Author Topic: bending oak ??  (Read 9934 times)

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Don Case

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Re: bending oak ??
« Reply #15 on: November 18, 2013, 06:36:19 pm »
I tried this kind of bend way back when I was trying to replicate a native bent cedar box. I put a "V" notch about 7/8 of the way through and boiled the wood. They all broke. I'm thinking that the bottom of the notch should be squared off some. That would give that sliver of wood room to bend. Just thinking out loud.
Don

Offline Tom Kurth

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Re: bending oak ??
« Reply #16 on: November 18, 2013, 10:02:02 pm »
I'm very much a novice where bowyery is concerned, but I am a long-time woodworker and cabinet-maker. From what I know of wood bending (not all that much really, but . . . ), I am surprised that that people have found a difference between sources of heat from species to species. My understanding of the mechanics of heat-bending is that the heat (from whatever source) causes the lignin to soften thus allowing the cellulose fibers to be rearranged. When the piece is cooled, the lignin re-hardens fixing the fibers as they have been re-configured. Thus, it seems to  me, the source of heat should only make a difference only insofar as one source penetrates the wood more or less effectively than another. Would appreciate any insights.

Best,
Tom
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Tom

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Offline steve b.

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Re: bending oak ??
« Reply #17 on: November 18, 2013, 11:42:51 pm »
I'm guessing you are right, Tom.  I think that the differences in source heating that you read about here are mostly individual experience and preference vs. what actually works or not with the different woods.

Offline swamp monkey

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Re: bending oak ??
« Reply #18 on: November 19, 2013, 11:20:07 am »
I cut a nice piece of quarter sawn red oak into sections so I could test bend them.  The first I applied dry heat.  I didn't do more than give the wood a slight tan but it was hot to the touch.  It did not even budge. 

I placed three other test pieces over a pot of water on the stove.  45 minutes over the steam.  Two of the three resulted in broken fibers on the side without the notch.  The other one did not bend nearly so much. 

I am thinking I need to tweak something. 

Offline PEARL DRUMS

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Re: bending oak ??
« Reply #19 on: November 19, 2013, 11:32:46 am »
Did you try to bend the dry heat test until it broke? Or did you just tunk it and it didn't budge? Id like to go home and try it myself to, but I have zero oak that isn't stained and going around the bottom our our walls!
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline Blaflair2

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Re: bending oak ??
« Reply #20 on: November 19, 2013, 12:18:29 pm »
If I was bending something like that I would round file the very bottom of the v slightly.

Since the steam tore out the belly then I'd try more dry heat.
Use crisco and get it all over. Heat about 4" from each side of the wood. Yes it'll be hot to the touch but u want the inside to get nice and warm. Think of it as a burger on the grill. U can get the outside almost burnt and the inside raw if not heated properly. If u have more oak then try the steam and the heat. Both with crisco.

Pot on the stove crisco the place h want to bend. Cover tight in tinfoil to trap the steam. I put the bow in when the water starts boiling.

But I think dons idea is key. U can't stess that little section so much. Also use a pressure strip to help hold fibers done
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Offline Onebowonder

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Re: bending oak ??
« Reply #21 on: November 19, 2013, 12:39:06 pm »
When we made canes with crooked tops in Scouts, we boiled the ends of each for what seemed like eternity, (...hey I was an 11 year old!), but we were able to bend those over like butter.  It was probably a couple of hours.  I remember that we had to feed the fire and add more water to the pots over and over again.  They were made of cheap oak trim boards, so maybe...

OneBow

Offline BowSlayer

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Re: bending oak ??
« Reply #22 on: November 19, 2013, 12:59:12 pm »
i recently did a oak recurve with steam, it was made from a board. i roughed it out and then steamed for 40 mins. bent nicely without lifting a splinter on the belly. the wood was 13mm thick
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Offline bubby

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Re: bending oak ??
« Reply #23 on: November 19, 2013, 07:27:25 pm »
I just did a test run with riftsawn red oak and a notch filed in it like the pic, steamed it for 30 min and didn't get much bend before it brock across the belly, and yeah pearl's I bent it till it broke clean off, I think that notch should be fairly deep, I don't know could a been a crappy pc of oak too
failure is an option, everyone fails, it's how you handle it that matters.
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Offline bubbles

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Re: bending oak ??
« Reply #24 on: November 19, 2013, 07:32:44 pm »
I put some serious hooks in a quarter sawn red oak board by boiling and bending with a metal strap. The strap made all the difference. Wood was .5" thick and .75" wide.  I took the form from a glass recurve. Both of the bows I did it on chrysalled horribly, but my recurve form and technique worked great! I think I boiled for 1/2 an hour.  I feel like you could get that bend without the notch, just use a strap on the belly. 

Offline bubby

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Re: bending oak ??
« Reply #25 on: November 19, 2013, 07:56:31 pm »
I did use the strap, I think the notch is the problem, it concentrates the bend in one specific spot
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Don Case

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Re: bending oak ??
« Reply #26 on: November 19, 2013, 08:06:57 pm »
Here's a link to how this one guy does bent cedar boxes. I'm not sure if this will work for you.
http://www.bentcedarbox.com/
Don

Offline swamp monkey

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Re: bending oak ??
« Reply #27 on: November 20, 2013, 10:08:44 am »
Pearl,  on the dry heat I couldn't get it to bend.  So i couldn't bend it until it broke unless I Hulked out  >:D

blaflair2,  I like the idea of rounding out the V bottom.  I will have to check my pics of authentic Eskimo bows but there may have been a slight gap in that location. Your method would explain that nicely.

Bubby,  Did you use tin foil?  I confess for my tests I did not.  How does this tin foil contraption work?

Offline bubby

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Re: bending oak ??
« Reply #28 on: November 20, 2013, 02:51:43 pm »
I just used the foil to cover it, ya know a couple of issues back Mark St Louis had an article combining steam and a heat gun perhaps that would work for you
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline PEARL DRUMS

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Re: bending oak ??
« Reply #29 on: November 20, 2013, 03:25:59 pm »
Ive done that bub, it worked when nothing else did on a lateral move with yew. Take a square of cotton t-shirt and get it wet through. Wrap it around your bend area and then cover that with aluminum foil and seal it the best you can. Then heat her up! Its a gentle steam I guess and it works.
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.