Author Topic: Heat treating experiment gone wrong  (Read 1953 times)

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Offline eastcreekarchery

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Heat treating experiment gone wrong
« on: December 06, 2020, 01:49:10 pm »
So I had a small piggy back stave from another stave I'm going to turn into my next bow. I decided to chase a ring on it and turn it into a little bow to use for heat treating practice with the intention of seeing how much I could bend it until it broke. Unfortunately that experiment failed and the bow didn't break at the point I thought it would so I decided to tiller it into a usable bow. I heat treated the belly till it was a toasted color and it increased the draw about 10 pounds. The finished bow has taken a lot of set, and I believe it's because the short, narrow limb design is not ideal for black locust as it can be weak in compression and I also tillered it to bend quite a bit in the handle, which really accentuated the set towards the limb tips. It has a lot of hand shock so I wrapped some cloth around the bow to build up a handle. The "paint" job was done with some sharpies. I also made my first ever bow string for this bow, an 8 strand flemish twist made from artificial sinew. 48# @ 25." It's been a good learning experience for me. I was wondering if I could reflex the tips with steam but I'm not sure it's a good idea since the limbs have been heat treated.

Offline mmattockx

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Re: Heat treating experiment gone wrong
« Reply #1 on: December 06, 2020, 01:59:10 pm »
I heat treated the belly till it was a toasted color and it increased the draw about 10 pounds.

It's hard to tell from the pictures (or I'm missing it, which is very possible), but did you also add a bunch of reflex when you heated it or did you just heat it while flat? That is a massive amount of bend shown in the full draw picture, impressive to see it survive that.


Mark

Offline eastcreekarchery

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Re: Heat treating experiment gone wrong
« Reply #2 on: December 06, 2020, 02:04:25 pm »
I heat treated the belly till it was a toasted color and it increased the draw about 10 pounds.

It's hard to tell from the pictures (or I'm missing it, which is very possible), but did you also add a bunch of reflex when you heated it or did you just heat it while flat? That is a massive amount of bend shown in the full draw picture, impressive to see it survive that.


Mark
i heated it while it was flat

Offline eastcreekarchery

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Re: Heat treating experiment gone wrong
« Reply #3 on: December 06, 2020, 02:05:00 pm »
I forgot to add the bow length is 49” ntn

Offline bradsmith2010

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Re: Heat treating experiment gone wrong
« Reply #4 on: December 06, 2020, 02:12:02 pm »
nice experiement,, glad it didnt blow,thats positive for sure,,

Offline mmattockx

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Re: Heat treating experiment gone wrong
« Reply #5 on: December 06, 2020, 02:17:20 pm »
i heated it while it was flat

So your 10lb gain is solely due to the heating, that is a great reference point to have. Most guys heat in reflex while they are at it and you never can separate the weight gained from heat treating from the weight gained due to the reflex.


Mark

Offline George Tsoukalas

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Re: Heat treating experiment gone wrong
« Reply #6 on: December 06, 2020, 02:53:09 pm »
I think it looks good and you are getting a lot from such a short bow. Jawge
Set Happens!
If you ain't breakin' you ain't makin!

Offline Morgan

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Re: Heat treating experiment gone wrong
« Reply #7 on: December 06, 2020, 03:04:49 pm »
That little dude is BENDING! you got all out of it as you possibly could I believe. As much as she’s binding in the center, you are gonna have to eat the shock i think. If you make another like it, you could lessen the jolt for lack of better term by losing some mass in the outer limbs it looks like to me.

Offline eastcreekarchery

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Re: Heat treating experiment gone wrong
« Reply #8 on: December 06, 2020, 05:45:32 pm »
i heated it while it was flat

So your 10lb gain is solely due to the heating, that is a great reference point to have. Most guys heat in reflex while they are at it and you never can separate the weight gained from heat treating from the weight gained due to the reflex.


Mark
thats a great observation. I'll use it in the future.

bownarra

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Re: Heat treating experiment gone wrong
« Reply #9 on: December 07, 2020, 12:22:47 pm »
It is bending too much in the center and the lower limb needs to bend more progressively in the outer 2/3rds.
The handshock is due mainly to the excessive bend in the handle area. You can also get some shock when either the limbs are out of balance, strength-wise one to the other or the tiller/bend isn't correct for the limb profile.
Its all a learning curve and the only way to learn is to make shavings :) Good luck with your future bows.

Offline Morgan

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Re: Heat treating experiment gone wrong
« Reply #10 on: December 07, 2020, 07:40:17 pm »
It is bending too much in the center and the lower limb needs to bend more progressively in the outer 2/3rds.
The handshock is due mainly to the excessive bend in the handle area. You can also get some shock when either the limbs are out of balance, strength-wise one to the other or the tiller/bend isn't correct for the limb profile.
Its all a learning curve and the only way to learn is to make shavings :) Good luck with your future bows.

Bownarra,
I have never made a bow that short and also never made one with draw length of more than half the length of the bow, so correct me if I’m wrong here.
I can see the stiff outer limbs, but I do not think he would have gotten that draw length without them. If they came around more, string angle would be well over 90° I believe. I think the only way he got the draw length he did out of that is because of where it is bending.
Am I seeing it or thinking of it wrong?

bownarra

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Re: Heat treating experiment gone wrong
« Reply #11 on: December 08, 2020, 12:08:02 am »
These things are subtle. Yes it needs to bend in the handle area but not that much. The lower limb is almost straight at full draw...
Leaving the outer limbs stiff on an already too short bow will just kill the return speed of the center wood and it will buck like a mule.
A better way to avoid string angle issues would've been to recurve the tips.
Tiller logic always wins :) and of course the set will show what I mean.