Working with a slightly cupped board - Woodworking Talk - Woodworkers Forum
 
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post #1 of 6 Old 02-25-2013, 11:47 PM Thread Starter
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Working with a slightly cupped board

Hi All -

Please excuse any naivete in this post, I am somewhat new to woodworking (maybe 1.5 years exp).

I am building a media cabinet for a friend. This is the first time I have used hardwood (using Alder). I glued up all of my panels, and then took them to a local shop to be trimmed, planed and sanded. I got the boards back today, and one of them, the side panel of the media cabinet (which is 3/4 inch) has very slight cupping - perhaps 1/8th of an inch, certainly less than 1/4 inch. I have attached pictures of both the design built in Sketchup, and the panel that has cupped. I will join the panel to the top and bottom using a kreg jig and 1 1/4 inch screws. A few questions:

  • Is there any reliable way to fix the cupping? Keep in mind the panel is now perfectly cut to size, so I would rather not cut it in to pieces and re-glue it, as I am certain to come out slightly smaller than its twin on the other side.
  • Can I simply clamp the piece flat, and use the kreg jig to connect it on either end, and then unclamp it? The wood is malleable enough that when I press it against a flat service, the cupping flattens out.
  • The bottom of the cabinet is 3/4" birch ply, and has slightly warped as well. Can I still use it, and rely on the weight of the cabinet (should be quite heavy) to flatten it out?
All other pieces are perfect. Hoping to assemble this weekend and would appreciate the expertise of my fellow wood workers to stay on schedule.



Thanks in advance - long time reader here, but am relatively new to posting.



Randy
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post #2 of 6 Old 02-25-2013, 11:51 PM
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Fool proof way? No, is the piece going to attach to something perpendicular that you can use to draw it flat with the screws?

The tools don't make the craftsman....
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post #3 of 6 Old 02-25-2013, 11:55 PM Thread Starter
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Hi Ryan - Thanks for the quick reply. The answer is yes - the side panel will connect perpendicularly to both the plywood bottom, and the hardwood top.
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post #4 of 6 Old 02-26-2013, 05:04 AM
where's my table saw?
 
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no need to cut all the way through

just get a thin kerf blade, or like from the hand held battery powered saws, about 1/16" wide, and make a few kerfs up from the bottom to within 3/16" or 1/8" of the top.
Then flatten it out and force some thin wedge shaped strips, they could also be straight, into the kerfs to hold it open. Don't drive them in as that may split the wood on the "good" side. You can plane them down by hand until almost flush, then sand the rest down flush after the glue is dry.
Other attempts at flattening MAY work, but this definitely will. I can't tell from the photos but it looks like you may have oriented all the wood cupped side up...I donno? The wood should be alternated cup up, cup down, for the most stable glue ups.

I had the same issue here, but I sawed all the way through and reglued. This did reduce the size by 1/8" or so, but it didn't matter in this case:
http://www.woodworkingtalk.com/f2/bi...t-buddy-48967/

The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)

Last edited by woodnthings; 02-26-2013 at 05:06 AM.
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post #5 of 6 Old 02-27-2013, 04:51 PM Thread Starter
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Thanks so much for the tip - I tried this and it worked beautifully. I am all about splines now - you saved me tons of additional work and money. Thank you again!
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post #6 of 6 Old 02-27-2013, 08:30 PM
where's my table saw?
 
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did you take any photos?

Quote:
Originally Posted by RFEndemann View Post
Thanks so much for the tip - I tried this and it worked beautifully. I am all about splines now - you saved me tons of additional work and money. Thank you again!
Glad it worked out for you as well as you said. Some before and after photos are always good when a tip is recommended so others can see the results!
Did you use straight or wedged shaped splines? It's pretty hard to get those that thin and wedged shaped at the same time, but all you need to do is set the blade over at a 1 or 2 degree bevel and make a pass then flip the board over and make the next pass OR cut it at 90 degrees for 1/2 of the angle.

The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
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