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Hardwood Record — Veneer & Panel Section 



May 10, 1917 



Conditioning Veneer Blocks 



Need of Investigation Into the Boiling and Steaming of Wood Before Con- 

 version by Machines 



HE COMING OF SUMMER WEATHER and the 

 trade entering into what might be termed the 

 cold cutting season, when several kinds of wood 

 are cut on rotary veneer machines cold instead 

 of boiled or steamed, is a reminder in a way that we have 

 never really developed the conditioning of wood for cut- 

 ting to an exact science. We have reduced artificial dry- 

 ing to something of an exact science, and have means 

 of testing not only for dryness but for temperature and 

 moisture records of a definite character which are doing 

 much to eliminate the element of guesswork in drying 

 lumber. In many lines of effort we are reducing things 

 of this kind to an exact science, but in preparing veneer 

 blocks and flitches we still follow guesswork and old rule 

 of thumb methods instead of getting busy as we should 

 and reducing this to an exact science. 



We know in a general way that in certain conditions 

 wood will cut easier on a rotary machine or a slicer than 

 in other conditions. We know that during the summer 

 some woods like poplar, cottonwood and basswood, will 

 cut very well cold and even if they must be steamed or 

 boiled, they require a much shorter time in preparation 

 than some other woods. 



On the other hand, we knovif that some w^oods must be 

 steamed or boiled to soften them and render them pliable 

 for cutting, and that sometimes boiling works better, some- 

 times steaming, and sometimes either one may be over- 

 done and make more difficult the cutting they are sup- 

 posed to make easier. We know a little more about these 

 things than we did twenty years ago, and more people 

 know about them, but in the matter of reducing it to an 

 exact science we have not made much progress in a twenty- 

 year period. 



Back something like twenty years ago, more or less, the 

 boys one day rolled out of the veneer cutting room of the 

 St. Louis Basket and Box Company into the sawmill a red 

 oak block about six feet long which apparently had just 

 been put into the veneer machine and rounded up nicely. 

 Inquiry as to why this was being passed into the sawmill 

 brought the statement from the peeler boss that it was so 

 blamed woolly they couldn't cut it on a veneer machine 

 and they were going to let the sawmill have a try at it. 



We had been wrestling with some pretty tough and 

 woolly propositions in cottonwood in the sawmill depart- 

 ment and were inclined to smile at the idea of a short oak 

 log that would make difficulty as compared to these, be- 

 cause we had never encountered any oak that had given 

 serious trouble to the sawmill. But when we loaded that 

 block on the carriage and started to convert it into thick 

 planks for cutting into Briggs basket splints we encoun- 

 tered trouble that brought to mind an old sing-song tune 



about the goose that broke the sawmill's teeth off. That 

 short log block was so tough and vsfoolly that we had all 

 kinds of difficulty before it v^^as converted into plank 2 ^4 

 inches thick, and the surface of these planks showed a 

 hairy or w^ool-like coat suggesting the need of shearing. 



During the noon hour the writer had a session v^rith the 

 peeler boss about that red oak block, and the whyfore of 

 its toughness, in which it developed that they had found 

 it in the bottom of a vat where it had evidently been over- 

 looked for a week or more and had been through all the 

 successive daily boilings of that period. This successive 

 boiling was what made the trouble because similar oak 

 blocks given from twelve to twenty-four hours of treat- 

 ment were being cut without much trouble. 



This, so far as the writer knows, is the most drastic 

 demonstration of how^ excessive boiling or steaming may 

 toughen wood and make it difficult to cut. Other expe- 

 riences have demonstrated that by making the boiling 

 severe enough and carrying it on long enough the wood 

 structure can be broken down and the timber literally 

 boiled away. This gives us a sort of general knowledge 

 that a certain amount of heat and moisture will soften 

 wood, make it pliable and easier to cut, but if the boiling 

 is continued longer there is a period in which the wood 

 toughens, becomes woolly and following after this with 

 hard enough boiling comes a period of breaking down and 

 disintegration. 



We had learned this more than twenty years ago. We 

 have learned through practice a good many things since, 

 yet visits to veneer plants and their boiling vats and steam- 

 ing boxes these days do not show as a rule any marked 

 progress over twenty years ago in reducing this work to an 

 exact science; that is, no progress similar to that which one 

 may find in connection with dry kilns. 



In the dry kiln we have registering instruments that 

 shovir the temperature and moisture conditions, and have 

 reduced the matter to a point where a man can now posi- 

 tively know what to do, and may know what he is doing 

 at every hour in the process of treatment. 



On the other hand, in the conditioning of veneer blocks 

 there is practically the same thing in vats, the same thing 

 in steaming boxes and the same haphazard practice fol- 

 lowed, which is dependent more upon the native skill and 

 the instinctive judgment of the man in charge than upon 

 any scientific basis or positive rules for guiding. There 

 may be some who keep thermometers in their boiling vats 

 and steaming boxes and a record of these things, but the 

 writer has not encountered them in the rounds. Talks 

 with machine operators bring differences in expression of 

 opinion about the treatment to give this wood and that 

 wood. It shows also that during the summer season 



