The Forestry Forum
General Forestry => Drying and Processing => Topic started by: forrestM on July 28, 2021, 05:35:07 PM
I have a load of 7/4 and 8/4 poplar I will be using for framing material in my nyle l200 m. I am in Virginia and figured 11% would be the lowest I would want to go with framing material. What do you guys typically dry yours to?
Just to put it out there - I am running it as group 2 with db 120 and wb at 90 since it is already at 16-20 percent moisture. Planing to sterilize at 140 for 48 hours as well.
Thanks!
Store bought is 19%, we've run in the 12-15% range if it fits in the kiln. Got some 20-26' material air drying, hoping it'll be down around 15 by the time we get to it. Borate the lumber, ppb's love poplar. We hit it green from the saw and I'll spray the frame down again when that stage is complete.
If it is 20% moisture and if I was drying it further, I would set the DB at 120 and the WB at 75 and let er rip.
As WDH said you can change your settings. For building materials the moisture content varies across the country generally between 12-19%. It will complete drying once built but most of the shrinkage has already occurred. The important thing is to be below 20% to prevent mold.
Free water is considered to be gone at 20% MC, and with it susceptibility to a range of pests, and (under our rules at least) a piece can also be visually stress graded. And that's about when you want to use it in your house.
You don't want dry framing, dry framing leads to weak buildings. Lumber shrinkage as it dries in place allows it to get a good grip on the nails and/or other fixings and fastenings. Houses built out of wood dry below EMC for the location) that then has to swell to come up to the environmental conditions actually loosen the friction holding the wood to the fixings and fasteners. And then they blow over in the first hurricane.
I live in the most active hurricane zone on this planet (and probably the surrounding ones as well :D). I know these things to be true.
This is the table of adjustment factors for connections used at various moisture contents. Notice that a common nail when driven into green wood that subsequently dries loses 75% of its allowable withdrawal capacity and about a third of its shear capacity.
(https://forestryforum.com/gallery/albums/userpics/10017/connectionMCadj_001.jpg?easyrotate_cache=1627731689)