# My maple top is warped/cupped. Suggestions?



## warped (Aug 24, 2015)

Hi All,
I bought some bookmatched maple to use as a guitar top and it arrived fairly warped/cupped.

I've tried some of the suggestions to straighten it out such as:
1. Heat the convex side to try and suck any moisture out of the wood (I wouldn't have thought there would be any) - I have tried leaving it out in the sun convex side up, leaving it in front of the heater like this.
2. Try to get a little moisture 'into' the concave side hoping it might expand and straighten the wood out (Ironing with a damp cloth on the wood).
3. Tried pressing it on a flat surface with a lot of weight on it
4. Tried pressing it on an un-even surface with weights working against the bow to try and straighten it.

Does this look too warped to salvage? It takes quite a bit of pressure to bend it flat, I wonder if a glue joint would hold it?


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## MaxOfMetal (Aug 24, 2015)

I'm sure the irony is not lost on you. 

Sorry I can't be of more help though, I've always just ditched warped pieces.


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## DistinguishedPapyrus (Aug 24, 2015)

Might try doing what you've already done... but MORE. Steam it up really well and quickly press it flat, like with several clamps against a sturdy piece of stock or a metal beam, let it sit for a couple days to settle. You'd be amazed what steam can do to wood.


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## HaMMerHeD (Aug 24, 2015)

Stack and sticker it with lots of weight on top for a few days/weeks. It won't straighten out overnight.


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## warped (Aug 24, 2015)

Thanks! I'll try steaming it and clamping it flat (for a few days this time).
Should I steam the whole thing/both sides? Or just the convex side?


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## warped (Aug 24, 2015)

MaxOfMetal said:


> I'm sure the irony is not lost on you.
> 
> Sorry I can't be of more help though, I've always just ditched warped pieces.



If beer wasn't so great I could have gone with 'straight-edge' as a username, things might have turned out differently..

Would be an expensive ditch for me:
Curly Maple Top for Flat Solidbodies | stewmac.com


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## mwcarl (Aug 25, 2015)

I think you should be able to still use it, especially if you can get that one board a bit straighter. Glue will have plenty of strength if the joint is good. It will be a bit more complicated to join it cleanly, but there's no reason you can't still use it if it isn't thicker than about 3/8".


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## ThePIGI King (Aug 25, 2015)

Dude, that is perfect for the ultimate archtop guitar. All you have to do is build underneath the wood to its shape and then have it end up flat. Making it look like a turtle, and then you have an archtop without any carving. Bam. Super sick idea, right?


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## Slunk Dragon (Aug 25, 2015)

My guess would be wet that sucker up, and pile loads of weight on it, then leave for a while in a place where it can dry easily, steaming it if necessary.

I think combining the steps you had already done might get you closer, though this is coming from someone who's never had to do this process himself, but has been around woodworking for a good portion of his life. Just my 2 cents!


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## pondman (Aug 26, 2015)

I've glued up pieces similar to that. If it hasn't cracked already with all the methods you've tried the chances are it wont crack if you clamp and glue it.
Put some weight on both pieces for a week and see what its like after that and then if its ok (no cracks and maybe a little straighter) glue and clamp it to the body but try to have the cupped side facing up if possible.
I'm no expert luthier but this has always worked for me.

Btw, cant you send it back for replacement ?


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## dankarghh (Aug 26, 2015)

+1 on pondmans suggestion, though everyone raves about stewmacs customer service. I'd email them, they'll probably send you two new ones for free ')


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## Edika (Aug 26, 2015)

pondman said:


> Btw, cant you send it back for replacement ?



That would have been the first thing to try before attempting to fix an issue that wasn't supposed to be there in the first place. It mentions flat top solid bodies not archtop.


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## TuffyKohler (Aug 26, 2015)

Soak both pieces of wood with a sponge and lay them flat with weight on them. A LOT of weight. 

I flattened way worse pieces. 

Check them every day or so, if they have dried, soak them and press again. 

It took a few weeks to get my walnut boards flat.

Once they are flat, get your work done ASAP. 

Anytime I order wood, I have to press it flat, and I make sure to store it flat, and pressed under weight. Simple changes in humidity with only one side of the wood exposed will let it curl up in you if its not stored properly.


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## neotronic (Aug 26, 2015)

pondman said:


> Btw, cant you send it back for replacement ?



The seller advertises it as being "sized for joining, gluing to a flat body blank, and profiling for a guitar or bass."

You are obviously not getting what you payed for. 


I'd send it back too.


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## warped (Aug 26, 2015)

I contacted Stewmac - they said I can try to steam/clamp it flat if I want and if still not happy they can organise a refund. I'll give it a try and if it doesn't work out the guy sounded pretty reasonable about a refund/replacement.

I might try clamping it with a little reverse bow compared to what it has now and see how it dries out.


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## TuffyKohler (Aug 26, 2015)

I would press it not clamp it... Subtle difference though...


