I have a slab of European copper beech 9' long x 38" wide x 4" thick. It's been air drying here in CT for approximately 15 months. MC is 20% with a mini Ligna, temp about 45F. (I did reading after full day inside, temp. at 52F.) I have planed and sanded surface to show a prospective client who'll be looking at it on Monday. It is very figured, with some spalting at edges, some small cracks, etc. She may want it for a dining room table.
Do I need to dry it below 10% for it to be usable? I wouldn't mind it moving a little - I don't want it smooth like a conference table. At 4" thick and secured with angle iron across width, do you think it will cup, warp, etc.? Even if it's finished all sides? What would you recommend for a finish? I did an air dried table with Danish oil, but it was for my conference table and doesn't get a lot of use or abuse. What would you recommend to keep slab from cupping if it's only resting on, say, stone legs (no apron)?
(Sawing and Drying Forum)
From contributor R:
Using that steel will actually cause it to bow and split. The wood will shrink when put in the house, the steel will only add a little strength to one side. The top will shrink, the bottom will less, the top will become concave. At 15 months it just has a good start at drying. For air drying, that slab should sit at least 4 years, maybe more. The meter you are using is not measuring the moisture in the center of 4 inches. It probably only measures 1" deep. It will move as it wants to - nothing will keep it flat, nothing! I would use a polyurethane for the finish, about 3 years from now.