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Well, it finally happened. On the 5th set of sides I’ve bent.....total fracture.
It’s mahogany at .085 thickness and bent dry at 290 - 310 degrees.
This has worked well in the past with only one small fracture in a koa side that filled and sanded nicely.
Looking at the normal culprits, thickness, temperature, and wet or dry.....to me this fracture looks more like the result of unfortunate grain orientation.
What are your thoughts?

Yes, the grain looks as though it is not aligned parallel to the length particularly well. I had a similar problem with some curly port orford cedar. It broke with remarkable ease, and at some of the breaks it looked as though the grain was almost perpendicular to the length because of the curl figure. Your side doesn't look quite that extreme, but the grain certainly looks as though it is angled enough to be a problem.

hand or bender?

I never had luck dry once the cell "set" you can't get the cells to collapse any further and this happens.

tippie53 wrote:hand or bender?

I never had luck dry once the cell "set" you can't get the cells to collapse any further and this happens.

I use my homemade bender.....see photo.....the caulk gun works surprisingly well at the waist

you need moisture
bending dry is not the best way.
What temps are you using?

tippie53 wrote:you need moisture
bending dry is not the best way.
What temps are you using?

My thermometer read 290-310 degrees during bending

sounds like to took too long
I bend at 250 for the lower the upper at 275 and them run the waist and take to 375 to set the heat.
You should be done bending in 4 to 5 min