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A year or two ago I obtained a B&S set of Ziricote. I foolishly did not sticker and or weight down the set. I now have some expensive cellulose potato chips. In defense of my actions or should I say inactions. I hadn’t realized or thought that this wood is plain sawn.
So what is the best way to flatten out and straighten the back. Should I pre flatten the sides before bending? How much moisture should I use in the Fox bending machine for the sides? Also is this wood really wise to use in acoustic guitar construction. I.e is it stable enough for this?
Any advice, techniques or suggestions would be greatly appreciated.


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"It is easier to fool a man, than it is to convince him that he has been fooled"
Mark Twain

In my somewhat limited experience with that situation, I have never been able to get it to return to a shape I'd be willing to build with. You hear lots of advice about ironing it, soaking it and putting it under weight on a concrete floor, but IME they've always returned to Old Dutch...

Previously I posted my experience with a set of BRW.

First, if it has wax, do not heat it. The was will flow like water into the wood and never come out. You might not see it, but it can compromise glue joints.

I straightened it by soaking in water for a long time. Maybe 10 days-I do not recall. It relaxed back to the natural shape, whereupon I stickered it properly. It was no help to try to weight it down wet until it soaked long enough to relax on it own. For the sides, which did not fit in the laundry tub, I built a little trough on the basement floor with pieces of 2 x 4 and just draped a heavy duty plastic bag over the wood. I held the BRW under water with metal weights sealed in plastic bags so they would not transfer rust to the wood.

As others said, no wax please.
FWIW, I successfully flattened a warped zircote back, soaked it in SSII overnight (saran wrapped), wiped off excess, little spritz H2O, wrapped it in alufoil and ironed it flat with a domestic iron on the workbench. Did this from on sides of the plate, got it good and hot.
Stickered (3 sets of 5 stickers, under, between and over) and weighted it flat immediately - 2 years ago - still stickered, still flat.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Plain sawn wood has a tendency to warp and crack - eventually. That's just the way it is. Some woods are worse than others. Ziricote is sometimes called "Mexican crack wood". It is beautiful and many people build guitars with it. BRW is said to be more crack prone than East Indian rosewood, but people still find it more desirable. Even perfectly quarter sawn wood will crack under adverse conditions. The conditions the guitar is build and lives under to a great extent determine it's stability.
A lot of old parlor guitars have developed cracks over the years. Finding one in pristine condition is the exception rather than the rule. Cracks can be repaired, sometimes inconspicuously and sometimes the repairs are obvious.
If you build with plain sawn wood, know that it will require a little better care, and that it may crack. We picks our poison and takes our chances.

Situations like this can bring creative responses.

I had some BRW that behaved is a similar manner. It wasn't terrible but it wasn't great either. I certainly didn't trust it to behave over time as a guitar, and that's enough reason to reject it. But, it was expensive so I got the old thinking cap on...I joined the back, then sanded it down to just over 1.00mm thick. The machine held it flat long enough to sand it. I ended up with a very attractive sheet of bookmatched BRW veneer. This I then cross laminated with khaya, spruce, khaya and maple veneer. In that order. The centrepiece of spruce was a reject soundboard. Waste not, want not. The sides I did the same with but bonded those to a manmade material I was using at the time.

I ended up with a magnificent looking and sounding guitar, made from a rather expensive ply!

What I'm saying is - you don't have to make a "normal" guitar with the wood. You can make something very lovely and a little more stable than you might otherwise.

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nigel

http://www.theluthierblog.com

Nigel wrote:
"I ended up with a magnificent looking and sounding guitar, made from a rather expensive ply!"

I'll bet that was some expensive Ply! I'm glad you were able to make use of the wood.

A number of years ago I bought a couple thousand sq. ft. of BRW flitch matched veneer "off fall" for scrap veneer prices. I reglue the layers back together in the order they were cut and it makes lovely guitars. It's one way to keep costs down and does make flatsawn wood (veneer) more stabile.
If I paid good money for a set of back and sides I would be reluctant to sand it down to veneer thickness. If I was worried about the stability I might build a -smaller - instrument (parlor guitar, a couple of tenor ukes, mandolins, etc.) and get some bindings, head plates, and other odds and ends from it. Usually it is the stresses created by the cross grain gluing of the braces that causes the biggest problems so narrower instruments suffer less. With flatsawn lumber there is also a tendency to cup or twist - in a narrower piece this can be controlled better. If the set has a side where the grain is more vertical that can be selected for the center of the back and the off quarter wood kept to the outside.

Thanks to all of you for the experience based suggestions and creative ideas. This set might become a parlor size guitar. If I successfully coax it back to flat.


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_________________
"It is easier to fool a man, than it is to convince him that he has been fooled"
Mark Twain