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I have several boards of 8/4 oak that is 12-16" wide that have a severe cup. It is probable 3/4-1". Is there a way to fix this? Is my best option to rip it down the center of the cup and then surface the wood.
I bought the wood several years ago and it has been in my shop. It originally had a little cupping to it but it has gotten worse. I did have it stacked in my shop, and yes it was stickered. I never did rotate it. Was that a contributing factor?
Any ideas would be helpful.
Thanks:confused:
If it was stored with 'air on one side' I would flip it over for a while. If it was stored with air on both sides I would remove some wood from convex side ,that might make it actually move toward flat.
Not much choice but to rip it.
Rip it, I would rip the rift sections off and rip the center up into quarter sawn material (the sides will be quarter sawn orientation) and use it for parts. After it is ripped up, give it a few days to dry the now exposed interior before jointing any faces.
With a severe cup, the only practical way to retain the majority of the thickness is (sadly) to rip it...but if you keep track of the boards carefully, you may be able to re-assemble it with minimal indication that it was cut and glued back up.
Put it aside for a project that requires narrow rips.
I definitely have less experience than the Guys above, but I would be very curious to see close up end shot photos of the boards showing end cut ring pattern, ideally w a straight edge applied.
I would think if in fact stickered w airflow relatively equal on all sides, and they came out this cupped,these are all plainsawn full tree width? Marc
If the board is fully cured I don't believe there is hope of straightening it out with more stacking. Even if it straightens it would likely return to a cupped condition in short order. Ripping at least once is likely the best recourse. Rip into slices, face joint each piece until it lays flat then edge joint and glue back together.
If it's dry 6-8% there isn't much you can do except to rip it into 1-2" strips, joint their edges, and then glue the strips back together to form a flatter board. Then plane it flat and use it, or find a use for small pieces of it, cut the pieces oversize and plane them flat, then trim them to final size. The result will be usable, but much thinner than the original thickness.
I once took some 2 X 10 construction grade SPF flat sawn lumber and kind of made quarter sawn out of it by ripping it in 1 1/2 square strips, rotating each piece 90 deg, then jointing each piece, discarding the piece with the pith in it, and then gluing it back together and planning it flat. The result was some interesting grain and much more stable wood that looked much like quarter sawn.. Labor wise, it wasn't worth doing, but the result was kind of interesting. If you really want to save this wood and you are doing it for yourself, you might want to try doing this. If it's for a job, it's cheaper to buy new flat wood. It's a lot of work and the result considerably smaller than you started with.
Charley
There is no reason to rip it into such narrow strips. And certainly no reason to reassemble a bunch of narrow strips into wide boards unless a special project calls for it. Only rip it enough to plane the cupping out.Quote:
Originally Posted by Charles Lent
cupping across the width or in the length or both? Either way what you need it to be thickness wise is what matters. if its 8/4 and you need a final of 1 3/4 depending on your lengths then you may be S out of luck. Cross cut to your shortest lengths and rips first as usual then you are working with less bend overall. you can keep the internet gurus. ill go with Mel every time clearly he has machined a lot of material and understands it. I also think stickering to try and force things flat or keep them flat is something i would never try and do, you should want to get the tension out of the wood not try and force it to behave a certain way trying to make it what you want.
Andy, don't you mean joint it rather than plane it? The rollers on the planer will compress the cup while in the planer but once it's out the cup will return. I would joint it first with the cup side down, then once I had a flat face run it through the planer.Quote:
Originally Posted by andy bessette
Doug,Quote:
Originally Posted by Doug Landphair
I think Andy was referencing hand planing but I could be wrong.
Regards- Bill
I might have said "flatten it." :)
If, as the original poster says, the width of the board is 12 inches and the cup is 3/4 to 1 inch on 8/4 material, then you will cut away about half the thickness getting it flat and consistent thickness. If he needs anything like 8/4 material, he has no recourse but to rip, surface, plane and re-glue.