Author Topic: Steam bending apparatus  (Read 790 times)

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Offline Bruce M

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Steam bending apparatus
« on: March 04, 2024, 09:12:16 pm »
I have been steam bending using a roasting pan on top of my coal stove, the stove will be cut off in coming month or so and I want to continue learning how to make these bows in the warmer months.

I bought a wallpaper steamer 15 or so years ago and it's works perfectly. I have on hand some of the green 6" drainage PVC and also some 3" electrical PVC but it's not as thick walled as the drainage pipe is, I think that would probably not withstand the heat.

I'm curious what the benefits, or detractions there would be for making the hot box full length of the bow vs making it 1/2 length and would there be any issues with steaming the handle. Also if anyone has better materials or designs of a hot box I'd be all ears.

thanks.

Offline Muskyman

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Re: Steam bending apparatus
« Reply #1 on: March 04, 2024, 09:39:21 pm »
I use a 4 inch aluminum downspout with my steamer and do 1/2 of the bow at a time. I donít do the handle if itís glued on. I do 1/2 at a time so Iím not rushed. I also pre-plan every bend. If Iím straightening in the handle area only I have a shorter piece of downspout Iíll plug the ends with rags. I also put holes in the bottom of my downspout to let water escape. I steam the handle area for about an hour and limbís for about 45 minutes.

Offline superdav95

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Re: Steam bending apparatus
« Reply #2 on: March 05, 2024, 10:33:49 am »
Ya I do much like MuskyMan.   I just used a old 4-5í long section of 4Ē diameter abs pipe plugged at one end with rags like mike said.  Steam is great as it cannot overheat your bow wood.  It gets to a set temp and does not accumulate heat.  Itís the safest way to bend and make corrections.  For tips with more recurve Iíll use a steel strip backing incorporated into my bending set up to prevent lifts of grain.  This can mostly be avoided if belly has been left to a single growth ring. 
Sticks and stones and other poky stabby things.

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Offline Bruce M

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Re: Steam bending apparatus
« Reply #3 on: March 05, 2024, 01:28:55 pm »
Thank you both for that information. I really like the downspout idea, I have some of that styro-insulation board that I can wrap the downspout in to keep the heat a little better.
I was thinking of some sort of flat steel that I can bend to a recurve shape just for that reason you describe, I tried a recurve but it failed miserably.
I am using shellbark hickory for now until I can get more consistent/predictable with my builds, Thanks again guys.

Offline Muskyman

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Re: Steam bending apparatus
« Reply #4 on: March 05, 2024, 06:33:10 pm »
Donít have to worry about keeping the heat in Bruce  in a couple minutes after putting the hose from your steamer in the downspout it really hot to the touch. I just plug the ends up and let it steam for about 45 minutes. Just have to figure out where youíre going to bend it prior to taking it out and go to work after you take it out   Videos all over the place online if youíre inclined to watch them. I was amazed at what I did when I got my steamer. Never had much luck with the heat gun myself. Always over or under heating everything. Some on here are magical with it but not me.

Offline Bruce M

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Re: Steam bending apparatus
« Reply #5 on: March 05, 2024, 09:19:29 pm »
Sounds good, just keep it simple, I'm going to go that route.
I have the form all set although after reading the "show your form" thread I think I might add a backer board like some of those pictured in that thread, this way I can clamp some curve out of the limb if needed.

Offline Bruce M

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Re: Steam bending apparatus
« Reply #6 on: March 08, 2024, 02:42:55 pm »
I went out to my scrap yard and found a 7" SS chimney liner, plugged it with some conduit plugs and slit some holes where needed. Worked incredibly well, thanks for the better ideas.



I did the left side yesterday and the right side this morn.

Question about heat treating that I'm a little confused with and that is when should I heat treat. Should I get it more closer to final thickness, it's getting close to that, probably an 1/8"-3/16". Seems to me anyway that maybe I should heat treat it now while clamped in the form to try and set it in place.
I'll be using a heat gun for that purpose, or is heat treating once it's been steam bent not necessary, I just dunno.

Offline superdav95

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Re: Steam bending apparatus
« Reply #7 on: March 09, 2024, 10:24:15 am »
I went out to my scrap yard and found a 7" SS chimney liner, plugged it with some conduit plugs and slit some holes where needed. Worked incredibly well, thanks for the better ideas.



I did the left side yesterday and the right side this morn.

Question about heat treating that I'm a little confused with and that is when should I heat treat. Should I get it more closer to final thickness, it's getting close to that, probably an 1/8"-3/16". Seems to me anyway that maybe I should heat treat it now while clamped in the form to try and set it in place.
I'll be using a heat gun for that purpose, or is heat treating once it's been steam bent not necessary, I just dunno.

Bruce.  I would get your steam bending or corrections done and then let it sit for a few days.  I would get it floor tillered stage then heat treat.  If you use a heat gun for heat treatment just clamp bow to your form and move heat gun along and inch or two every 3-4 mins.  Depending on heat gun and settings heat output.  This is for white wood only btw.  Donít do this with Osage or yew/junipers.  You can add rails to the sides of your form to rest you heat gun holder onto to maintain equal distance while moving along.  The other option is to incorporate a couple straps to do the same thing.  Iíll include a picture of mine.  The other thing to consider is to place a layer of insulation wrap between your bow back and your form to prevent the heat wrapping around to your back and scorching it.  You should end up with a deep penetration midway through the limbs thickness leaving visible browning but not scorch black.  Last pic shows the deep penetration of heat midway.   Hope this helps. 
« Last Edit: March 09, 2024, 10:36:23 am by superdav95 »
Sticks and stones and other poky stabby things.

superdav95@gmail.com

Offline Bruce M

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Re: Steam bending apparatus
« Reply #8 on: March 09, 2024, 11:40:22 am »
Yes it is very helpful and pictures are always appreciated, I'm more of a visual person.
I will get it a bit closer to final thickness and more bendy before heat treating, I think maybe getting it to brace might be a good point to heat treat, I'll try that and see how it goes.
Thanks again for the help.

on edit; Didn't mean to gloss over probably the most important advise in your response and that is to let it sit for few days before doing anything.
I tend to try and push things along at my pace but I'm quickly learning that doesn't usually work in doing this sort of thing, I will let it sit in that form at least 3 days.
« Last Edit: March 09, 2024, 11:48:29 am by Bruce M »