Wood will bend nicely, given the proper environment. 

'Clamping' I'm considering as - your forcing the wood to bend -- in your case you mentioned beyond your preferred shape, in hopes it will get part way to where you clamped it, hopefully flat. 

'Pressing' would infer enough pressure placed on the warped wood so that if the wood wants to, it can become flat. The wood 'wants' to become flat because with the moisture and possibly steam you introduced, it allows the wood to become somewhat flexible, and with the pressure you've applied it will conform to the flat surface you have pressed it too. 

It's really easy to put too much pressure on a warped 1/2 board and crack it using clamps. 

I toss on a few 10lb weights, not so much that it really changes the shape of the warped piece being pressed, but enough to persuade the wood. 

It will take time, and this is a great excuse as to why it's good to have multiple project going on...

Be nice to your wood...


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## mwcarl (Aug 27, 2015)

Thinner tops cupping once you get them is very normal, it's nice that Stew-Mac is offering to replace it, but it's just something builders deal with all the time. You're working with wood and getting it shipped from somewhere with different ambient moisture.


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## Purelojik (Aug 28, 2015)

what i do is i'll cut the top to shape + a few mm .then i'll map out some vertical relief cuts on the underside, they cannot go from end to end but will have to stop a little bit from the outer margins of the body. do this with a dremel router on the underside then steam the top with an iron and foil, then use some heavy weights or a sandbag to keep it flat. 

soon after just glue the top together and glue it to the body. its worked for me many times even with some really cupped pieces


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## warped (Aug 30, 2015)

Thanks guys - I steamed them and endedup clamping them together between some flat pieces of wood - I didn't have anything that was heavy enough to put on top that would flatten it out (40kgs of weights wasn't enough to flatten it and I didn't want to park my car on it.

I'll leave it clamped flat for a few days and see how it goes.

If I can get them fairly flat I'll get them run through a thicknesser which will take ~2mm off the total thickness so hopefully they will be a bit easier to bend in place if necessary and glue down to a body. I'll try some shallow relief cuts too - thanks Purelogik


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## Kammo1 (Aug 30, 2015)

The easiest solution is glue the 2 pieces straight onto your wood base ie mahogany, maple whatever and leave to dry. Then joint the 2 pieces and glue them together, then run it through a planer or thickness sander to youre desired thickness and youre done


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## mwcarl (Aug 30, 2015)

warped said:


> If I can get them fairly flat I'll get them run through a thicknesser which will take ~2mm off the total thickness so hopefully they will be a bit easier to bend in place if necessary and glue down to a body. I'll try some shallow relief cuts too - thanks Purelogik



A couple tips. Remove material from the bottom side of the top (i.e. the non-bookmatched side). That will preserve as much of the book matching as possible. Also if you're thicknessing with a planer and not a drum sander, I would be very careful with figured wood. It is very prone to tearout which will be very frustrating. If you absolutely have to use a planer and are determined to make the top thinner, then take very shallow passes. Even so, there is still a significant risk of damaging the top.


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## J_Mac (May 31, 2016)

Dude, how did this turn out? I have a couple of warped boards here and not sure where to start. 












I'm up for the "clamp-and-glue-it-straight-onto-the-body" approach but don't know how to flatten the boards while they're warped. Or how to join the boards before I take them to the body.


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## warped (Jun 1, 2016)

Hey,
I dampened them with a little water, clamped them flat between a couple of big bathroom tiles and left them for about a month (I ordered another flamed maple top from allied luthiery which was great which is what I'm using for my first build attempt).

After that they were pretty flat. I glued them together, and have kept them on a flat piece of MDF wood with a spare tasmanian blackwood body blank on top so it has a bit of weight on it and it really is very flat now, I don't think I'll have any problem using it now.

Mine is only 4 or 5mm thick, which might be a little thinner than yours. I have left it without any weight on it for a few weeks and it moved ever so slightly, but should be fine once glued to a body.

Try a tiny bit of moisture and clamping it flat for a couple of weeks.. Frustrating when you want to use it straight away, but seemed to work for me


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## warped (Jun 1, 2016)

Second look at your wood - it doesn't really look bad at all. I think it'd glue onto a body fine, try keeping it clamped flat until you are ready to use it. 

I tried steaming, etc - nothing worked except adding a little moisture, clamping for a long time until it dries out completely..


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## Pikka Bird (Jun 1, 2016)

J_Mac said:


> Dude, how did this turn out? I have a couple of warped boards here and not sure where to start.
> 
> [pics]
> 
> I'm up for the "clamp-and-glue-it-straight-onto-the-body" approach but don't know how to flatten the boards while they're warped. Or how to join the boards before I take them to the body.



Your pieces definitely look more straight that warped's ... warps. I think you'll be fine, especially if you moisten it and weigh it down between two confirmed flat surfaces for a week or so before you go to the clamps.


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## J_Mac (Jun 1, 2016)

Cheers fellas, I'll have a crack at that \m/


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