'v: gogagm^;!;ti;^.\^ma^?m:/:ia:^»B:!;^^ 





^A/^hat Veneer Users Are Learning I 



Perhaps tbo iiiobt inipoitant lesson tliut has been learned by the 

 veneer-using public during the past few years of general discussion 

 and rapid progress in veneer work pertains to the use of glue. They 

 have learned that to get the best results from glue it should not be 

 heated beyond a certain temperature. That temperature limit has 

 been gradually lowered from time to time and now stays between 

 140 and 160 degrees F, with 150 being pretty commonly used as a 

 central point or working average. 



Formerly the idea of cooking glue did not take into consideration 

 tlie effect of temperature, and it was pretty generally assumed that 

 so long as the glue pot or heater was protected from direct contact 

 with fire by being inserted in an outer casing with water between, 

 there was no chance to scorch or overheat the glue. This was a 

 common error that prevailed a long time in connection with the use 

 of glue, probably because in the early days when glue pots were set 

 on stoves the temperature was seldom high enough to do mucli 

 ilaniage. 



Kxperimeuts of the analytical class have long since proven con- 

 clusively that water can be heated to a temperature of 212 and that 

 steam is something above that temperature, and in each case the 

 temperature is high enough to do serious damage to glue. This mat- 

 ter has been elaborated on so much in discussion the past few years 

 that there is little need to go into exhaustive detail now. Glue 

 should be prepared and used at a temperature between 140 and 160 

 ilegrees F, and every glue user should liave a thermometer so that 

 he can know positively at all times just what temperature he is 

 maintaining. 



Another lesson learned is that repeated heating of glue or the 

 carrying over till the next day surplus glue from the day's work is a 

 bad idea. Glue carried over from one day to another deteriorates 

 :il)out fifty per cent in value and if mixed with fresh glue the next 

 (l;iy simply reduces the value of the fresh glue instead of proving a 

 means of economy in the glue room. Every user of veneer should 

 figure out his day 's requirements ahead and never make up any more 

 glue than will be used up. He can at least keep it down to the point 

 where at the end of the day he can afford to throw away 'whatever 

 glue is left and have a nightly dish washing by cleaning up his pots 

 and pans. 



Following the discovery by analytical expeiiments of the right 

 temperature at which to use glue and the need for fresh glue every 

 day, there has naturally come quite a number of tests and analytical 

 experiments with glue itself to determine just what glue is best and 

 most economical for any given purpose. This idea has been followed 

 out by so many people, in so many different directions, with so much 

 elaboration, that it is almost impossible to keep up with it. Those 

 who try to follow it out in all the finer points meet confusion about 

 as often as enlightenmet. Perhaps the veneer using trade has been 

 following this idea to extremes just, as manufacturers have at times 

 gone to entangling extremes with ideas of system and efficiency. Ex- 

 tremes of this kind are justified in many cases but they are apt to 

 prove disappointing to many others, and to bring reaction just as 

 extremes in fashions result in the abandoning of given fashions and 

 taking up of something new'. 



One may, by a series of experiments, determine just what class of 

 glue and what quantity and what percentage of water may be best 

 for a given kind of work. This is enlightening, but let us say that 

 the study and experiments have been conducted with a view to 

 determining what are the best and most practical solutions to use 

 on oak. So far so good, but the veneer user may have oak face 

 veneer and he may have a core body made up of chestnut, gum, poplar, 

 pine or any one of a dozen different woods. Any of these other 

 woods may go best with some other glue solution that differs con- 

 siderably from that being used. 



The thing for every veneer user to do is to take the new theories 

 and things learned about glue and glue-using and see how he can 

 make practical applications of them iu his own particular work. The 

 work of veneer-using differs so radically iu different institutions that 



it is hardly practical to lay down many general rules or formulas 

 aside from those of temperature and cleanliness and things of that 

 kind. The exact kind of glue and the mixture with water are things 

 that each man must determine for himself. Then, once he determines 

 it, there is the matter of maintaining it without going to too much 

 trouble. 



Uniformity in glue mixture for a given kind of work is an important 

 thing. Once a man has determined the percentage of moisture that is 

 best for a given work, it is up to him to devise simple ways and 

 means for maintaining the standard of this solution all through the 

 day and day after day. There are several ways of getting at this. 

 One is by weighing the glue and using a certain amount of water to 

 a certain amount of glue by weight ; another is by measuring both the 

 glue and the water. Each of these may err a little bit. Weighing is 

 usually considered the most reliable, yet a given quatity of glue may 

 weigh a little more on a damp morning after a soggy, rainy night 

 than it would weigh during an excessively dry period. The variation 

 here, however, is perhaps less than would result from efforts to 

 measure. So the best jilan would seem to be to establish a schedule 

 for mixing a certain quantity by measurement of water and weight 

 of glue. 



This is really nothing but a^ reliable starting point, however, and 

 one should use common sense and judgment in passing on the glue 

 mixture after it is heate;! and re.idy to use and as to the thickness 

 or thinness of the iiijuiii which, put into technical terms, would mean 

 the viscosity. This calls for iiuother instrument as well as a glue 

 thermometer, if one would be strictly accurate in the matter. It is 

 an instrument that is advisable to have around. In practice, however, 

 one can judge pretty -ivell the fluid state of the mixture by pouring it 

 or by watching how it works with the machine or spreads with a 

 brush. Carefid watching of this and a diligent use of horse sense as 

 well as science and instruments will insure satisfactory results right 

 along. 



When a veneer user becomes puzzled about his experiments in this 

 line and about what constitutes the best practical mixture an excellent 

 thing to do is to call in for consultation a representative of some 

 live glue manufacturing concern, or exjilain to the glue manufac- 

 turer just what work he is doing and ask for advice. Glue manu- 

 facturers have experts who make a study of all phases of veneering 

 and glue-using, and they are generally in a position to give reliabl-j 

 advice and useful information. They are glad also to furnish it to 

 customers and prospective customers. This is the place for tho 

 average veneer user to get his best information. Of course there 

 are institutions using enormous quantities who can afford to have 

 chemical experts of their own to test and analyze glue and conduct 

 all necessary experiments to get information of this kind for them- 

 sehes. Others can get it without so much expense by calling in tiio 

 glue people to cooperate -nith them in the study and experiments. 



One of the things we thought we had learned about the glue room 

 that seems to be proving a mistake in the final analyses, is the mat- 

 ter of temperature at which the glue room itself should be kept when 

 using glue in laying veneer. The theory was advanced that if it 

 were practical the ideal thing would be to have the temperature of 

 the room itself pretty close to the temperature at which the glue is 

 heated. The theory back of this was there would be less chilling and 

 settling of glue before the work could be fitted together and put into 

 pressure. The final analyses is proving this theory to be in error. 

 It is found that excessive heat in the glue room creates an unstable 

 moisture condition. The air in the glue room from being heated be- 

 comes hungry for moisture, so that often it will take up moisture 

 from the glue that is spread and thus cause a drying out and a 

 setting quicker than when using a temperature not so high. This 

 fault of course might be corrected by supplying more moisture to the 

 heated air, but that would make it decidedly uncomfortable to work 

 in. Anyway, the final analyses show ttat a temperature of something 

 like 70 degrees F. is about the best for the glue room, and this is 

 the temperature that is alMut the most comfortable for human 



