Warped Flame Maple Tops

[rdiquattro]

About two years ago i bought two flame maple bookmatched tops at 28mm thick .

Just the other day a had a close look at them and they have become severly cupt like this ( across the width of the board .

Both sets of maple are perfectly quatersawn , does anyone have any sugestions on what i should do with this maple they both cost me alot of money. Any help would be greatfull :D

[SnowGTR]

I’ve dealt with this problem several times. When a board is resawn to make a book-match and it is not completely dry, it often will warp or cup. It caused by releasing stress on one side of the wood and not on the other. Boards should be book matched when completely dry (about 6%) or when green. When thinning a board it should be done by removing wood from each side of the wood at an even rate. Unfortunately if you have a 1”+ thick boards, as you plane down each side you will loose your book-match. So to retain the book-match I thin the wood on one side only (the B side) but this can cause the wood to cup or warp. To get a flat top to bond to the back I use plywood that is flat and a little larger than the maple. Then in each of the corners of the (B side) maple I put a dab of bondo. Then set the maple (b side) down on the plywood and while the bondo is soft adjust the height of each corner so it is the same. Then after a few minutes I run it through my drum sander or planner. Now my wood is flat on the money side and i can plane down the other side to my final thickness. If the wood is not dry it will start to cup and warp again.

Hope this helps.

[fryovanni]

How much has it cupped? and is it cupped tward the book match or away?

A few things about wood and drying. First of all, depending on the ambient humidity where the wood is stored vs where it was originally cut. You can have drying or absorbtion of moisture. In some areas the normal humidity levels may only allow wood to reach 10-12% moisture, in other areas(very dry climates) it may stabalize at 6%. This is important to understand because if you recieve totally stabalized wood from a dry climate and your climate normally is much more humid. The wood will aclimate(raise its moisture) till it has reached equilibrium. This is why you should always weight and sticker wood when you first recieve it(and allow it to stabalize for several months). It is also important to allow air to circulate equally to all sides(obviously stickered it has air flow, but also if you stack after it has stabalized try to aviod allowing air to one side and the other exposed). After wood has stabalized you it will still be subject to normal seasonal humidity changes, but these are not going to have a major effect(unless you have a very radical climate).

As far as surfacing. Try to remove as little wood from the bookmatch as possible. Depending on how much cupping is going on and your equipment there may be a couple options. One thing that is in your favor is that well quartersawn flame maple(if figure is strong throughout) many times has a very good match even when you sand away from the bookmatch.

Out of curiosity. How was the wood stored? Did you move or relocate it? Who did you get it from? Was it advertised as musical grade stabalized wood? It can be really tuff to tell if the seller knows what they are doing these days(ebay can be a crap shoot). I have seen people selling musical grade wood that is 20%+ moisture. I have also seen dealers that sell straight up green wood, but are very honest about it(although many times they charge as much as well stabalized wood).

[rdiquattro]

I’ve dealt with this problem several times. When a board is resawn to make a book-match and it is not completely dry, it often will warp or cup. It caused by releasing stress on one side of the wood and not on the other. Boards should be book matched when completely dry (about 6%) or when green. When thinning a board it should be done by removing wood from each side of the wood at an even rate. Unfortunately if you have a 1”+ thick boards, as you plane down each side you will loose your book-match. So to retain the book-match I thin the wood on one side only (the B side) but this can cause the wood to cup or warp. To get a flat top to bond to the back I use plywood that is flat and a little larger than the maple. Then in each of the corners of the (B side) maple I put a dab of bondo. Then set the maple (b side) down on the plywood and while the bondo is soft adjust the height of each corner so it is the same. Then after a few minutes I run it through my drum sander or planner. Now my wood is flat on the money side and i can plane down the other side to my final thickness. If the wood is not dry it will start to cup and warp again.

Hope this helps.

Thankyou for your help everyone it is much appreciated , Only one question snowgtr what type of glue is bondo , i have never heard of it before what is it close to. The timber im talking about i bought from ebay ,the seller said that it is for guitar building ,and we did have a very hot summer this year . When i bought the maple i had it stored in the house and now its in the work shop . So that i think has had alot to do with it .

