LP build (OK assemble!) maple cap question

MrP

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Over the last week or so I've started to work on some CNC LP parts I've gathered over the last few months.

I've noticed something about the maple cap & should I be concerned about it?

when I lay it on the back piece (or any flat surface) I've noticed it's ever so slightly warped, not along the centre line (ie from the neck to rear straplock point) that's perfect but perpindicular to the centre line at the furthest points both sides have 2-3mm gap above a flat surface.

It will clamp flat, but is it something I should be worried about?
If I glue it as it is over time will it revert to it's warped state or will the glue hold it in place?
Or what kind of glue should I use to keep it flat?

Should I attempt to 'flatten' the cap before I use it & if so how would I go about this?

As always thanks in advance
 

cherrick

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Steam it and then clamp it flat. Let it sit. Repeat as necessary.
 

WhiteEpiLP

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2 to 3mm, just glue and clamp the hell out of it. It will be fine.
 

pshupe

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That's not very much. I have placed a damp cloth on the concave size and it comes out nicely. You may just want to put the concave side down, if you have been laying it flat. It will lose more moisture from the top side and will cup to that side. I've taken 1/2" out of a bookmatched top with the wet towel method. Get it flat, glue it fast, then carve it. Once it's carved there isn't much wood left to move and a very large glue joint.

Cheers Peter.
 

MrP

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That's not very much. I have placed a damp cloth on the concave size and it comes out nicely. You may just want to put the concave side down, if you have been laying it flat. It will lose more moisture from the top side and will cup to that side. I've taken 1/2" out of a bookmatched top with the wet towel method. Get it flat, glue it fast, then carve it. Once it's carved there isn't much wood left to move and a very large glue joint.

Cheers Peter.
So if I just clamp it & place a damp towel over it for say a week this may be all I need to do?

btw it's already carved it's a cnc carved top
 

pshupe

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So if I just clamp it & place a damp towel over it for say a week this may be all I need to do?
You don't have to clamp it. Try a paper towel that is moist. Place it down on a flat surface and place the top concave side down on top of the damp towel. Check it in a few hours and see if it is flattening out. I used a very damp towel once and the top cupped the other way about the same amount that it was going the other way. Experiment a little bit.

Cheers Peter.
 

MrP

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You don't have to clamp it. Try a paper towel that is moist. Place it down on a flat surface and place the top concave side down on top of the damp towel. Check it in a few hours and see if it is flattening out. I used a very damp towel once and the top cupped the other way about the same amount that it was going the other way. Experiment a little bit.

Cheers Peter.
great, almost seems too simple, I'll try it this weekend when I can keep an eye on it

thanks
 

pshupe

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yeah - I was suprised how much it moved in a short period of time. The wood takes on moisture and expands. That should take out the cup. Because you will be gluing to a body the glue will hold it from cupping back when the moisture comes out of the wood. Also I would recommend carving the top soon after the glue has cured, just to be on the safe side.

Regards Peter.
 
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MrP

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yeah - I was suprised how much it moved in a short period of time. The wood takes on moisture and expands. That should take out the cup. Because you will be gluing to a body the glue will hold it from cupping back when the moisture comes out of the wood. Also I would recommend carving the top soon after the glue has cured, just to be on the safe side.

Regards Peter.
Peter you are a @%&$ing genius!

I took an old shirt cut the back panel out, ran it under the tap & wrung it out as much as I could.

Clamped the cap flat & draped the ever so slighty damp cloth over it, an hour or so later took the clamps away & it's perfectly flat

Thanks!!
 


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