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Okay so I put a wenge rib into my fox style blanket bender .09" thick started the bend at 220F with light water ended the bend at 320F. I let it sit till it cooled and then cycled the heat two more times. When I took it out of the bender I had a lot of spring back and I noticed one small crack at one end. I took it to the hot pipe to finish setting the bend and cracks started opening up all over.
Am I using too much heat/ water/ pressure? It doesn't want to take a bend. I have only bent maple and mahogany before. Is this typical for wenge? I have a lot more wood, so I need to figure out how to bend it without it all cracking up. Any advice?

I've only bent one set of wenge rims on a bulb bender. I spritzed with water and started the bend at around 300F, took it up to 320F like you and cycled the heat once. They were thicknessed to 2.0mm

Spring back was minimal, but I did get a small amount of cupping in the waist area, so I imagine I could have gotten by with even less water.

Other than the cupping the bend went OK, although I did end up with a split when I bumped the side in the mold

You may be starting the bend too soon, but then using a blanket might be a bit different than bulbs. I'm sure someone with more experience with wenge will chime in soon.

Cal

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Remember, there are no stupid questions, only stupid answers!

Thin to .080". .090" is about 40% stiffer. Wenge loves to split, when it isn't busy spitting splinters at you. But it bends OK.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Whilst I haven't bent Wenge, I have recently and successfully bent it's equally EVIL splintery/cracking step-sister Padauk. (.080")

I wrapped the side in kraft paper dampened the paper and wrapped it in foil. Placed it in the Fox style bender (with blanket) let the temp go to 300 for a few minutes then started to bend. Lower bout first, then upper bout, finishing with the waist last. The waist part was bent painstakingly slow and don't crush the final turn tight against the form just nice and snug. Let cook for 8-10minutes and unplug and let cool. Give it another cook cycle and let cool again (overnight worked for me). Place in form crack and splinter free.

It is not the quickest process in the world but it beats the alternative...Firewood!

PS The kraft paper has an added benefit of soaking up a lot of oils that you won't have to sand later...

Ray



It was the first time I did the paper foil thing but it worked great.

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Guitar Building = Continuous Improvement Process

I bent my last by hand. Thicknessed to about .075 - .080. Didn't find it particularly difficult, asides from the splitting, spitting and crater-like pores...

Pore filled with Pumice which worked like a charm. Although I found Wenge to be usually boring to look at, it came alive under finish and is now fantastic!

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Thanks for the tips.
I tried the other side last night and it turned out fine. I used more water and more heat. This time there are no cracks at all. It did turn a funny color though. I wonder if it reacted with the aluminum foil. I resawed both sides for the same board. The first one was from the outer face of the board. It had all sorts of really dark oxidation that i barely sanded through during thicknessing. I'm guessing that that had something to do with it's brittleness. I got 5 slices form that board, so I'll just bend another one. I think I'll go thinner next time too.
Thanks again
Andy

Andy, Wenge is also pretty oily. That dark oxidation might be cooked oil.

Also, I've heard of some woods (like Koa) that don't like the aluminium foil at all, however, Wenge is dark enough that I don't think it would matter much, but, to be on the safe side, you might want to try using craft paper instead.

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I'd like to be able to prove, just for once, that money wouldn't make me happy...