Author Topic: Steam/heat treat  (Read 842 times)

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Offline DC

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Steam/heat treat
« on: July 03, 2018, 01:31:50 pm »
If you steam bend a heat treated bow does it undo the heat treat somewhat?

Offline Strichev

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Re: Steam/heat treat
« Reply #1 on: July 03, 2018, 02:00:43 pm »
I'm not sure how accurate, or factual this is but I remember reading that heat treating modifies hemicellulose (reduces the amount of free hydroxyl groups in it) and as such makes the affected wood have a lower equilibrium water content as it's then less hydrophilic.  I suppose that steam then wouldn't do any harm in that regard.




Offline simk

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Re: Steam/heat treat
« Reply #2 on: July 04, 2018, 01:12:58 am »
Concerning an actual project, i'm also interested in that topic. Myself I think, that probably steaming/bending an already heat treated piece of wood will not be as effective as steaming a non heat treated piece - the given and heat treated bend is already fixed by the first heat treating more or less. So i'm expecting less effect from the second steaming and a greater tendency to return in the former shape. Also a second heat treating will be necessary. Let's try! Just my 2 (theoretical) cents
--- the queen rules ----

Offline DC

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Re: Steam/heat treat
« Reply #3 on: July 04, 2018, 10:59:49 am »
That's part of the trouble I having with this bow. It had a long sideways bend that I straightened, then when I reflexed it I had to try to remember which way it was going to try to go back to. You have to restrain the thing to stop the sideways bend  from returning while you're trying to reflex it. Then if the string alignment is out(it was) you go through the whole thing again. I bet I have spent 10-12 hours steaming and heating this thing. It is by far the worst one I've dealt with but it's such a nice clean piece of wood. I straightened the limb again yesterday and it's sat overnight so i'll see if i can get it strung successfully today. I've almost given up twice.

Offline DC

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Re: Steam/heat treat
« Reply #4 on: July 04, 2018, 03:32:45 pm »
This ones going in the corner of shame. I strung it and the string was just a bit off center and as I watched it slowly started to creep over. Within two or three minutes the string was off the handle altogether. I might pull it out of the corner someday if I'm feeling masochistic. :)