[fryovanni]

I’ve dealt with this problem several times. When a board is resawn to make a book-match and it is not completely dry, it often will warp or cup. It caused by releasing stress on one side of the wood and not on the other. Boards should be book matched when completely dry (about 6%) or when green. When thinning a board it should be done by removing wood from each side of the wood at an even rate. Unfortunately if you have a 1”+ thick boards, as you plane down each side you will loose your book-match. So to retain the book-match I thin the wood on one side only (the B side) but this can cause the wood to cup or warp. To get a flat top to bond to the back I use plywood that is flat and a little larger than the maple. Then in each of the corners of the (B side) maple I put a dab of bondo. Then set the maple (b side) down on the plywood and while the bondo is soft adjust the height of each corner so it is the same. Then after a few minutes I run it through my drum sander or planner. Now my wood is flat on the money side and i can plane down the other side to my final thickness. If the wood is not dry it will start to cup and warp again.

Hope this helps.

Thankyou for your help everyone it is much appreciated , Only one question snowgtr what type of glue is bondo , i have never heard of it before what is it close to. The timber im talking about i bought from ebay ,the seller said that it is for guitar building ,and we did have a very hot summer this year . When i bought the maple i had it stored in the house and now its in the work shop . So that i think has had alot to do with it .

Bondo is auto body filler.

How severly cupped is the wood? (say you put a straight edge across it, how far off would it be in inches or millimeters?)

[pmarlin]

Im guessing the climate change had something to do with it. I bought some off ebay and when they got here they were fine. I put them out in my shop and the next day they were cupped but after a week they flattened back out.

[Jon]

Last 5 boards I ordered did the same thing. It's very important to let them acclimate or one could damage or ruin the wood completely.

[rdiquattro]

I’ve dealt with this problem several times. When a board is resawn to make a book-match and it is not completely dry, it often will warp or cup. It caused by releasing stress on one side of the wood and not on the other. Boards should be book matched when completely dry (about 6%) or when green. When thinning a board it should be done by removing wood from each side of the wood at an even rate. Unfortunately if you have a 1”+ thick boards, as you plane down each side you will loose your book-match. So to retain the book-match I thin the wood on one side only (the B side) but this can cause the wood to cup or warp. To get a flat top to bond to the back I use plywood that is flat and a little larger than the maple. Then in each of the corners of the (B side) maple I put a dab of bondo. Then set the maple (b side) down on the plywood and while the bondo is soft adjust the height of each corner so it is the same. Then after a few minutes I run it through my drum sander or planner. Now my wood is flat on the money side and i can plane down the other side to my final thickness. If the wood is not dry it will start to cup and warp again.

Hope this helps.

Thankyou for your help everyone it is much appreciated , Only one question snowgtr what type of glue is bondo , i have never heard of it before what is it close to. The timber im talking about i bought from ebay ,the seller said that it is for guitar building ,and we did have a very hot summer this year . When i bought the maple i had it stored in the house and now its in the work shop . So that i think has had alot to do with it .

Bondo is auto body filler.

How severly cupped is the wood? (say you put a straight edge across it, how far off would it be in inches or millimeters?)

Across each peice it has a cup of about 3mm aprox.

[fryovanni]

Across each peice it has a cup of about 3mm aprox.

Ok, about 1/8" is not that bad at all. I am assuming you are looking to use these for a carved top so you should have plenty of room to surface and use them(you mentioned the set was 28mm, a little over an inch thick). The most effective way to suface(if it is just cupping-*not twisted). Would be to surface the back side for the boards flat(that way you have a solid flat reference for the front surfaces). Then surface the bookmatched side. If the cupping is only 1/8" and the wood is well quartersawn you should not have a bad match. I am assuming you have a thickness sander. If not a local cabnet shop could do this for you for a nominal fee.

If you try it by hand(assuming you are good with planes) take your time and don't over due it or wobble the board. Be sure to square your sides before joining(and reference your good flat surfaces you just created). The sides will be a bit out of square when you are finished surfacing(but should be pretty close) so get them tight before you glue. Personally If I did this by hand I would surface the back to square, true the sides, joint, and then make final adjustments to the top. There is usually a slight loss of alignment during joining, so waiting to surface the bookmatched side would allow you to surface it one time(I should note it is critical that you evenly surface the backs so the pieces are similar in thickness- else you will lose a lot more of your bookmatch after joining).

Peace,Rich