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My one and only set of BRW, graciously provided by John Arnold 10+ years ago in trade for a small stack of tops. Not getting any younger so time to use it. Was wanting to build a 000 cutaway. Problem is that the sides have flaws so I'm looking for some input on how to stabilize the wood so I can bend it. I've thought about a few things like maybe thin the sides to about 0.065" so they'll bend easy, fill the voids with something?? and glue paper on each side.

Anyway, what do you good folks think might work? FYI I use a bending iron.

This is near the waist.


This is at the neck end.

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Steve Smith
"Music is what feelings sound like"

If that crack is right on the waist then that's gonna be tough but if you can move it away to a more flat section it would be ideal. I've not bent wood like that before I I'm interested in what others have to say too. Sounds reasonable to me that gluing brown paper on each side might help. Perhaps pressing with a thin steel slat.

EDIT: I see now one of the cracks is at the very end/ Probably wont have to worry about that one if it's up at the neck joint and you profile the sides first.

I was thinking I can get the one by the waist a few inches away from the waist centerline. I will measure it and see.

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Steve Smith
"Music is what feelings sound like"

If those sides are as wide as they look, make a side profile and see if you can cut any of the bad spots off before bending.

Coming from violins, and even on my cello, I never bent ANYTHING even that thick. 1.5 mm and under, even for cellos. Even a top maker in Chicago recommends under 1.5mm for cellos. Yeah cellos aren't 1 piece per side; but they are 5" wide. I bent the 3/8-1/2" radius on the arm of my ElectroLess Paul at under .03" The rest was .05 or less in the waist and cutaway. I would definitely thin the knots near the waist out on the inside.
I was going to use paper on the tight corner I did, and forgot to glue some on. It worked, but gluing paper is easy to do.

You can bend solid linings to add stiffness.

Near the waist isn't as bad as right at the waist. But sometimes you are switching from concave to convex. What side do you glue the paper on there? Both? The neck part should be fine. Get it thin there. It is over the block anyway.

I just thought about this. You probably are thinning on a drum sander? Sand them down to .065, and see how it feels. I would go to .05, but I'm crazy. But BRW has to be stronger than the .48 sg Big Leaf maple of my cello ribs. Then I would thin the worst areas by hand if they don't seem to bend as easy as the rest just by hand without heat.

Luckily, your stock doesn't look real wavy, even near the knots.

CA in the crack at the waist? I don't know about that. It is something that I might try. Again. I'm crazy.

I'm sure that you will get some cracking. At least by the knots. Maybe really thin there, and super soft or windex. I haven't used them but it did use borax water. Why? I'm crazy.

I hope others chime in.

Ahh. I like the cut off extra width.

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Why be normal?

That’s a good idea, guess I need to measure things a lot closer. They are about an extra inch wide but if I trim them that would leave some sapwood showing.


Steve

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Steve Smith
"Music is what feelings sound like"

Ken, thanks for the ideas. I’ll see how it feels and go thinner if I’m comfortable with it. Paper will go on the outside of the bends. I use SuperSoft pretty routinely so yes to that one.


Steve

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Steve Smith
"Music is what feelings sound like"

I'm concerned about those two crosswise lines circled in the first photo, and another in the second: they look like 'wind shake'. The name is misleading: it's actually felling damage that comes about when the falling tree hits something hard, like a rock or another tree trunk. The wood is compressed along the grain, and the stress is high enough to exceed the it's strength: it's already broken and will simply 'brash fracture' if you try to bend it. DAMHIKT

If the sides are as wide as they seem, and you can trim out those lines, you could be OK. I've 'tricked out' narrow sides by gluing the liners a bit proud of the edge: you cover up with the binding.

One caveat I would make to that point for guitar builders is that going that thin can be problematic for some highly figured woods that won't bend flat. If the surface ends up ripply instead of flat, you may not be able to sand it level to true up the sides without sanding through. Guess how I know.

Steve's side wood doesn't appear to have much figure so maybe he could get away with going very thin with that set.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Personally, I love sapwood, and if it was my set I would specifically try to have it in there.

As mentioned, if you can get those areas even an inch or two on either side of the waist, there’s minimal bending there.

You may also consider going thinner to .055- .065 and laminating them…

Good comments all and thank you! It may be that, as Alan said, the wood might fracture. Regardless, I will attempt to bend them since they are of no use to me unless I can make them into a guitar. If I can get the waist bent I may call it good and not go for the cutaway, I'll make that call on the bending iron. The sides are at 0.092" right now so I'll see how they feel as I thin them down. I did make a template and was able to get the uglier spots outside of the pattern.

