Heat treating a well-used bow?

[loa]

Hello,

It's my first post here, after being a reader for a while. I have a question about heat-treating a 5 year old bow.

The bow in question is a white ash self bow with no backing of any sort, a basic pyramidal design about 2.25" at the base and .75" at the tip. It's 72" long ntn, and is about 38# at 31 inches. (Yes it's overbuilt, but it works alright and shoots smooth!) It's now 5 years old and has been shot every year until last year, roughly one evening a week, for about 8-9 months per year.

The bow has spent most of last year stored. After shooting it for 2 evenings at my club this month, I noticed that it was taking a bigger set than usual. For most of those 5 years, the bow had a 1.5" set, pretty much stable. Now it's at 3" and I'm getting worried. I can't detect any cracks or issues on the belly (forgot the technical word for it).

I was thinking about heat treating it with only a very little reflex. My goal would be to have a 2 inch reflex during heat treatment so that it would settle around perfectly straight to 1 inch of set afterward.

Does that sound like a good plan?

Thanks

Loa

[Marc St Louis]

I would recommend against it

[mwosborn]

Other than messing up the finish, heating would not "hurt" anything.  However, I don't think you will gain much over all - I think the set would return.  Maybe it is time to just make a new one  .  Can't have too many bows.

[crooketarrow]

 Once your bow gets string follow it's there and can't be fixed.
 Hang your bow up and retire it. Build another. This time try a stave.
 

[bradsmith2010]

i have a feeling the moisture content is the reason for the set,, maybe where it was stored contributed to that,,or where you are shooting it now,, is more humid,, 3 inches of set is really not that bad,, if the bow is shooting good,, if the handle is pretty stiff,,,you may be able to heat some back set  into the handle that will hold,,that would reduce the set,, but if the moisture content is too high,,, it wont help much,,, you might consider recurving the tips a bit,,, as well,, but first put the bow in a dry place,, or heat box and see what it does,, if you are just going to give up on the bow and have nothing to loose,, then cut the bow in two at the handle like a splice, and re glue it with some back set,,,,it will improve the performance if the limbs are sound,, and keep the bow in the dry house,, not storage,,

[Sidewinder]

I agree with Brad on the MC. What can be done with it is another question.

[Marc St Louis]

If the bow was Osage or HHB then I would say go for it but a well used bow of a lesser wood like Ash or Maple I say no.  I tried it on a Maple bow once and the bow developed many small fractures all along the belly and Maple is a better bow wood than Ash

[Sidewinder]

Well, I trust Marc's input so I say go to plan B. Turn it into a wall hanger for a landowner that will let you cut staves. If they are'nt ever gonna shoot it then leaving it strung and hanging on the wall looking like paleo art is a good use of materials if you ask me. You always need a few wall hangers for the non bow shootin land owners ya know. Only problem is, the longer you keep making bows the fewer wall hangers you have.

[loa]

Hello,

Thanks for all the inputs.

As far as the moisture content goes, it's stored in my house which goes from the high 50's in summer/fall, then high 20's during the winter months (in Quebec). Pretty sure it's not over moist. Right now the house hovers around 30%, and has for the past couple of months. It's been protected with many coats of boiled linseed oil.

I think I'm going to let it as it is and retire it. Problem is that it's my only shooter right now and I don't have the time nor material to make another one.

As far as bow wood is concerned, I've had trouble locating anything else but ash. I know I can find some hickory and ironwood around here (I live about an hour south east of Montreal), but I haven't been able to locate a landowner that actually has some I could buy/cut down.

Marc, I saw that you live "right next door". Any other wood you could recommend?

Thanks all,

Loa

[Joec123able]

Was it stored standing in a corner?

[Del the cat]

I believe set can be removed/reduced by heat treating.
I've done it successfully twice.
Once on my first ever Yew longbow which had been over drawn. Set reduced from 3" to 1". Bow performance better than when first made.
Second with an old dog of a "shot out" Hickory bow. Set removed, speed increased from ~ 140 to 160 fps

How about looking at it like this...
Say a bow is 50# @28" and has a ton of set.
Heat treating whilst pulling it to say 1" reflex will get it to 50# @ say 24"
If belly wood is removed to return the bow to 50# at 28" some of the most damaged (crushed) wood cells from the belly will have been removed.
The belly will now also be under less stress as the bow is thinner.
If you consider the state of the cells as you go deeper into the wood of the belly, they will go from crushed to stressed to undamaged. Some of the less damaged cells now on the outer belly will be plasticized during heat treatment and will "re-set" in their restored position.

If I play Devil's advocate I'd say:-
Ah yes, but it was just the retillering that improved the bows...
Yes BUT re-tillering won't in itself remove the set. That must have been done by the heat treating and maybe the retillering stopped it returning.

Anyhow, I think there is an element or myth to the "you can't remove set" and I feel the use of heat treating and re-tillering may be a useful addition to the pool of knowledge about heat treating ( the pool being dug and filled by Marc    )

Maybe you can't remove set from a perfectly tillered bow... but would a perfectly tillered bow have set?
I rest my case!

cited examples.
http://bowyersdiary.blogspot.co.uk/2014/04/refurb-progress.html
http://bowyersdiary.blogspot.co.uk/2013/03/big-bow-detail-and-hickory-challenge.html

Del

[adams89]

del is right. I've reduced set to 0 or even relflex on old bows i reworked when I had no staves to work on.
you can definitely "cure"set ( also on old bows) with a good heat treatment.

[bradsmith2010]

why would you give up on a bow that is shooting well,,its not like you need alot of cast to target shoot,,just go to a lighter arrow if you want to make up for the loss of cast,, 

[PatM]

 The original PA article(reprinted) mentioned heat treating as a refurbishing technique for older Yew bows.

[Marc St Louis]

Hello,

Thanks for all the inputs.

As far as the moisture content goes, it's stored in my house which goes from the high 50's in summer/fall, then high 20's during the winter months (in Quebec). Pretty sure it's not over moist. Right now the house hovers around 30%, and has for the past couple of months. It's been protected with many coats of boiled linseed oil.

I think I'm going to let it as it is and retire it. Problem is that it's my only shooter right now and I don't have the time nor material to make another one.

As far as bow wood is concerned, I've had trouble locating anything else but ash. I know I can find some hickory and ironwood around here (I live about an hour south east of Montreal), but I haven't been able to locate a landowner that actually has some I could buy/cut down.

Marc, I saw that you live "right next door". Any other wood you could recommend?

Thanks all,

Loa

I can tell you exactly where there is a humdinger of an Ironwood tree, if it's still there, that's about 8" in diameter and, from examining the bark, has very little to no twist  .  It's about 3 hours away from me and maybe 6 hours from you, it's down around Barrie.

You should have Black Locust growing where you are.  I've seen quite a bit of it in Southern Ontario and also quite a lot of it around Ottawa.  It was planted as an ornamental and has spread, heck I've even seen it growing wild up here