Author Topic: Taking a twist out of Elm stave with a heat gun??  (Read 1218 times)

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Offline SpringyWoodPassion

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Taking a twist out of Elm stave with a heat gun??
« on: January 18, 2023, 09:37:41 am »
Hi everyone!
I have had issues using a heat gun when trying to recurve limbs in Elm. Elm did not take it too well as it developed cracks on the belly.
Now I have an ugly twist at upper 1/3rd of the limb.  I really like this stave and I don't want to screw it up with a heat gun again.
The twist is not extreme, but it will affect proper alignment of the bow.
Any ideas what I should use to take the twist out, apart from the dry heat.
Perhaps I should pour boiling water where the twist is before applying the heat gun to it. I don't know.   ???
I've tried steam bending my Elm staves before, but the limbs always returned to their original shape, so I was not super happy with steam bending elm.
Any ideas what I should do would be much appreciated!
Thank you in advance

Offline Pat B

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #1 on: January 18, 2023, 09:54:35 am »
I learned the hard way that when adding recurves, steam or boiling is the way to go. I built 2 elm recurves and added recurves with dry heat and both cracked. I repaired them by adding underlays but any other recurves I do will be with wet heat.
 Is the twist in the limb natural(was it always there) or is it only when the bow is braced? If the twist is natural you can put the stave on a caul and with dry heat(I use oil here too), clamps and wedges you can get the twists out. At the same time you can add reflex and temper the belly.
 If the bow twists only when braced check the limb thickness from side to side. Uneven thickness causes twists.
 When you steam or boil for recurves leave them in the bending caul, let it dry well and use the heat gun to temper and set the recurves. This will help prevent them from pulling out.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline SpringyWoodPassion

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #2 on: January 18, 2023, 11:00:01 am »
Thanks a lot.
And yeah, the twist is natural.
So you're suggesting that I can go ahead with the heat gun on the clamped stave, but putting some oil beforehand, am I right?
Thanks again

Offline Pat B

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #3 on: January 18, 2023, 11:40:34 am »
If you are putting it on a form that will introduce reflex then you don't have to use oil but you will need to counteract the twist by strategically placing wedges to "untwist" the twist. You can also temper(heat treat) the belly which will also set the corrections. This can also be done over if the twists don't come all the way out.  If you are only removing the twist you can also do this by clamping the twisted limb and use a wrench and weights to correct the twist as you heat. Eric Krewson has pics someone here that shows how he does it. Anytime I'm not tempering the belly I use oil with dry heat.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline SpringyWoodPassion

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #4 on: January 18, 2023, 12:07:31 pm »
Ok.
How about pouring boiling water on the twist and then clamping it?

Offline Pat B

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #5 on: January 18, 2023, 12:14:20 pm »
The heat from the boiling water just poured over it won't penetrate enough to matter. If you steam it for 15 minutes to a half hour the heat will get down into the wood. For adjustments like you want to do I use dry heat with oil unless I'm also tempering the belly.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline SpringyWoodPassion

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #6 on: January 18, 2023, 12:37:17 pm »
And when you're tempering the belly you don't use oil? Just the heat gun?

Offline George Tsoukalas

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #7 on: January 18, 2023, 12:38:32 pm »
I don't do recurves or forms. I read this method somewhere. It works  for straight limbs.

http://traditionalarchery101.com/fixtwist.html

Jawge
Set Happens!
If you ain't breakin' you ain't makin!

Offline George Tsoukalas

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #8 on: January 18, 2023, 12:41:15 pm »
I apply oil to the belly only. I am of Greek ancestry so I use olive oil. :)

Make sure the wood is dry or it will check...not that you think it's dry but dry.

I use a moisture meter through the bow making process.

Jawge
Set Happens!
If you ain't breakin' you ain't makin!

Offline Pat B

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #9 on: January 18, 2023, 02:06:13 pm »
No oil when tempering, only dry heat and enough to scorch the belly wood. You never want to scorch the back.
Here is how I do it. There are pics in my "New Bow Started" thread on pg 4 or 5 I think.

 "Yeah, at least the way I do it. Elm doesn't seem to darken much doing it this way.
I hand hold the heat gun about 1" above the belly and move it back and forth over a 6" area. When it darkens I move out to the next 6" heating until it darkens but also go back over the previous 6" then on out the limb and keep coming back over the previous heated sections. I do this with the limb held in reflex."
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline SpringyWoodPassion

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #10 on: January 18, 2023, 02:33:59 pm »
Thanks Pat.
So the belly of the elm doesn't crack on you even when it darkens?
Also, in your first post of this thread today you mentioned that you prefer steaming or boiling Elm over dry heating.
So when do you steam and when dry heat Elm. In which cases do you prefer one method over another?
Thanks

Offline Pat B

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #11 on: January 18, 2023, 04:08:18 pm »
Wet heat for recurves, steam or boiling. Dry heat for reflexing, corrections and tempering. Oil with dry heat for reflexing and corrections but not for tempering.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline SpringyWoodPassion

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Re: Taking a twist out of Elm stave with a heat gun??
« Reply #12 on: January 19, 2023, 05:38:31 am »
Gotcha.
I will certainly follow your suggestions.
You've been a great help. Thanks a bunch Pat!

Also, some guys like to use heat gun right after steam bending. Is that a good idea or is it just overkill?
Thanks