I’m building a garden gate of redwood 2×4 z-frame and 1×6 redwood ridge & valley planks.
I selected nice straight 2×4 lumber for top & bottom rails and the z-brace, then allowed them to dry for two weeks. The 6-foot z-brace piece has warped a bit and also bowed about 3/8″. Of course the bowing will cause the the gate to warp and not close right.
I bought another piece today with a tighter grain in hopes that it will shrink less and so stay straight.
The attached pics show that both end grains are similar on both original and replacement boards, and both have pretty straight grain along the length as well. I thought that with grain similar on both ends, a board would shrink uniformly and so not warp or bow.
How can one tell if a piece of lumber is likely to remain straight as it dries?
Original Board
New Board
Replies
Spend the kid's college fund on vertical grain redwood.
That new board is mostly sap wood ( cream color) it may not twist, but will rot.
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See if you can locate a couple of pieces with vertical grain. The growth rings on the endgrain would appear as parallel, nearly straight, vertical lines, like a comb.
How large is the gate? Assembling the gate sooner, rather than waiting a couple of weeks after buying the lumber may actually help keep everything straight as the lumber dries.
What Sphere said.
Those growth rings are a mile wide.
It's probably a 20 year old tree, fertilized and watered = cheesy weak wood.
There is something to be said for a tough, 300 year old Redwood (or Cedar, or Fir). Unfortunately, they are harder to find......
Scott.
Edited 9/29/2009 1:24 am by Scott
Unless you can get dry, quarter-sawn, straight-grain stuff, it's just a guess.
What you have is at least better than pieces that have the heart in middle of the board.
Letting it dry awhile is a good idea--most of the redwood I can get is sawn green, and is so wet that you can actually feel water mist shooting in your face as you rip it. You can feel by its weight that it's still really wet.
Letting it dry in your shop for a week or two should tell the story. Or, try picking thru the pile at the lumber store, or go to another store to check out their supply. On a recent project (an outdoor dining set), I bought almost all my 2 x 6's from Lowe's, but HD happened to to have one 10' 4 x 4 that was absolutely flawless and perfectly dry--quarter-sawn to boot.
All wood warps and twists and bows as its moisture content changes. You need a design that allows for that without self-destructing. You need joinery that can accomodate the expansion and contraction cycles.
How flat do you think it needs to be?
I built a gate of the type you are describing. It was built from kiln dried, clear pine. IIRC, a five foot wide X five foot tall gate cost about $125 for the materials. It has remained flat and beautiful for several years now. It is about time to renew the oil finish that's on it (Penofin oil), as the rainy winter season is coming.
The extra cost of the material was more than compensated for by the ease of construction and installation as well as the 100% perfect appearance and functionality since it was installed.
Think about it.
Edited 9/29/2009 2:47 pm ET by Mike_Mills