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Steve Smith
"Music is what feelings sound like"

Make sure you cut those ugly spots out before you bend. those breaks will make the stiffness uneven across the side as you put it on the pipe. The stress will be concentrated there and one of those broken parts can cause a break to move into the good area.

Sometimes I think about gluing on paper if I am even a little bit concerned. I think it is a great idea and costs very little. Then I wonder how SSII will work with paper glued on. Will it effectively migrate through the glue into the side? Will it cause the glue to fail or just be too soft to be effective? I suppose I should do some experimenting.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

I found SS2 to do nothing on BRW YMMV. It looks as if those cross grain cracks that I thought I say and Alan commented on were just pencil marks then? If so then it looks like those knots are well out of your pattern.

The only sides I ever broke bending was a set of beautiful old growth BRW. I built my first guitar 25 years ago and always told myself I would wait till I think I am 'good enough' to build whit BRW. That day came and... Snap!!!!!!!

I about fainted. I got the yips so bad I could no longer bend wood so I bought a machine specifically to bend this very expensive BRW. Turns out, after a thread I started that Alan was kind enough to comment on, it was Brash Wood which meant it was broken when I got the stuff but you could not see it. I started at the waist first and barley applied pressure and the entire piece snapped right across the grain into two pieces.

Anyway if you want to drive up north on 81 a couple hours you can use my bending machine if you think it will give you peace of mind

I had a set of EIR sides with brash cracks like that. As Alan said, they are already broken. If the cracks fall within the template, even if you can bend them (possible with paper on both sides, using HHG and bending not long after gluing, keeping the cracks on the flats - [the moisture from the glue helps the bending]) you still have to get the paper off, which means water, which means your sides will likely ripple. And you still have a set of sides that are broken and look like it, because the cross-grain line will still be there. If you don't mind the look, your best bet at getting a set of sides that will hold together is to laminate them.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

I would agree with lamination. Profile before bending to get rid of as much bad wood as possible. Maybe thin to 0.050 or so. You could use IRW for the inner side. It’ll be a sphincter tightner.

Let us know how it goes. Good luck!

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Ok guys some good advice here.

Bryan, ugly spots are outside of the pattern now and will be cut out.

JF, I’ve got two side benders, I just prefer hand bending but the bender may get used this time. Thanks for the offer though!

Trevor and Terrence - recommendation to laminate noted.

I’ll go down tomorrow and get the Optivisor out and check for brash cracks. If I find them then I’ll try the laminated approach. I have plenty of IRW sets and a good commercial vacuum pump. Bending would be on the side bender so the shapes would match exactly. I just hate to let this BRW go to waste and am willing to do some extra work to save it.

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Steve Smith
"Music is what feelings sound like"

I would glue veneer strips to the inside of the sides where the cross grain fractures are. It may not bend as smoothly in those areas but if it holds the fractures together you could possibly bend at a normal thickness and smooth the curve by sanding.

That’s an interesting idea Clay, something for me to think about.

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Steve Smith
"Music is what feelings sound like"

Success, got the sides bent! I seriously considered laminating the sides but after I got them thinned and trimmed I felt like they should bend ok. Thinned to 0.065", no SuperSoft. Set the bending iron at about 330F and used a wet paper towel on the waist. I did put paper patches on the fractures on the lower bout that I couldn't cut out; I only put patches on the outside of the bend. Patches were just lightweight brown painters paper and CA.

Thanks to everyone who responded for your help!!

Here's the patches




And here's the proof

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Steve Smith
"Music is what feelings sound like"

Awesome! I'm glad it all worked out for you.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Excellent!

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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.

Sweet! It's nice looking rosewood.

That’s a great idea and looks like it worked perfectly.


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I have successfully bent Brazilian rosewood and mahogany with these so-called cross-grain 'brash fractures'. That tells me that the stress occurred while the tree was still growing, not when it was felled. That is an indication that the crack is healed, at least to the degree that steam bending won't open it. In most cases where I have employed such wood, it has not presented an issue.
I have a stack of 'reject' Honduran mahogany backs with a few of the same jagged cross-grain lines, and I would not be afraid to use them if they pass a stress test.


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John

I have not run into much fractured wood in lutherie although I did see it sometimes when I worked as a carpenter. Since these sides bent ok then these fractures must have occurred while the tree was growing, as John said.

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Steve Smith
"Music is what feelings sound like"