After a 7 month wait for my molder, I should be able to get it in the next week or so....Before I start wrecking a bunch of expensive Red cedar, I though I might experiment with a couple of lifts of high grade hemlock from the local big mill. It is kiln dried as far as construction lumber goes....If I make a bunch of v groove paneling out of this wood, will it shrink excessivly installed indoors? In my neck of the woods, I have never been able to air dry anything lower than 12% outdoors(to give an idea of local climate).
First, you need a moisture meter to KNOW the MC of the wood your working with. If the wood will be installed outside in outdoor humidity conditions, 12% is good. If It's going to be installed indoors in climate controlled conditions, that's another story.
If you want to be safe, get the wood down to 6-8%. One thing I don't know is if you mold your wood at 12%, then bring it in to acclimate it, will it shrink uniformly. If you had clear material, maybe. If you want to be sure, get it to 6-8% first. Maybe someone with more experience can chime in here.
But in any case, you need to have the wood at 6-8% before it's installed. Otherwise you will get gaps.
I have seen lots of mills drying hemlock, but I have never seen one drying to the lower MCs because the woodgetsvery brittle and machining defects, especially chipout, abound. Can you find some aspen or maybe some basswood?
I don't have any experience with hemlock going through my moulder, but ironically spent the weekend running a rush order of cabin siding, had to use store bought SYP to get it done. Never had as many issues as using this stuff. I need to put the meter on it to check the MC but it is dry, probably too dry, and I suspect it may be case hardened, so I would be careful about buying too much until you see how it runs.
Indeed, virtually all construction lumber has drying stress (or casehardening). SYP is perhaps the worst. High temperature drying is common and makes machining difficult as well. Did the ink stamp have HT on it, indicating Drying was hot enough to kill insects. http://spartanburgforestproducts.com/our-products/southern-pine/southern-pine-grade-quality-marks/ (http://spartanburgforestproducts.com/our-products/southern-pine/southern-pine-grade-quality-marks/)
Hemlock is hard on cutter knives those knots are a bear.
Thanks for the input everyone. The reason I was gonna use hemlock is because it is readily available here and the high zoot grade is realativly cheap. A consideration when a greenhorn such as myself starts molding/planing. There is pine available in select grades but have to be shipped here and is pretty nice stuff to be wrecking right off. Regardless, the molder seems to be delayed again....
arg-smiley
Percy do you have cotton wood. It makes nice moulding. My local cabinet guy says he can make it look like oak or maple with thre right stain. It takes paint and stains very well. Machines cery nice. One could experiment with some.
Quote from: rjwoelk on October 30, 2018, 10:32:27 AM
Percy do you have cotton wood. It makes nice moulding. My local cabinet guy says he can make it look like oak or maple with thre right stain. It takes paint and stains very well. Machines cery nice. One could experiment with some.
Yes!! I have cottonwood. Thats a great idea. Takes a long time to dry but that could be an interesting project for the molder...thanks
I cut up a chunk of cottonwood, was looking for something for drawer sides, and found that when I plane it, it smells like that cheap plywood made in China. Figured out what they were making the ply from.
Just to clarify , rather than referring to high temp kilns, HT on a gradestamp means heat treated to 133*F for 30 minutes at the core, this is easily done in a conventional kiln running at 160 or 180.
The letters HT (heat treated) on a southern pine grade stamp mean it was dried at a temperature that kills insects and eggs. See http://spartanburgforestproducts.com/our-products/southern-pine/southern-pine-grade-quality-marks/ (http://spartanburgforestproducts.com/our-products/southern-pine/southern-pine-grade-quality-marks/)