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Well, it's the first time I have this problem...
I ordered some back and sides, and received it yesterday. First, I open the package (so excited!), and then check the wood before untape it: from the end grain, I see the wood is little curved (don't know the excat term in english..). but, It's not that much, it'll be OK! So, I untape it. It springs a little bit, again, not that much. Check out the bookmatches and everthing. When i came back maybe, 1 hour later, it saw the problem was amplyfying, so I retaped it for the night. This morning, I think the wood is more stable, and is not moving much, but, it's really curved for some pieces, and i'm scared that it could be unrecoverable. I stacked it this morning, with some bricks over it, and then i'm waiting to see... Few questions:

1- The problem come from...? I'me sure the stock was straigh and plane when shipped. I'm sure that humidity here is OK (45-50-55)

2- What is the better process when you receive wood? Let it packed and wait few hours/days, to let it acclimate; unpack it and stack it right now?

3- Is there solutions to recover backs and sides that are curved?

thanks!

Francis

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Francis Richer, Montréal
Les Guitares F&M Guitars

Disclaimer: I'm not an expert.

When taped together for shipping the sides facing outward are subject to gain or lose moisture at a different rate than the sides taped together. Sit the pieces on a shelf out of your way somewhere with the bowed side up. This side is "wetter" than the other side. As is acclimates is may chage directions. Keep flipping it with whatever side is bowed up until it's stable. If it's really bad stickering it may cause it to crack unless you do this first.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Francis -is the wood quatrersawn, or slab-or a bit of both?
Did it come from a dealer in a humid location?

Sticker it and weigh it down and let it get used to being in your shop (acclimate)
Contact the place you bought it from and ask what their humidty is held at in their storage area.
The wood should be fine if it's quarter sawn.
It may take some time for slab to recover.

Mike

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Mike Collins

Pretty common, especially when tonewood has been subjected to different RH ranges during shipping. I usually lay the pieces flat on my bench overnight without any weight over them. It may take a few days for some pieces to acclimate.
I only had one set so far that didn't flatten out (after over a month) and the vendor graciously took it back. I could have flatten it with a clothes iron and some moisture but chose not to, the set was a tad too off-quarter for me.

I'd recommend against putting weight on a cupped set since it can start cracks. I'd put weight on the sets after they've flattened, but that's just my opinion.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Well, it's quarsawn. And it comes from a controled place, that's for sure. But I don't know at what level of humidity the wood was when shipped.

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Francis Richer, Montréal
Les Guitares F&M Guitars

Ok, it encourage me a little bit. I'll wait and then see. But, if the problem persist, heating with little bit of humidity and then put some weight on it could work to flat them?

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Francis Richer, Montréal
Les Guitares F&M Guitars

I have a set of Coco that looks like a pair of airplane propeller blades. It was stickered in my shop for over a year. When I took it out, the wood twisted right up. It was flat when I put it in there. It is quartered in the center, where the back joint will be, but goes out at the edges. Probably from a small tree, or something like that. I have tried the iron, the heating blanket, water, no water ..... nothing seems to work.

And, my shop stays, mostly in the 40 to 55% RH range.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Thanks for the encouragment Waddy

The fact is that i'm in a lutherie school, program of three years, where we'll build 1 uku and 3 guitars (2 class, 1 acoust). I'm still in the first year, working on my uku. And I bought the wood for the 3 next guitars right now, to let them dry and acclimate. So, I can't wait 1 year to see if the problem persist or not, and also, I can't buy too much sets 'cause, you know, paying the studies, the tools, appartment, food, working part time to pay all this...

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Francis Richer, Montréal
Les Guitares F&M Guitars

What wood is it?

Mc

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Mike Collins

It's Curly Maple. 2 sets of back and sides.

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Francis Richer, Montréal
Les Guitares F&M Guitars

If it is a quarter sawn piece you can just put it somewhere in the open on a bench or shelf and let it warp one way turn it over and watch it cup the other way and keep going back and forth till it stops. If it was a poorly cut piece of wood in the first place it will take the shape the grain structure deems as its natural state. I would not put any weight on a thin piece of wood, and would contact the supplier you got it from and let them know that the wood is doing what it is and take pictures. Tell them you will do everything you can but if it does not go flat ask them what they want to do about it.

It is normal for wood to move and am surprised you've never encountered this before. I've laminated table tops and forgot to cover them over night and came out to the shop to them being cupped about two inches. Turned it over and left it for a couple hours and it went back. The best thing is just not to freak out and do something that will destroy it like put excessive weight on it.

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Disappointment is an empty box full of expectation

Thanks for the reply.

On wich face should I let it lay? the sides or the center should touch the surface?

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Francis Richer, Montréal
Les Guitares F&M Guitars

Sides.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Why not contact the vendor for assistance? As I recall, you live way north. RH is probably quite low there, even though you prolly control inside. Most sets I order are completely wrapped in plastic. That seems to help.

Mike

Maple and especially figured maple is notoriously unstable and tends to move no matter what you do. I have some quilted and some curly in my shop and it looks like a miniature roller coaster ride. Well, maybe I am exaggerating, but you get the idea, it's wavy. Sticker it up with some weight on it and hope for the best. It will probably be a test for you until it is bent and braced, then it will be fine.

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"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

Thanks everyone!

I let them on a bench since 2 days. And I have to turn them 2 or 3 times a day 'cause they move in the other direction. anyway, for me, it's a good news. And now I was I can expect when recieving maple. By the way, I recieved a hard maple neck blank some months ago (for the acoustic i'll build with the curly maple) and I remarked that the blank is curving too. I guess I should do the same thing and all that'll be ok? It's non-figured (no curly, no quilt, ne flame) hard maple.

BTW, I contacted the supplier, that's the first thing i've done. And finally, he explained me the particular unstability of figured maples, as you told me...

Thanks again!

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Francis Richer, Montréal
Les Guitares F&M Guitars

In most cases the wood is "shocked" by the sudden change in RH. Let the wood acclimate you your area and stabilize. Yes you may have some propelling in the back but that may go away . See if you sticker and weight it down flat . Every once in a while I get a set that does this. Usually once it is braced , it will be fine. I will heat it , as I have a special heat blanket that fits back sets and heat it up to 350 for 10 minutes and let it cure off.
You may be able to use an iron. I am pretty sure it should look much better in a week or so. keep us posted.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Thanks for the suggestions John!

Today I brang the wood at school, were i'll stock it. RH is more exactly controlled there, and that's where i'll work it so... And one of my teachers told me about figured maple. He's used to work with flame and curly maple 'cause he's a violon maker. He told me exactly the same thing as some of you. First, maple is unstable. The wood probably arrived a bit too wet, had a shock. He told me to put them on sticks, sides of the cupping down, and put heavy weight (not too heavy to crack it, but...), and let them acclimate and flat themselve. As he told me, they'll probably never come back pertecly straight and flat, but, it should be okay when sanded at his thickness and braced.

so that are good news. And good learning for me.
And, hey, I'm happy, 'cause these set are awesome!
Can't wait to build this curly maple dread cutaway, maple neck, Adi top, Ebony FB

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Francis Richer, Montréal
Les Guitares F&M Guitars

This happens to me all the time.

If the wood is wrapped in plastic I leave it in plastic for a week or so and put a weight on it, then take off the plastic and keep the weight on it for another week. That usually does the trick. After that it generally remains stable and flat and I then sticker it for a couple of months before moving it to the shelf.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Thanks, i'll remind this..

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Francis Richer, Montréal
Les Guitares F&M Guitars