I know it's a little late to ask now but I wonder if I've been doing it right all these years. For the past 15+ years I've been laminating my own panels(blanks), I have always alternated the grain when edge gluing "quarter sawn" lumber redwood and cedar: Looking at the end grain it would look something like this \\\\\\//////\\\\\\//////\\\\\\////// We've made hundreds of sandblasted signs and never had a problem with warpage. On one particular job, we were pressed for time and ordered 2 prelaminated blanks. I wont name the supplier but they warped, one of them badly. They had been laminated something like this: \\\\\\ \\\\\\ \\\\\\ ////// \\\\\\ \\\\\\. I talked with a rep from the blank company and he said that they didn't laminate their own blanks but he did say that some sign builders prefered their blanks (that had quarter sawn lumber) to Have all the grain running in the same direction\\\\\\\\\\\\\\\\\\\\\\\ because, he said, they could turn the sign so that water wouldn't collect in the blasted grain. It would be better if you could always get perfect 90 degree vertcal grain lumber. Anyway, my question is; have I been doing this wrong? Which way do you prefer? Thanks
------------------ Wayne Webb Webb Sign Studio,Inc. Blastin' "woodesigns" in Chipley, FL "autograph your work with excellence" webbsignstudio@digitalexp.com
Posted by Si Allen (Member # 420) on :
Norm Abrams, Master Carpenter on "This Old House" and "New Yankee Workshop" ALWAYS alternater the grain to prevent warpage, when laminating ANY wood! 'nuff said!
------------------ Si Allen #562 La Mirada, CA. USA (714) 521-4810 ICQ # 330407 "SignPainters do It with Longer Strokes!"
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Posted by Steve Purcell (Member # 1140) on :
Wayne,
Your method sure sounds right to me.
Most lumber these days is slash sawn and the amount of true quarter sawn that results is minimal.
I always reverse the grain, and the narrower the boards, the better.
------------------ SCP spurcell99@mediaone.net Cape Cod, MA
Posted by Michael Boone (Member # 308) on :
I like the way the other guy did it...and I agree with his thinking.To compensate for warping...I make my blanks using two thicknesses of material.This is a little more work but the resulting sign is strong ,stable and satisfies me and the customer...can't beat that,right? Perfect 90 degree vertical grain?Sounds nice...but trees are living,imperfect creations....look out now..what's next?...computer generated lumber ...perfect to the point of being sterile...who's gonna write that software?? I bet Mark Fair can come up with some hardware to output this product...somethin like the Gerber Wood Bea?
You definatly have the right idea. If you looked at the end grain and chose where the heart of the tree would be, then alternate the up downs of that heart. I've been finding less warp by gluing up slabs from 2x6's rather than 2x12's too. Not seeing any warp in the 4x materials. Also, sometimes when we get a bit of a warp, we turn the sign around and allow it to warp back.
------------------ The SignShop Mendocino, California "Where the Redwoods meet the Surf"
Posted by Dave Sherby (Member # 698) on :
Alternating is the right way to do it. You will only find an occasional piece that has truly straight verticle grain. When that glued up slab wants to warp, IT WILL WARP and no mount of hardware will stop it.
I too seldom use wider than 6 inch boards.
I don't fasten redwood down tight. I try to use fasteners with slots instead of holes so when the sign expands and contracts, the fastener head will ride in the slot. As stable as redwood is, it still expands and contracts from moisture. I saw literature that said redwood will expand & contract from 1 to 3%. 1% of a 4 x 8 panel is almost a half inch!
One last tip to minimize warping. When you sandblast a sign, you are changing the surface tension of the wood. This has a tendancy to promote warping to begin with. Now if you change the rate of moisture movement thru the wood, you can increase that tendancy. Therefore, what ever I use on the majority of the front of the sign, I use on the back. Stain on the front - same stain on the back. Paint the front? Paint the back! Paint and stain will have different rates which water vapor will pass through.
------------------ Dave Sherby "Sandman" SherWood Sign & Graphic Design Crystal Falls, MI 49920 906-875-6201 ICQ: 21604027 sherwood@up.net
