At washed to remove the dirt and grease, then boiled and 



any rate, it forms the basis of glue good for many pur- concentrated to a jelly which, upon becoming dry, is glue, 



poses, especially for waterproof work. Casein is said to Some users want a light colored, opaque glue, and that 



have been a Swiss discovery or invention, but it is now is produced by adding barium sulphate, white lead or 



an article of commerce and can be manufactured nearly chalk after the jelly has been concentrated but before 



anywhere. Shipments have recently come to this coun- it has cooled, 



try from Argentina. Long experience has taught glue users that the quality 



Some doubt has been expressed as to whether casein of glue bought in the market is uncertain, and methods 



glues are strong enough for hardwood joint work where of tests, almost without number, have been worked out 



strain is great; but it must be said of this material that it for trying them out. Nearly every factory employing 



has generally shown satisfactory results where the glue glue in considerable quantities has its formulas and rules 



has been carefully inspected and the application made for making necessary tests. The need of standards has 



properly. long been felt. It is easy enough to stipulate the qualities 



Waterproof glues are often made from other glues which glue must possess; but the purchaser is still under 

 by adding to them something to make them insoluble by the necessity of trying it out before employing it in par- 

 water, and formaldehyde or potassium bichromate are ticular work, because he cannot afford to take chances, 

 recommended for animal and casein glues. Some glues One of the principal difficulties in the way of estab- 



