Dry Kilning of Fir Commons Being Tried

A series of experiments have been started at the plant of the Wheeler, Osgood Company in Tacoma, Wash., on kibodryiug common ffr lumber.

The tests are in charge of Albert llerman of the United. States Forest Produets Laboratory at Madison, 'Wisconsin, assisted by a committee of lumber manufacturers of Oregon and Washington.

This, of course, is one of the most impoltant moves ever und.ertaken by the Qouglas fir industry, and. is fathered by the 'West Coast Lrumbermen's Association. It is the hope that the experiments will demonstrate a method of running common lumber through the dry kilns that will keep the knots from falling out. Particular attention is direeted to l-inch and 2-inch stock.

If this is acconplished it will mark the arrival of a new tlay in the Douglas fir industry. Under established methods, common fir lumber is surfaeed green, from the saws. It then is pilecl in the open air to dry. By the time it is ready to ship it naturally is discolored., and sometimes dirty. 'While it loses none of its strength and is just as valuable for praefically all uses in which common lumber generally is employed, it nevertheless is unattraetive in appearance and is at a sad advantage in those markets where it comes in eompetition with bright, clean-looking lumber that is surfaeed. 'after it is dried.

fn some cases it is shipped green from the saw ancl left to dry in the retailer's yard., or on the job where it finally is used..

The principal trouble heretofore encountered. in drying fir commons and. then running them through the surfa-cing machines has been the tend.ency tif the knots to drop out oi to pull out. As the wood ffbers around. the knots eontract. in drying, the knots of eourse become loose. If they don't drop out in hanclling they often are pulled out in planing.

Now it is this condition of unequal shrinkage between the knot and the wood. ffber that thi government experts are f,rying to overeome. If they sueceid in preventing a degrade of. more than eight or ten per cent in the kiln-drying plgcels it is geneially understood that their experiment"s will be considered successful. The "fall downJ', or d.egrades in air drying run from four to eight per cent.

_Kiln-drying colnmon lumber offers a great many economie ^adv_a-ntages to the ffr folks. 'While it woultt requiie a considbrable initial investment in kilns, it would-preclude the neeessity.-of_having an immense amount of capifal tied up in lumber piled out in the yard. Some of the larger mills in-the Northwest have as high as 75,000,000 feet in pile at one time.

- Kiln-drying also would reduce to a minimum the ground. for eomplaint agains-t the_ur,rdue shrinkage and the ine[uality in size of eommon fir. It is a well-estJtrtistred fact ttat ff"r lumber d.oes not all shrink alike and this often learts to difrieulty when lumber of varying sizes gets onto the same construetion job.

T-he Long-Bell Irumber Company, which expeets to start ils { operations within the coming year, have plans to kilndry -thgir commons as well as theii irppirs regairdless of the results of the_ gxperiments now urdei way.