I mostly use vertical bamboo flooring for my lamination on my fiberglass bows. I've been reading on how tempering the bamboo increases performance. My question is what method works best for tempering bamboo laminations?

Wonder how the glue joints would hold up?

I don't believe you can temper laminated bamboo; all you can do is color it with heat -- not the same thing.  The glues may fail, but I suspect that their strength will override any attempt to strength-temp the natural material.

You can buy caramelized laminated bamboo. I think it is caramelized at the same time it is laminated. Trying to do it afterwards might compromise the glue.

http://www.powerfibers.com/BAMBOO_IN_THE_LABORATORY.pdf

I wasn't talking about tempering laminated bamboo but tempering regular bamboo. I guess my question was unclear.

I temper bamboo for the belly lams of tri-lam bows. This is bamboo with the outer rind still on. Flatten the slat, then use a torch or a heat gun to blacken the rind. Let it cool a few minutes, then continue to flatten it. The heating will cause the slat to cup backwards. This will allow you to really get it flat.
Once you're done getting it flat and tapered, you need to glue up your bow or the tempered lam will cup again.
In my opinion you shouldn't temper the core or the back lams. Bows I've built with tempered backs blew up sooner or later.
Dave.

Quote from: hunting badger on January 03, 2021, 12:09:16 AM
I wasn't talking about tempering laminated bamboo but tempering regular bamboo. I guess my question was unclear.

Did you read the info in the link?
Somebody did a lot of experimentation to acquire and document the information you are looking for.

What woodcarver said.

Yo guys, he's making fiberglass laminated bows. No rind, no outer power fibers involved after milling.

That's what I get for reading too fast.
Correct me if I'm wrong, but in a glass bow there's no need to temper the core lams.
Dave.

Quote from: hunting badger on January 03, 2021, 12:09:16 AM
I wasn't talking about tempering laminated bamboo but tempering regular bamboo. I guess my question was unclear.

I think there is no reason to temper the core unless you wanted to change the color. The reason the belly is tempered, for boo or other belly woods is to help with the compression strength, many belly woods don't need this help.

 Did you guy's read the link with the extensive test data this guy accumulated? No need to speculate, there is a crapload of data for anyone with the attention span to read all the technical info laid out in it.
Heat treating Bamboo or wood will increase its modulus of elasticity, up to a point.
I do agree that it is likely not worth the effort on a milled piece of Bamboo, owing to the fact that the outermost power fibers (most desirable) have been milled away. Still it's documented that there is a small MOE gain even when using the more pithy part of the culm. All that said, it's probably worth doing if you accept the small gains in performance, you like the pretty caramelized look and get enjoyment from experimenting.