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I keep breaking these things and it's driving me nuts. My first guitar didn't give nearly this much trouble and it was a tighter bend on an iron with off quarter maple. These I'm doing on my newly finished fox-style bender with heating blanket. Here's my method. I spritz the sides with water then make the sandwich (top to bottom) : slat, blanket, foil, side (.080), foil, slat. I wait till the temp is 280 F then crank the waist down till about 1/2" from the form then do the lower bout then do the cutaway then go back and do the rest of the waist moving pretty briskly as per John Hall's youtube video. Even though I'm new to the bending machine I still get this all done in under 5-6 minutes. The last set I let sit in the machine over night and this is what I keep ending up with. Any thoughts, suggestions?
Jason

I'd say its too thick and too fast. What's the hurry to get it bent in 5 minutes? Maybe thin the cutaway area down to 0.07". Even bendable wood doesn't bend that fast. Maybe slow down next time and let it relax

I bend maple dry / no spritz of water

I would take that to about 75, and it should bend well .. light spritz, not wet ... and I bend fast as well, there is really nothing to wait for once the wood hits temp - but it must be supported, and even under some tension when bending ... my slats in the upper bout are both spring loaded (inner and outer) for venetian bends, as the first bend is outside, the second inside.

we bent exactly that shape last night in EI rw, heat for 2 minutes, bent in 3 .. beautiful.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

I've bent numerous curly maple cutaway sides. For the cutaway, sand that area to .0625 to .070. I spritz with filtered water. I have tried super soft on maple and find that it leaves permanent stains. For me, I spend about 5 minutes total to bend one side for flamedd maple. Just a little turn at a time - and hold your breath!

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John Ressler

Thanks guys. I'll try pulling up a bit more on the cutaway end while I crank the ram down. I'll see if that doesn't put a bit more tension on the back side.
Jason

Further to what Tony said regarding support: I would recommend putting the blanket on top of the slat, i.e. so that the slat is closer to the wood instead of the blanket as compared to your arrangement. I also am a believer in using spring steel as opposed to stainless steel just for the additional support.

Pat

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There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

As Pat just said. Your blanket is in the wrong place in the stack. I always keep a slat on both sides of the wood for support then the blanket.

I think you can try the thinnig. Maple does like heat so try it about 350. Once bent lower the temp to 250 and let cool

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Still no luck. The last set I just broke was .065. I'm at a loss. The last few attempts were with the thinner sides at a higher temp with the blanket on top. Anyone want to come over and show a fella how to do this?

call me

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Those outer fibers must be supported by a very tight slat on the outside of the bend.
Some flamed maple will bend just fine and the next set will not.
What is the inside radius on your caul and the mold, Jason, it looks fairly tight.
Nelson

Have you got a portable steamer?

Steam the area after you have preheated and then try bending. It should make the fiber relax and bend like butter.

Kevin Waldron

Thank you all for your help. I would like to thank John Hall especially for talking me (down off the ledge) through some of my mistakes. Nelson the radius of my cutaway is about 2" or so. I did finally get some sides to cooperate and now there is once again peace in my shop. Thanks again. You guys/gals are all aces.
Jason

Glad to help ,that is what we like to do.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Jason, I'm glad you got your problem solved. This thread has a lot of tips, but you don't mention how you solved the problem. It sounds like there was some key info in a phone call between you and John. For the rest of us who followed the thread with interest, would you and/or John let us know what seemed to make the difference?

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Tim Allen
"Never hurry, never rest."

What Tim said.

Jason, do you mean 2" radius or 2" diameter of the cutaway?
Looks more like a 2" diameter or 1" radius.
Nelson

Sorry about that. I was basically letting the wood case harden. I was waiting too long to start bending and letting all the moisture cook off before I got the wood fully bent. John told me to start bending sooner and to take a wet paper towel or craft paper and wrap the cutaway area to make sure that area had moisture. So far so good. I've managed to successfully bend a couple of cutaway sides without anything but happiness. Yes, 2" diameter. Oh, and another thing I've done was to just take a cabinet scraper to the cutaway and bring it down into the neighborhood of .065-.070. Nelson, I'm curious how you go about it since I doubt you're a stranger to bending maple.
Jason

Jason, glad to hear of your success. I think John is spot on in and I agree that the timing of the bend process is really important.
I used a Fox bender for several years prior to acquiring the Better Way Bender prototype from Brad Way several months back.
It uses the air cylinder tensioned band method of maintaining heavy band pressure against the outside of the bend.
Best regards
Nelson