View Full Version : Sitka Spruce

05-22-2002, 06:40 PM
Whats with this gorgeous wood?
Ya rip a streight board and it bows, joint it streight and rip the other edge and it bows the other way. Is this the norm? The stuff is dry, clear and edge grain old growth.

Bruce Taylor
05-22-2002, 06:47 PM
Case-hardened, perhaps...or else (less likely) you've got some "tension" wood in your lot. Sitka can have a lot of twist in the grain, and that can come unscrewed on you -- but if this is old growth, as you say, that's probably not your problem. Finally, if there's been a recent change in local humidity your wood might not have adjusted to the new r.h.

I'd put my money on the last. If your boards are warping toward the new cut, you've probably had a recent rise in humidity.

[ 05-22-2002, 07:55 PM: Message edited by: Bruce Taylor ]

Memphis Mike
05-22-2002, 06:52 PM
Lay the convex side on the grass, in the sun
in your yard. Wet the concave side with a towel
moistened with water and sit in the "moanin chair"
and watch it straighten out.

Its kinda like rollin over a half dead lamb
and then watchin him walk again. :D

[ 05-22-2002, 07:57 PM: Message edited by: Memphis Mike ]

Wood Guy
05-23-2002, 07:53 PM
More likely than not, the pieces you have contain "tension" (or "compression" ) wood. This is evidenced by an abrupt change in grain density across the face of the board, sometimes in localized patches, combined with a darkening (usually to yellow/brown) of the color and wavyness of the grain on the vertical grain face. The wood in these areas also appears "brashy" or somewhat "dead". If it does, do not use it for any structural application. This defect has a tremendous affect on the strength of the piece and will seriously compromise the integrity. (especially in a spar.) Unfortunately, there is no remedy for this situation but to select alternate boards.

As to case hardening; While somewhat unlikely, (due to the advances in kiln drying technology), the situation will correct itself over time. If you don't have the luxury of time to wait, remedial measures involve steaming the wood for a period of time to "stress releive" it. (Steaming at 170 degrees for 1/2 to 1 hour is the recommended rate)

Either way, the best solution is prevention. That is to say, purchase your wood from a reputable supplier who understands the manufacturing and grading requirements for boat lumber. Also, ensure that all product is inspected and certified to "mast and spar" grade.

05-24-2002, 09:19 AM
I have already cut a new peice. It's grain was very wavy and stripey, I had laminated it hoping that would help but it didn't. Regretably due to the waves and color variation it was also very pretty and I am replacing it reluctently.

Nick Kent
05-25-2002, 01:07 AM
Sitka is some of the hardest stuff to work with and that is all there is to it.

Hugh Paterson
05-28-2002, 07:51 PM
Mike, Half dead lambs, Moaning chair, twisted and warped timber, christ and I thought I worked in a strange place :D You lead an exciting life fella ;)