Author Topic: Steaming  (Read 944 times)

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Offline BowEd

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Re: Steaming
« Reply #15 on: June 22, 2018, 06:28:55 am »
Yes I do what you'd call a full heat treatment clamped onto original form.Holding heat gun 3 to 4 inches away until browned well on hickory recurves.That'll run temps up to well over 350 degrees F.I don't have any here that'll pull out then.Even from extreme reflex.
BowEd
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Ed

Offline DC

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Re: Steaming
« Reply #16 on: June 22, 2018, 06:51:48 am »
DC I have the same basic set up as you and with the bag it bends very fast, 10-15 mins
What thickness are you bending in 15 min?
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Offline bubby

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Re: Steaming
« Reply #17 on: June 22, 2018, 07:05:06 am »
DC I have the same basic set up as you and with the bag it bends very fast, 10-15 mins
What thickness are you bending in 15 min?

Half an inch or so
failure is an option, everyone fails, it's how you handle it that matters.
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Offline DC

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Re: Steaming
« Reply #18 on: June 22, 2018, 07:30:26 am »
I've done some testing where I rifle drill a piece and put a thermometer in the hole and then steam the piece. I used about 1" dia pieces and although I can't remember how long it took it was kind of an exponential curve. The first half heated up pretty quick but the last little bit never did get over 200 degrees.  I did keep records but I have no idea where I put them :o :o 
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Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Steaming
« Reply #19 on: June 22, 2018, 08:38:31 am »
100 Degrees C (212F) will soften for bending.
300 C (~570F ) will heat treat and fix a bend in place.
Del
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Offline DC

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Re: Steaming
« Reply #20 on: June 22, 2018, 10:07:00 am »
My wood starts to turn brown at 400f. 570 would be black. Does that agree with your thermometer?
Vancouver Island
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Offline leonwood

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Re: Steaming
« Reply #21 on: June 22, 2018, 11:13:52 am »
For sideways corrections I have the most success with dry heat so now that is al I use for corrections, for recurves I always boil or steam (in a pot, covered with alu foil). Since I started “setting” my boiled recurves with dry heat I have never had one come out.

CrescentWalk

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Re: Steaming
« Reply #22 on: June 22, 2018, 12:26:00 pm »
Dry heat work's well in my experience but take's experience and patience to avoid overbending leading to a tension break and/or to avoid scorching the wood. Multiple re heat's might be necessary. My theory is that dry heat will temper the bend into the bow so that it is unlikely to pull out. The best thing is that no heat gun's are necessary, it can easily be done over a small fire. Best of luck.

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Steaming
« Reply #23 on: June 22, 2018, 12:43:11 pm »
My wood starts to turn brown at 400f. 570 would be black. Does that agree with your thermometer?
I'm just giving rough figures from a test I did ages ago... I think I was going on the heat gut setting not the actual wood temperature.
BTW, the fancy heatgun with the build in digital temerature readout didn't last long before the fan melted. The cheapo ones work just as well ::)
Del
Health warning, these posts may contain traces of nut.

Offline DC

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Re: Steaming
« Reply #24 on: June 22, 2018, 12:48:32 pm »
The best thing is that no heat gun's are necessary, it can easily be done over a small fire. Best of luck.
Try holding this over a small fire. Weighs about fifty pounds ;D ;D ;D
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Offline DC

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Re: Steaming
« Reply #25 on: June 23, 2018, 08:38:25 am »
I think this one's defeated me. This is the fourth time steaming and this time I followed up with a heat treat to just before browning then left it clamped to the caul overnight. It came out of the caul pretty straight and fifteen minutes later it looks like this.
Vancouver Island
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Offline Pat B

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Re: Steaming
« Reply #26 on: June 23, 2018, 05:04:38 pm »
DC, put it on your form and use a heat  gun(I like to oil the belly and sides before heating) and use clamps and wedges and you should be able to straighten that out.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC