January 10, 1919 



Hardwood Record — Veneer & Panel Section 



25 



Hen Makes Some Observations on Hot Cauls 



Dec. 23, 1917. 

 Dear Jim: 



Well, Jim, you know we came home on the twelfth so 

 as to have a few days to straighten up things at the house 

 before I went back on the job. We was going to spend 

 the night at the hotel and get the furniture we sent from 

 Chicago out of the freight house the next day. 1 sent 

 word to Phil Johnson when I'd likely be back, and when 

 we got off the train 1 got the surprise of my life. All the 

 veneer room bunch was there with Johnson and John 

 Malo and Ed Ford. They rushed up and shook hands, 

 and before we knew what was doing they carried us to 

 Ed's auto that was all tied up with pink and w^hite rib- 

 bons and had a big sign on the back "Welcome Home." 

 They pushed us in the auto and drove to the house and 

 carried us in. I was beginning to get sore at their fresh- 

 ness, but I got over it. What do you suppose that gang 

 done ? They had got all our stuff from the freight office 

 and fixed up the house. Some of the w^omen folks had 

 brought in some grub and the table w^as all set and v/e 

 all set down to a feed and had a regular party. The 

 bunch went home about nine bells. They had got to- 

 gether and made us a present of a big phonograph with 

 lots of records. 



I got your letter yesterday in which you ask what I 

 think about toothing stuff to be veneered. You say the 

 old man saw it done somevirhere, and has been talking 

 about it and thinking of putting in a toothing scraper. 

 Well, Jim, my private opinion is that toothing is all poppy- 

 cock, though I know some do it. You know all wood is 

 some porous, and that all that we use is plenty porous 

 to let enough glue soak in to give a good grip. Now 

 those that tooth say they do it to make grooves that will 

 hold more glue and give a better holding surface. But 

 it can't be proved that the more glue there is left between 

 the surfaces the stronger the joint will be, and I don't 

 believe it. I think that the closer the contact between the 

 surfaces of the wood the more strength there will be in 

 the joint. That is, depending on the kind of glue used 

 and the pressure applied to bind the surfaces together. 

 If you will get the old man to make some tests with you 

 by gluing up some pieces that have been toothed and 

 some that are nice and smooth, I don't believe he will 

 go to the expense of buying a new machine for toothing. 

 If the smooth joint is properly made it will be stronger 

 than the wood itself, and will break in the wood before 

 it will break in the joint. As long as this is so why should 

 we spend the coin to tooth stuff to be veneered? 



You say you had some argument with the old man 



about hot cauls, and he thinks you sometimes get them 

 too hot. Well, Jim, you're on the job and will have to 

 judge that work for yourself. You sure know that too 

 hot cauls will make lots of trouble. They will burn the 

 glue and destroy its sticking quality. And on softwoods 

 they drive the glue in so far that there is none left on 

 the surface to hold the veneer. Then you have panels 

 that the veneer will peel off easy. 



When I speak of burning glue, I mean to destroy its 

 sticking quality by some heating process, and you can 

 burn it with a caul as well as by too much heat in the 

 tank. Warm wood will take up moisture quicker than 

 cold w^ood, and hot water will soak into wood quicker 

 than cold water. So when hot glue is put on warm wood, 

 both glue and water in the glue soak in a little way, then 

 the wood begins to pull the water from the glue and 

 leave it in a nearly dry state. By putting on the hot 

 caul about this time the soaking up qualities of the wood 

 are made greater, and soon the glue is without protec- 

 tion of moisture and is at the mercy of the hot caul. Then 

 the glue loses its life and grip, and when the stock is 

 taken from the press the glue is brittle. A few hours 

 after being exposed to the air a knife blade ma}- be 

 pushed under the veneer and separate it from the core 

 stock. A too hot caul is the cause of the trouble. 



You sure know that too hot cauls make blisters, al- 

 though they are not the only things that make blisters as 

 I have written you before. So I say it is all right to have 

 warm cauls, but not hot ones, and if you are having any 

 trouble with loose veneers, or blisters, you better look 

 into the hot caul business. 



Well, Jim, if you get any more troubles for a while 

 don't w^orry if I don't answrer your letter quick, because 

 I'm going to have some of my own. That vegetable glue 

 outfit I told you about is here, and some bags of the 

 vegetable glue. If that stuff will stick anything I'm your 

 grandmother. I opened a bag. The stuff looks like so 

 much flour. I stirred some in a little cold water, and 

 some in some hot water, and the stuff it made wouldn't 

 stick paper on the wall. For machines there's two big 

 kettles and a spreader. The kettles are made of cast 

 iron, and there is a big paddle inside that has to be run by 

 a gear arrangement. I don't know what to say about 

 the spreader. I never saw one like it. I told the old 

 man about trying the glue, and that it was no good. He 

 told me not to w^orry because there was a fellow com- 

 ing from the company that makes the stuff to show us 

 how to get the machines in place and how to make the 

 glue. He is coming Thursday morning. Jim, I expect 



