Author Topic: Heat treated elm bow  (Read 1773 times)

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Black Moshannon

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Heat treated elm bow
« on: May 10, 2020, 07:29:44 am »
I finished this bow a week ago. It was from a small diameter elm tree. I don't know the species, most of the elm around here is red elm but its not that. Its 67" long by 11/8-11/4 wide at the widest, bend through the handle. It is my third heat treated bow that held together. I began by drying it out to around 8 percent and floor tillering it. Once that was done I got a string on it. I left it fairly wide, around 1.5 inches. This was so I could later heat treat it and then tiller by narrowing only, to preserve all the toasted belly, and because leaving it wide helps me deal with making corrections to tips laying straight. On this one, the lower limb has a propeller twist which I left in and worked around. This caused me some grief later. The lower limb also has a concave spot on the back which I compensated for by leaving a convex spot on the belly.

After getting the string on and messing around with the tiller some, the bow started taking on some bad string follow. I didn't measure but it had to be over two inches. I steamed setback into the handle and some reflex into the ends. This left it with about an inch of reflex total. I dried it back out and then tillered it to 60# at 26". The goal was to get it to 60#at 24" and then heat treat and re-tiller to 27" but I was too timid in the bending stage and went overboard on wood removal to get it bending in a safer way (at least that's how I felt about it). It had 1.5" string follow after being drawn and went to 3/4" after resting. It was between 11/4" and 11/2" wide.

I reverse braced it to about 1" reflex and heat treated it for 1.5 hours over some coals. It took a very even color. I let it re-hydrate for six days and then re-strung it. I tillered it almost entirely by narrowing the sides. Initially it was at 60# at 24.5". I tillered it to 60# at 26". It was narrowed down to somewhere between 11/8" and 11/4". I cut in what I thought were some decent string nocks, taking into account the twisted lower limb. It worked ok with a knot in the lower limb.

I applied tung oil and made a linen string. Once I had it strung with the loop on the lower nock, the string kept popping partway off the nock, because of the limb twist shape and the nock shape. I had to re-file the nock shape to fit the way the string was laying.

After several coats of tung oil I shot it and drew it and have been playing with it, and all seems great. The bow now has 11/8'" of string follow, which goes to 11/2" after drawing/shooting. If I had it to do over, I would have removed the propeller twist in the lower limb right away. I have never removed propeller twist but I hear its not hard. Right now, the ends are in line with one another and the string lays just slightly off to one side, which is the side I shoot off of. Pictures are included. Critiques, comments and questions are welcome.

Black Moshannon

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Re: Heat treated elm bow
« Reply #1 on: May 10, 2020, 07:31:38 am »


More photos.
« Last Edit: May 10, 2020, 07:37:47 am by Kenneth »

Offline bassman

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Re: Heat treated elm bow
« Reply #2 on: May 10, 2020, 08:24:32 am »
Elm loves heat. Staves with limb twist , and need the tips lined up with the middle of the handle can be done in one step with a heat treat added before it ever comes off of the form after floor tiller providing the twist ,and warp is not to radical. Make a form of your preference. Start from the handle working both ways, and with dry heat line the limb tips up with the middle of the handle, and place the clamps to roll the twist out as you go. Then give the belly a good heat treat before you take it off the form. It should then be ready for tiller, and you can tweak here, and their as needed.This method has worked best for me when getting a stave straight, taking twist out of the stave, and minimizing set in the tillering process.Their are many ways to make a good bow . This is just my way.

Black Moshannon

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Re: Heat treated elm bow
« Reply #3 on: May 11, 2020, 06:42:08 am »
I've not used a form yet, but have been wanting to try it. I'll have to make one up and try this out.

Offline StickMark

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Re: Heat treated elm bow
« Reply #4 on: May 11, 2020, 01:48:36 pm »
Looks stout,  looks great.

Offline willie

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Re: Heat treated elm bow
« Reply #5 on: May 11, 2020, 02:08:12 pm »
Kenneth,

looks like you are certainly willing to experiment with different techniques.

Has most of the set been taking place in the center of the bow? Sometimes the thicker handle area is the last to dry properly.

Black Moshannon

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Re: Heat treated elm bow
« Reply #6 on: May 11, 2020, 03:15:25 pm »
It seems from the photos like most of the set is in the middle of the bow, and the least towards the tips. Looking at the photos of me drawing the bow on the desktop, it seems to really have exaggerated the look of the bend towards the middle, the photos are kind of warped looking. Still it does appear I could have gotten the tips bending more. I believe the middle was as dry as the tips as I had used the moisture meter prior to heat treating. The center of the bow was also the darkest treated. I really meant to get those outer limbs moving more. Looking at the bow in person, if I remember right, it seems like the handle area was fairly flat and the set was evenly distributed throughout most of the bow, getting less towards the tips. I'll have to examine it when I get home.

Offline Hamish

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Re: Heat treated elm bow
« Reply #7 on: May 11, 2020, 04:27:47 pm »
As you have already recognised, the bow looks to be bending too much in the middle, and not enough from mid limb out to the tips for the designs width profile. Its not a bad bow by any means, it just looks like it might have more hand shock than is ideal?

If you do another one and use what you learnt in this one, you will end up with an excellent bow.

Offline willie

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Re: Heat treated elm bow
« Reply #8 on: May 11, 2020, 04:38:34 pm »
If you do another one and use what you learnt in this one, you will end up with an excellent bow.

+1

getting the outers bending early and bringing your desired bend into the center as you get closer to final drawlength helps with bendy handled bows

Black Moshannon

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Re: Heat treated elm bow
« Reply #9 on: May 11, 2020, 05:01:57 pm »
Thanks for the advice. I'll have to focus on this for my next D-bow, another elm.

Offline burchett.donald

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Re: Heat treated elm bow
« Reply #10 on: May 11, 2020, 07:31:18 pm »
 Kenneth,
               Copied and tried to correct pic for you...Agree with you on the outters needing to move more on the next one
                                                                             
         PS Some times those stiff outters keep string angle down though, so not bad at all...
                                                                                                                                       Don
                                             
« Last Edit: May 11, 2020, 07:35:02 pm by burchett.donald »
Genesis 27:3 Now therefore take, I pray thee, thy weapons, thy quiver and thy bow, and go out to the field, and take me some venison;

Black Moshannon

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Re: Heat treated elm bow
« Reply #11 on: May 12, 2020, 05:58:09 am »
 Thanks for the photo, that is how it looked before I posted it. I might be messing around with more of a whip tiller next time, just to see if I can do it. I think most of my bows don’t bend enough towards the ends.

Offline BowEd

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Re: Heat treated elm bow
« Reply #12 on: May 12, 2020, 06:13:31 am »
Nice bow.We've got that red elm here too.I can't seem to get much more than 50 to 60 pounds from it though even as a flat bow.It gets too wide then to suit me.
BowEd
You got to stand for something or you'll fall for anything.
Ed

Black Moshannon

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Re: Heat treated elm bow
« Reply #13 on: May 12, 2020, 02:46:19 pm »
One of my red elm D bows I made half heartwood and half sapwood and the red heartwood made a really beautiful contrast. It's my favorite bow right now, 60# at 27". Red elm seems to be pretty soft wood and works easy. I don't know how it would match up against other elms. I haven't seem american elm in a long time. I remember it seemed to be a harder, tougher wood. It had a beautiful grain too.