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I received a couple of very nice sets of EIR about a month or so ago. I am now ready to use one, but there is a problem. My shop is temp and humidity controlled (approx. 45% RH), and the back has been stacked flat under pressure since receiving it. How long should I have to wait before this flattens back out? Is there anyway to speed the process? The other set I received has the same problem, just not to the same degree. The back set at issue has is sawed quarter to flat. Thanks in advance for the advice.

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Aaron Craig

You can iron it flat with and iron.

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http://goatrockukulele.com

I realize I did a poor job describing the problem. I tried to edit the post, but that time has apparently past. Anyway, the set is badly warped. If you were to lay the set on a flat table, at the center, the pieces dome up about 1 inch. Thanks.

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Aaron Craig

Really? I will give that a try. Have to be sure the wife's not a round. Wouldn't want her thinking I've become proficient with an iron.

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Aaron Craig

If it's just cupped into a cylindrical type of bend with both edges reasonably even, moisten, lightly, the concave side and put, convex side up, it on a concrete floor. It may flatten itself out. If that doesn't work, Ironing may work. I've had some Cocobolo, that I could not take all of the "potato chipping" out, even with an iron. When thinned, though, it was very manageable, and worked fine for a back.

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Waddy

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I would rather forget about it at least 6 more months.

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Build log

So would I, but I don't see that as a viable option. I can and probably will wait a month or two, but that is probably the limit. I am starting to stock up on tonewood for the future. So hopefully this becomes less of a problem. Right now, I need to use what I've got or twiddle my thumbs. I'm not a thumb twiddler.

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Aaron Craig

How thick is the back? If it's about 3/16" or more, you will have a problem ironing out. You will have better results with what Waddy suggested. You can even clamp it between two hard boards (plywood would work fine). Go gently on the clamping, tighthening it every hour or so until the board is flat. Let sit for the night.

This worked for me when iI got into the same problem you have.

Good luck!

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

I had a set of Australian Blackwood Ukulele sides that I had bent, and decided to use a different set. So I ironed them out using an iron, and it worked really well. I also have an EIR set that still is warped after a year being stickered, and I planned on ironing it straight.

Glenn

There is more than enough great quality EIR around to not buy flat sawn stuff, I am surprised, does it come from a seller on eBay?
Conundrum: if it is too thick you can't flatten it with an iron, and you can't pass it through a drum sander without losing a lot of thickness.
I'd buy another set, perfectly quartersawn this time, and build with it. It's always best to wait as long as you can before building with your tonewood. If it's not an option, buy well cut and well seasoned wood from a reputable dealer.

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

I would return a set that had severe racking as you describe.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Thanks for the comments. The wood came from a very reputable tonewood supplier. I let the guy I'm building for select the set he wanted. While I wasn't too pleased with the selection, I figured it would work. It is more quartered than flat sawn, and I've used similar stuff before. I imagine with some time, the set will flatten out. I will try wetting the concave side per the advice above, before ironing. I will also be much more hesitant to buy anything but perfectly quartered EIR in the future.

Related Question: How flat is flat enough? Once the back is taken down to thickness, there is a fair amount of flex. Is it acceptable to just force the back plate into braces and clamp to the sides? I would think it would take a pretty fair amount of torque coming from the back to cause problems, but my experience is limited.

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Aaron Craig

Absolutely. If you can flatten the back with simple finger pressure, don't worry about it and brace the thing up!

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

It's not the torque coming from the back that causes problems. The reason it curves is because it's shrinking. If it's braced, then shrinks it will crack. Without looking at, and feeling the back I can't say whether it's OK or not...............and I'm not an expert anyway. I'd recommend weighing it. Wait a week and weigh it again. If the weight changes it's still.....moving. If the weight stays the same for a week try ironing it flat and see what happens. I understand that you don't want to twiddle your thumbs for 6 months, but I doubt you want to be repairing cracks in the future either. Don't use any wood until it's ready to be used.

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