Drying Massive Slabs

Air-drying and kiln-drying 12/4 or 16/4 hardwood slabs is slow and difficult, and the results can be mediocre. February 29, 2012

I have some oak and pecan trees that range in diameter from 35" to 45" that will have to be cut down. Can mills with kilns be trusted to dry 16/4 and 12/4 slabs or is air drying safer? I am thinking of selling the wood myself.

Forum Responses
(Sawing and Drying Forum)
From Professor Gene Wengert, forum technical advisor:
Oak thicker than 8/4 is really hard to dry by any means other than vacuum. In a kiln, 8/4 would take 100 days and 16/4 about a year unless air dried first. Quality will be poor even with air drying. Pecan is not quite as bad, but it is tough too. All in all, cut it thinner and then glue it into big pieces.

From contributor B:
Sure, some mills can be trusted, but not many. The problem is it ties up their kilns for so long. Contact the local kiln you are considering for your drying services and ask them how long they expect it to take and if they have ever dried that particular species and thickness before. Then get a price from them, and compare that to what you expect to sell the lumber for. Also ask them if they can give you some type of guarantee if they ruin your slabs. I saw and dry lots of pecan flitches, mostly 12/4. The only way I can keep them flat is with parallel clamps made from channel iron. I typically air dry under a shed with limited air flow for 4-8 months and then kiln dry for 4 months. I have 16/4 live oak slabs that are 50 inches wide that have been in a kiln for 11 months and they are at 13%.