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I just broke my first side. I did some test pieces of Indian rosewood And that went well. Even did a cutaway on my bending machine. Then Went to do the black acacia on the non cutaway side and it broke on the upper bout. I'm using slat wood slat blanket on top. Heated to 330 started bending the waist then the lower bout the upper and I felt it and heard it snap right in the middle of the bend. I did pre taper the side and I never did on the test pieces I bent. I don't know if that has anything to do with it. I think I bent to fast but idk. Side was .80 thick and I hand planed for thicknessing so it varied from .75 to .85 is that ok? I think I just put to much pressure on it. I was going to try a cutaway but now I'm rethinking that when I get my new sides.

Unfortunately that happens sometimes. Your temp/setup/thickness seems to be fine. Could be you went a little too fast, could be the wood. Some wood just won't. We've taken to using super soft 2 veneer softener on every single piece, even if it should be an easy bend like walnut or rosewood. And still have a snappage from time to time.

If you started at 330 to bend the waist, then lower, then upper bout, it's possible the upper bout was completely dry by the time you bent it.
I usually start at 230/250 for the waist, move quickly to the lower and then upper bouts.

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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.

my thought as well, maybe you cooked the wood hard. I am finishing my bend around the time the wood hits 300. I start around 275.

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I thought that was maybe the problem too but I just tried to bend the other side that had a cutaway. Did the same thing. Has a 1in crack in the cutaway area. I was done bending in 3 min and started at 275. Should I get super soft and try again on a new set? I'm not soaking them just misting with water

Is there anyway to fix cracks? Or am I better off getting new ones?

send a pic.
Mike

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Mike Collins

Very hard to fix cross grain snapped sides invisibly, pretty much impossible...

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How thick are your bending slats?

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Jim Watts
http://jameswattsguitars.com

I'm using .008 steel from lmi

my slats are .024 springy stainless, I don't remember the alloy, but I,m certain they support the bend better. I've never broken a side using the bender. I use to just heat with light bulbs too, I use a blanket now.

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Jim Watts
http://jameswattsguitars.com

I broke several sides until I changed my bending order. I start by bending the waist just a bit, then the bouts, then finish bending the waist.

Did you use moist brown wrapping paper on either side of the side. That and as mentioned, bending the waist halfway, then the lower and and upper bout and clamping them snug and then completing the waist helps.
I went to two blankets about 10 years ago and that has seemed to be a good thing.

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I believe the thinner steel slats won't support the bend as well as the thicker slats.

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Jim Watts
http://jameswattsguitars.com

Have never bent black acacia, but have made about 13 guitars, each with a different wood. My slats are also spring steel and about 0.024 inches thick as well. I use (from bottom to top) a slat, aluminum foil, wet craft paper, wood, wet craft paper, aluminum foil, heating blanket, slat sandwich when I bend. Start around 270 degrees when I begin to see steam and my bend is done in just a few minutes. I bend the waist about halfway, bend upper bout, lower bout and finish the waste. Haven't had a problem yet, but not all that much experience. I do have some super soft, but have only used it once. Your thickness is similar to mine; I routinely try to get about 0.08 inches regardless of the wood species. I do like the support of the spring steel, and I like to see steam coming off as I bend so that I know the wood is not too dry (did cook a piece of lacewood once, but it bent fine). Could be as meddlingfool (Ed) said, just a bad piece of wood, but it's worth reviewing your process.

I got new sides on the way. I'll try it again. I wanted to do a cutaway I have tried 4 times with practice sides and only been successfull 1 time. So if I do try a cutaway I think I'm doing it on my pipe by hand.

More water won't hurt as long as you let it "cook" for 15-20 min after the bend is complete. 290 degrees though otherwise you'll scorch the wood. Avoid aluminum when working black acacia or koa!!! Use distilled water also.

I've done 3 of 13 guitars from black acacia, no issues here. Follow the advice regarding the bend procedure (waste half way, lower then upper bout, finish the waste) and you should be good to go.


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"There's really no wrong way, as long as the results are what's desired." Charles Fox

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Super Soft II, It's almost like cheating. . .

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