Steam and heat treating

[DC]

I'm working on a Plum bow that's giving me a bit of trouble with string alignment. I've heat treated it once or twice. In order to correct the alignment I wanted to bend it just out of the fades where it's a bit too thick to use dry heat so I steamed it. Let it sit for a day and when I put it back on the tree it had a hinge where I'd steamed it. The first time it happened I though I'd accidentally put a little deflex in while steaming it. Never though much about it, corrected it with dry heat and went on my way. Then I did the other limb, same thing happened. I've never noticed this before. It looks like the steaming sort of undoes the heat treat. Is it possible it's just Plum? Anyone else notice this?

[Gordon]

My experience is that steaming will undo any previous heat induced adjustments.

[DC]

It didn't just move, it actually lost any stiffness that the dry heat had added. The steamed section went limp. If I had removed any wood I would blame myself but all I did was steam it, move it sideways and now I've got a weak spot. I just finished re heat treating that spot so we'll see tomorrow.

[Gordon]

Again my experience is that it takes a couple of days of drying before it is safe to bend an area that has been steam bent.

[PatM]

While steaming does relatively dry wood  the outer portions are still generally damper after steaming.   Let it dry for a few days while still clamped and then hit it with dry heat again in the correct position, just like you would with recurves.

[mmattockx]

In order to correct the alignment I wanted to bend it just out of the fades where it's a bit too thick to use dry heat so I steamed it. Let it sit for a day and when I put it back on the tree it had a hinge where I'd steamed it.

I have been doing bending tests of various pieces, boiling them for the heat source. One day has not been near enough for them to fully dry after being bent and I live in central Alberta, which is a desert compared to Vancouver Island. I'd give it a day on the form drying, hit it with heat to set it and then let it sit 2-3 days at least to be sure it wasn't still soggy enough to affect strength.


Mark

[Santanasaur]

I've had the same experience as Gordon. A few times I've steamed hickory recurves that were originally set with dry heat, and they pulled out most of the way back to the original position. Same for tip alignment corrections with hop hornbeam, always wanting to go back to the original shape. That stuff has memory like an elephant

[DC]

Impatience biting me again