hello,
Just about to finish my chamber and fire up my new-to-me Nyle l200m! I have an order for poplar shiplap siding that I was thinking I could dry down to 15 percent in the kiln as a test run. It seems like it would be a gentle and hopefully not too difficult break in. It will be 2000 board feet of yellow poplar. 3/4"x6". I'm cutting it at 13/16 of an inch to allow for a shrinkage to 3/4" target thickness. Planning to cut and stack directly in the kiln.
I ordered some of the 1/2 inch probe screws from Nyle. Will they work in this thin lumber?
What kind of schedule would anyone recommend/ how would you approach this? Or any tips, in general?
I would normally air dry siding material, but It is winter and I have a kiln now...and the customer wants it sooner than later.
Thanks,
Forrest
I would dry yellow poplar fast like pine.
You can dry poplar fast, but in order to not sticker stain the poplar, there should be at least a 10° DB/WB depression, preferably 15 or 20. That will be hard to do with green off the mill poplar. If you raise the temps high initially there will be more moisture driven off than the kiln can handle, so I'd put it in and set the depression accordingly.
I would set the DB at 120 and WB at 75 and let her rip. The key is to not to overload the kiln with wood so that the dehumidification unit can remove the water that you are evaporating at a rate that does not create the ultra humid conditions that lead to sticker stain. Nyle has a chart that tells you the maximum load that you can put into the kiln given the species and the initial moisture content. I believe that yellow poplar is in Wood Group 1 which calls for more aggressive drying.
The compressor should be running at 100% which is what setting the DB at 120 and the WB at 75 will cause to happen. Your compressor will come on and run when the DB get to 80 degrees and the WB gets to 77 degrees. For the first day or two, the heat required to evaporate the water will keep the temps on the low side, and as the wood gets drier, the temps will begin to climb. Keeping the big depression between the DB and the WB will insure that the compressor runs flat out.
Poplar dries very fast but if it is too wet you might want to limit your load size to 1500 bf or 2 loads of 1000 bf if you need 2000 bf total. If the load size is smaller it will also dry faster but this is only true for softwoods. Hardwoods dry at the speed that the wood will allow.
On these types of wood load how many gallons are you pulling out per day? I can only imagine it's coming out pretty fast?
Quote from: K-Guy on February 16, 2021, 09:20:05 AM
Poplar dries very fast but if it is too wet you might want to limit your load size to 1500 bf or 2 loads of 1000 bf if you need 2000 bf total. If the load size is smaller it will also dry faster but this is only true for softwoods. Hardwoods dry at the speed that the wood will allow.
^^^ this.
You will have less likelihood of staining if you split the load, because it will dry closer to the maximum daily targeted rate.
Be sure to use dry stickers. For a 13/16" thick board, I would sticker on 12" centers in order to help keep the boards flat.
This is more of a question than an answer. If the wood will tolerate the moisture loss what would happen if you opened the vents? I know in the mill in a conventional dryer the vents are wide open during part of the cycle.
You can vent but that means heat loss, so it may not gain you anything in efficiency if the heat has to come on.