24 



Hardwood Record — Veneer & Panel Section 



April 10, 1919 



CERTPg 



TRADEMARK Re&, 



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I Certus Cold Glue I 



j (The Original Water-proof Glue) | 



Joint Glue remaining liquid a | 

 full working- day after mix- | 

 ing. I 



1. Highest adhesive and wa- | 

 ter resisting quality. | 



2. In comparison lowest I 

 priced glue on the mar- | 

 ket. ' I 



I 3. Saves time, lahor, heat | 



I and trouble. | 



I 4. When mixed with cold | 



I water ready for use in | 



I 15 minutes. | 



I 5. Suitable for all outside | 



I gluing even in cold and | 



I wet weather. I 



I 6. A lay be used in jointing | 



I machines. | 



I 7. Cilues natural damp (not | 



I wet or green) as w^ell as I 



I dry lumber, steel, brass, | 



I stone, glass, linoleum, | 



I cork, cloth, etc., to wood | 



I and leather. | 



I 8. Stands all climates, even | 



I the most humid. | 



I 9. Especially adaptable for | 



I use in gluing hardwoods I 



I of all kinds. | 



i ^ 



I 10. Uniform government in- | 



I spected and sealed. | 



I Write for sample for testing on your special work. Our services | 

 I are at your disposal. = 



I CERTUS COLD GLUE CO. I 



I DETROIT, MICH. | 



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lating heat, humidity, air currents, and the like. Tlien the 

 behavior of the wood when acted upon by different 

 forces w^as shown. The kind of wood, its condition when 

 it goes into the kiln and its condition at various stages of 

 its progress, must be understood and watched; for if 

 left to chance, something serious may happen, no matter 

 how nearly perfect the kiln may be in its arrangement and 

 facilities. The kiln furnishes the machinery but it has 

 no brains. They must be furnished by the operator; and 

 perhaps the main thing of all is to so train the man in 

 charge of a kiln that he can both see what is happening 

 and provide a quick remedy, if needed, and know just 

 what the best remedy is. It is believed that therein lies 

 the principal secret of successful kiln drying. 



In the manufacture of furniture, and in making anci 

 handling veneer panels for other purposes, the manage- 

 ment of the glue is of first importance. The course of 

 instruction at the laboratory included lectures on glue 

 and experiments and tests in mixing and applying it as 

 it should be done to secure the best results. Proper kiln 

 drying is the first step, but it is only half, and following 

 that step comes the application of the glue to make strong 

 joints and satisfactory panels. The instruction at the 

 laboratory included discussion of kinds of glues and their 

 properties and uses; tests for viscosity, jelly, grease, 

 acidity, odor, decomposition, and, of course, the strength, 

 which is one of the principal considerations. The tests 

 for animal glues follow lines differing from tests for 

 vegetable and casein glues, and wherever the differences 

 may be of either advantage or disadvantage in a prac- 

 tical way, the points of difference are brought out and 

 emphasized. The sources of the various glues are ex- 

 plained, together with methods of manufacture. 



The course included lectures on and demonstrations 

 of ply^vood construction, including the effect of varying 

 the angle of grain of successive plies; and the effect of 

 the number of plies on the twisting and cupping of 

 panels. This was followed by discussion and tests of 

 the effect of varying the species of v/ood and the thick- 

 ness of the sheets, on twisting and cupping. Joints and 

 the methods of making them came in for practical con- 

 sideration. Defect in plywood is, of course, a matter 

 of much importance, and laboratory tests and demonstra- 

 tions were devoted to that phase of panel making. 

 Causes of defects and the remedies were carefully con- 

 sidered. 



Among the experiments carried out were tests of 

 specimens glued with animal and others with vegetable 

 glues, with the compilation of results for future refer- 

 ence. Similar work was done with casein and blood- 

 albumen glues. This was followed by the examination 

 and testing of plywood glued at different moistures and 

 densities. 



The last day of the two weeks' course was devoted 

 to clearing up points which seemed to need further dis- 

 cussion. Questions were asked and many matters were 

 reviewed. 



