How to fix warped wood?

[SkinnyPirate]

I've had a blank of alder that was laying around in my basement and over time it has cupped, since it's really thick(about 1.5 inches), is there any way to fix the wood? I've tried steaming the wood with an iron and clamping it tight between two flat surfaces but I'm not sure it'll work...If it doesn't, is there any other alternative or am I really going to have to buy another blank?

 

[Bruce Johnson]

There's no point in trying to bend it back to flat; it will just spring back to the cupped shape. The solution is to machine it flat. Use a planer or a router fixture with a wide bridge base to cut it flat. If it's too thin to use for the body you are planning, glue a top on it.

 

[SkinnyPirate]

Yeah it's a solution i'd like to avoid if possible, the body is already fairly thin and I do have a top to glue on it anyways but it's really thin too so I don't want to remove too much material. Do you have any idea of the thickness it removes depending on the curve?

 

[charlie monroe]

Lay the board flat and measure it's height from whatever surface it's laying on. Subtract the initial 1.5".

You will probably lose double the remaining dimension. Perhaps more, but I can't see the board.

 

[Manton Customs]

Lay a straight edge across the cup and measure the gap at it's deepest, though remember the cup will be on both sides, so you'll lose double that measurement (as mentioned above). Unless it's a guitar with a Floyd Rose/Trem or you are trying to exactly copy something it won't matter having the body a few mm thinner. I make all my bodies 1.5" thick anyway unless I'm doing either of the above, so you should have enough material even with a thin top. Unless we are talking an extreme cup, in which case just buy a new blank.

I have flattened cupped bodies by clamping and moisture with limited success, but it is a big headache and there is always a very good chance it'll just cup again. These were in cases where too much work had already been done to stop, so I needed to save them. In your case I'd either plane it or just buy a new blank. It may sound extreme but if that cup comes back halfway through work or during finishing it will ruin your day/week!

 

[Danomo]

Made me think of this:

 

[SkinnyPirate]

I'll post a photo of the wood later, but I thought about something, if I chamber the body, would it make it easier to straighten with clamps and moisture?

 

[Bruce Johnson]

Nope. Chambering it might make it easier to push it flat with clamps, but it will still spring back. You would be wasting your effort trying to straight it with heat and moisture.

 

[SkinnyPirate]

Damn, I thought it might relieve some of the stress of the blank, so my only hope is the plane it again and hope it'll be thick enough to use?

 

[FBB Custom]

I would plane it. If it is too thin when you're done you could add a back or an accent laminate between the top and the alder.

 

[SkinnyPirate]

Adding a back would be a very good idea! I already plan on adding a black veneer between the alder and the top, but it won't add much thickness though. Anyway, thanks for the help everyone!

 

[sissy kathy]

There are several ways to 'fix' this problem, most of which you won't want to hear. First is to cut it into strips and rotate every other piece. that will even out the cup, but you'll lose width, but instead of having one large cup you'll have many small ones that are easily planed out.

Another method is to cut kerfs into the blank almost all the way through and then glue shims into the kerfs, this has the advantage of keeping the side not kerfed intact and making the piece appear to be one piece. This is a tedious process though as the depth of your kerfs have to be readjusted for each pass.

If you really want to salvage this piece with minimal effort consider making the cupped side the rear of you instrument, and sculpting the edges, it'll still be cupped but the effect will be minimized.

 

[hdracer]

You could make a NS type body with it.