Jump to content

Reshaping warped boards


Recommended Posts

I got some lovely Bosnian quilted maple a little while ago but one of the sets started to twist and cup as soon as I took it out of the box, in fact it went ping when I cut the tape holding it together for shipping so either the wood wasn't dry or it was the change of climate, though my meter read it as 11-12%.

In the past, I've had success with applying heat to a cupped board to straighten it out but these are a bit thicker.  So After a bit of research I came to the conclusion that cupping happens because the concave side has dried more quickly than the convex side and one way to fix it is to apply some water to the concave side then clamp flat. So that is what I did...

First off, I clamped the boards flat together (so that I could see they were actually flat) gradually applying pressure over an hour or so until they were completely flat.

Then today (couple of weeks later) I loosened the claps and the boards remained flat but I only had the clamps off for a few minutes. Then I cut up some spare pine door stop to use as stickers and put it back in claps (lightly clamped this time).

So questions...

1. Anyone else done this? Does it work, or will the boards just spring back to how they were with clamps off after a while? 
2. Should I leave it like this until I'm ready to use the top or should I take the clamps off after a while then store them and see if they move again? 

I know stick these to a mahogany body will probably hold it and carving it will likely get rid of a lot of the tension but this top is for a semi with an f-hole so really need to carve prior to sticking to the body which would leave a bit of time for movement. 

Cheers
Ash

Jri8bEwKxBDTldMCxJxWamM2btRO_aStX4JzBQ_Q

 

 

Link to comment
Share on other sites

no idea... but I'm hear for support! 

my experience with wood is there can only be a ltd win in terms of fighting it.  you could try to plane off some wood on the wet side to hopefully get it to release some moisture.  adding water to wood seems dangerous as you don't know what way it's going to go and it could get worse.  Ultimately, I think with something like this you just have to give it time, see where it ends up, and then shape it.  I'm sure there are folks with more experience on this topic as my approach has always been to not fight it... so I'll let the fighters advise.

Link to comment
Share on other sites

1 hour ago, mistermikev said:

no idea... but I'm hear for support! 

my experience with wood is there can only be a ltd win in terms of fighting it.  you could try to plane off some wood on the wet side to hopefully get it to release some moisture.  adding water to wood seems dangerous as you don't know what way it's going to go and it could get worse.  Ultimately, I think with something like this you just have to give it time, see where it ends up, and then shape it.  I'm sure there are folks with more experience on this topic as my approach has always been to not fight it... so I'll let the fighters advise.

Yeah the trouble is it's twisted and cupped, and the concave face is the bookmatch face so I need to be careful about taking material off. It's also not much thicker than I like to use for carving tops so I want to avoid taking material off at all if I can. I think I'm just going to leave it stickered under pressure for a few more weeks and see what happens. Worst case scenario, I imagine it will end up being a more shallow carve with binding.

Not a good start to my first dance with quilt!

  • Like 1
Link to comment
Share on other sites

Since it cupped to the hidden side it seems like it got moisture on the outside, i.e. it must have been drier when it left Bosnia and the outsides got their share of fresh English mist.

As Mike said, adding water seems dangerous.

I'd say store it as wood should be stored while drying. That means having them on a flat well ventilated surface with a slat between every surface and some weight on the uppermost board to keep them from warping. Of course you can continue using the clamps but I figure you might find other uses for them. A couple of stones should do the trick.

Edited by Bizman62
Link to comment
Share on other sites

39 minutes ago, Bizman62 said:

Since it cupped to the hidden side it seems like it got moisture on the outside, i.e. it must have been drier when it left Bosnia and the outsides got their share of fresh English mist.

As Mike said, adding water seems dangerous.

I'd say store it as wood should be stored while drying. That means having them on a flat well ventilated surface with a slat between every surface and some weight on the uppermost board to keep them from warping. Of course you can continue using the clamps but I figure you might find other uses for them. A couple of stones should do the trick.

This is how it cupped, which makes me think it wasn't dry to begin with. I also think it was bookmatched only just prior to being sent as apposed to bookmatched and stored a while.

Screen Shot 2019-06-06 at 17.31.11.png

Link to comment
Share on other sites

Oh, that changes the situation. Again a simple picture described the issue better than a thousand words in Klingon.

Letting the pieces acclimate between slats and under some weight still is seems to me like a valid option. If they stay level under a board even without any extra weight they should behave nicely on the guitar as well. However, as you're going to build a semi-hollow, finishing both sides of the top in the hollow parts might add to the stability.

Link to comment
Share on other sites

Every single piece of highly quilted maple I've had came to me flat and dry and cupped like a bastard immediately after resawing. Actually immediately after coming out of the clamps as I've learned to clamp be fore it gets a chance to bend much. I've tried what you are doing and got very little show for it. A buddy of mine here on the forum @pauliemc, once told me he tried that as well and got a broken board for his troubles. My solution is to just sand it flat after it's meed glued up.I'm going to lose a bit of the book match in the carving I do anyway. And Happily, I've discovered that some of the best quilt holds its figure much deeper that I'd have ever thought. Those pieces I'm playing with over in the finishing section are an inch thick and look almost exactly the same on both faces.

SR

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...