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Hi, I am starting my second build and acquired some very nice highly figured Koa.

300 good on the temp?

I tested SS II on a piece of EIR and it stained the wood really bad. I used the LMI bender and wrapped the wood in aluminum foil. I'm not sure if it will sand out. Is that normal? I don't want to mess up this very expensive wood. Maybe I should use distilled water?

I only use distilled water in my shop.
I put brown paper next to the wood then foil. I believe the stain was caused by the foil.

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Distilled water, brown paper and no foil or be 100% sure the paper is acting as a barrier for the foil. I just did a koa baritone uke and had some very faint staining that I got rid of but it was a close call.


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I use aluminum foil because it helps keep the steam contained but you also want some sort of paper material (I use regular unmarked paper towels) between the wood and the foil. Koa usually bends easily but with figured woods, it helps to keep the sides thin and make sure you support the bends well or they will fracture because of the extreme runout. One of the many positives for using laminate sides -- makes bending figured woods less stressful.

Thanks, I'll try paper between the wood and foil. I have steel on each side so, hopefully, that's enough support.

I mostly work with koa. I tried foil once and will never do it again. You don't need it. Never had any issue with my water, so I have no need for distilled water either.Definitely use no Windex or other ammonia bending aid. The paper wrap, wood not too wet, stainless steel slats top and bottom (absolutely no regular steel unless you like koa that has a greenish to black color stain} tightly against the wood,a bending blanket, and you're good to go, slowly! I start bending at about 275 degrees and my controller is set to 320 degrees for 10-12 minutes. Takes me about 2-3 minutes to do the bending, so the wood cooks for 7-10 minutes. I put a fan on it from under the mold to cool it fast , and if there is springbuck when I start to open the mold I close it up and run the temp back to 300 degrees and turn it off as soon as it reaches 300. Then I just let it cool naturally, unless I'm in hurry, in which case I use the fan again. If you have not bent curly koa before, you might want to start with some other practice wood. Give us a photo of the wood and maybe someone can give more advice. Good luck.-Bob

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Where is your blanket located in the stack?

300-315 start bending at about 275 for Koa is perfect. use paper like everyone states. I put the package as follows from bottom to top. SS,Koa side, blanket, SS. I like to bend the waist to 85% then do the to bouts, after the bouts are done finish the waist he last 15%. whole process takes me about 5-6 minutes. be sure and thickness your sides properly. I use a Fox Style bender and an Lmi controller

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put the bindings in a pvc "3/4"" pipe with the end sealed-Add water & super soft fabric softener.
let soak overnight & It will
bend very easily -with heat.Not to much-I do not take any temps.
I do 5 pieces at a time.Just a tablespoon of the softener

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Mike Collins

Depending on the type of curl you have, if you soak curly koa, it will often basically desolve. Not a good thing! For backing I use 3 slats. 1 stainless on the bottom, wood wrapped in paper, a second stainless slat, the blanket, topped wih an aluminum flashing slat. The aluminum is there to prevent the cauls from damaging the blanket and makes the package easier to bend than using 3 stainless slats. My bender is hinged to open up to get better tail end bookmatches, so I start bending from the tail. Good luck! Would still like to see a photo of what you are working with. All curly koa is not equal as to how it bends.

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

I’m not much help when it comes to bending with a machine but I’ve bent many sets of Koa on a pipe with no problem and no staining.
It’s a good skill to have.
The only time I have ever had a problem is around the really tight bends On a cutaway usually get a couple of very hairline cracks that you fix with cyanoacrylate and you can’t see it.


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Blanket on top of steel slats (unless you want a pattern impressed on the wood).

I often glue a piece of paper to the outside surface of highly figured wood. It doesn't much matter what sort of paper or what glue you use. Paper is very strong stuff, and will help a lot to prevent the grain peeling loose on the outside surface of the bend. Only use water on the inside surface. When you're done just scrape the paper off.

I do a similar extra support sometimes with 4" wide blue tape on cutaways. It works great and can make a difficult bend possible. The heat makes the tape not that easy to ge off though. Paper sounds like a good idea. -Bob

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

Appreciate all the pointers. I'm going to attempt tomorrow. Here's what I'm working with.

Nice tip.

Nice koa. Looks very clear of knots or defects.That wood should bend fairly easily. It is the koa with the wider, deep looking curls that either kinks or breaks more easily. Should make a very nice guitar. Good luck, Bob

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

Thanks, Bob. I’ve got another set too that is a little wider like you mention. What do you think of this one?

Any tips on side thickness?

The second set should probably be easier to bend. Less curl and probably was a lot cheaper, so less pain if you break it. Depending on the flex of the wood, my sides are usually 2.3-2.5mm thick. Photo shows what i mean by wide, deep, curl. Lots of endgrain, which is what makes the bending risky.

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

That side thickness was for guitars. For ukes, like the one shown, side thickness is more like 1.7-1.8mm

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

Thanks!

This is what i meant by difficult to bend deeply flamed koa. Basically it is a lot of endgrain. It's been a few years and I can't remember. but I bet I had to use some stupid glue on the sides of the uke. The guitar I probably did O.K. on. Good luck with your wood!

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

That's some awful pretty Koa Bob. I have a nice set I got from you probably 10 years ago, I finally got the back joined so a guitar should pop out in another year or so - ha.

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Steve Smith
"Music is what feelings sound like"

Steve, I have a wee bit of nice koa left for myself, but it has been more than a year since I last saw anything nice for sale. it's out there, but smaller builders are not much in the loop anymore. I wonder what the next "koa" will be or have we pretty much burned through the best of the natural resources? Sell that koa set and buy yourself an electric car! Good luck and thanks for that purchase 10 years ago. I'm only still here doing this because a few people bought instruments and a few builders like you bought wood! BTW, I work on about the same time shedule as you these days. Eventually we get there.Good luck with your projects.

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso