Author Topic: When to heat treat?  (Read 5211 times)

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Offline Weylin

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When to heat treat?
« on: May 27, 2009, 12:24:18 am »
I have a hickory self bow that has taken a fair amount of set. I am still tillering the bow and I have not yet gotten it down to the target weight. My intention is to heat temper the belly with a heat gun while weighing down the tips to hopefully eliminate some of the set and to strengthen the bow against further set. I have the TBB4 heat treating article as a guide. My main question is at what point in the process is it best for me to temper the bow. Should I do it now before I have my limbs evened out and tillered or should I wait until they are as good as they are going to get? will taking off wood to change the tiller and weight after the tempering process effect the results of the heating?  What about bringing it to target weight, should that happen before or after the tempering? I know that the tempering will most likely increase the draw weight. Here is a current picture of my tiller to help give some prespective.



Thanks in advance for your advice.  8)

Offline Bowmonk

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Re: When to heat treat?
« Reply #1 on: May 27, 2009, 02:19:26 am »
A fair amount of set... 

Lose the tillering stick and get you a pulley system...  even the amount of time you had the string drawn back on the stick to take a photo is detrimental to wood compression. Especially if your limbs are still thick.

I recommend at this point hitting your target weight + 5 lbs. Concentrating foremost on getting your tiller balanced. Once it looks good for spot tiller sand it with some 100 grit paper (this will leave a smooth and even surface that is less likely to scorch when applying heat).

Get a 2x4 that is bow length or little longer, then reflex your bow over a 3" to 4" block, and tie the bow tips down to the 2x4. Apply grease, lard, olive oil and heat with a heat gun, constantly moving as not to scorch or overheat in spots. You want the heat to be the same throughout the full length of the bow.

Leave it tied until it cools to room temperature, and reach your target weight with sanding, or light scraping if the tiller has changed a little after the heat treating.

Hickory is a humidity sponge, so i recommend sealing the wood as soon as possible after you have shot it in several times.

Russ

Offline Pappy

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Re: When to heat treat?
« Reply #2 on: May 27, 2009, 05:19:17 am »
I do about like Bowmonk,heat treating will add a few pounds so you can fine tune the tiller
after the heat treating.Also I only use the tiller stick till I get it to brace.Then I go to pully
system. :)
   Pappy
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Offline Hillbilly

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Re: When to heat treat?
« Reply #3 on: May 27, 2009, 07:13:47 am »
If I'm gonna heat-treat a stave, I also do like Bowmonk and Pappy said-I get the limbs bending evenly as I can to about brace height or a little less, then clamp it down and heat it. I think that it's better to prevent set than to try to cure it. Once the belly cells are crushed, they ain't pumping back up. Heat treating in the later stages of tillering will help some, but I seem to have gotten the most benefit from it myself by doing it early. I also agree about the tiller stick- a pulley system is much safer for you and the bow both.
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Offline Weylin

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Re: When to heat treat?
« Reply #4 on: May 27, 2009, 11:13:56 am »
Thanks alot for the advice guys. The 2X4 and block idea is good. I wasnt sure what to put the bow on top of for the tempering. I would love to have a pulley system but I haven't figured out a way to do make one in the apartment that I live in. If you have any ideas about a building a pulley system in an apartment I'd love to hear it. I have a small patio and patch of grass but nothing to bolt the stand to.


Offline smokeu

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Re: When to heat treat?
« Reply #5 on: May 27, 2009, 02:42:58 pm »
I used a tree... cost about 5 dollars. looks like crap but functions. 8)
Longview, TEXAS

Offline Bowmonk

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Re: When to heat treat?
« Reply #6 on: May 27, 2009, 04:25:03 pm »
I do agree with hillbilly about heat treating sooner to "prevent" set... but in this case i only recommended doing it after the +5 lbs to target weight, because the set damage has already been done in the belly being overly compressed.  Better to try and reach the tiller and weight target at this time or there is a chance of hardening the weak spots and snapping them , whereas they are a little more forgiving right now do to the softness and flexibility.

Russ

Offline NOMADIC PIRATE

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Re: When to heat treat?
« Reply #7 on: May 27, 2009, 05:01:56 pm »
I temper my bows first time at very low brace when tiller is even, once again at 20", and last 1" before final draw.

...I wouln't pull that bow that far with such an uneven tiller,...and yeah tillering sticks aren't the best thing,..no room for a tree ?  a mirror or big window will do just as good.


....And I wouln't bother on this one to temper reflex on, too late damage is done,..... maybe just temper it straight,...good luck
NORTH SHORE, HAWAII

Offline Dano

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Re: When to heat treat?
« Reply #8 on: May 27, 2009, 05:09:22 pm »
Here's some plans for a tree, you can strap this to a tree, lamp post, or whatever.

"If the women don't find you handsome, they should at least find you handy."


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Offline Weylin

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Re: When to heat treat?
« Reply #9 on: May 27, 2009, 08:03:36 pm »
once again, thanks for the great ideas. This is my first bow so if it ends up with too much set then it was a learning experience, hopefully I can still get some target practice with it even if I am not slaying elk. I think that NOMADIC PIRATE is right, I pushed the bow too far before I had it even and it took the set right off the fades. And the tillering stick didnt help, my gut told me that leaving the bow pulled that far on the stick to take time to eye it up and take pictures wasnt a good idea, guess next time I'll know better. I will make a tillering tree sooner or later (and thanks for the detailed plan, Dano). NOMADIC PIRATE, are you suggesting that I just draw the bow by hand in front of a mirror to check the tiller? That sounds like a good alternative until I get my pulley system rigged up.

Offline NOMADIC PIRATE

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Re: When to heat treat?
« Reply #10 on: May 27, 2009, 08:17:53 pm »
Drawing by hand in front of a mirror will give you a more true view of your tiller anyway, ...no way a tree can replicate the position of your drawing hand and the exact pressure of the bowhand on the handle, ..I use the tree in the early stages, but the real tillering is allways done at the mirror  ;)
NORTH SHORE, HAWAII

Offline George Tsoukalas

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Re: When to heat treat?
« Reply #11 on: May 27, 2009, 08:56:51 pm »
Your stave is doing all its bending right at the fade area, Weylin. It needs to bend more mid limb on. That's one reason, in addition to the t stick, why it is taking a lot of set. Incidentally,  how much is it taking? Jawge
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Offline Weylin

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Re: When to heat treat?
« Reply #12 on: May 27, 2009, 09:26:15 pm »
Well honestly it has been so much time since I started the bow that I dont recall if the limbs were perfectly flat or not so really it might not be as much set as it seems. The weaker limb tip is off the ground 2 1/2" but I think that limb was slightly deflexed to begin with. The stiffer limb only comes up 1 1/2 inch. Im ferociously attacking those pesky mid limbs >:(, hopefully it will start to show some progress.