Primitive Archer
Main Discussion Area => Bows => Topic started by: Selfbowman on January 09, 2024, 10:40:18 am
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Has anyone ever taken a bow with set or heat treated a finished bow to say 300-350 degrees and brushed hide glue into the hot opened pours of the wood and the let it cool for a couple days . If so what was the results?
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Marc St Louis, in his chapter on heat treating in TBB-IV wrote about adding thinned spruce pitch into the hot, tempered belly of the bows he built.
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I remember years ago when Marc did his testing. There was also talk of soaking using heat and wood hardeners, but it seems like they were brittle. Maybe your idea would do it...I know you're going to try it. :) Another choice might be heating back into original shape, and then soaking in a penetrating waterproofing of some sort? It will be fun to see what comes up.
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Okay, the subject says questions and answers so I guess I’m not hijacking The thread if I ask one am I. If I am I apologize.
Question
I have a yew bow I built last year that took about 2-3 inches of set. Would it help it if I put it on a reflex form and heated it then put rawhide on the back. It shoots okay and seems to have decent cast. Or should I just love it for what it is.
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Bob I’m thinking put it back on the caul and heating the bow up and brushing on the hide glue as I go down the limb. I have a bow I’m working on that started out 3-1/4 tips in front of the handle . I think at least a 1/2” just pulled out. It’s now 2-1/2”. Ya I’ll probably try the hide glue.🤠I’ll let you know.
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Okay, the subject says questions and answers so I guess I’m not hijacking The thread if I ask one am I. If I am I apologize.
Question
I have a yew bow I built last year that took about 2-3 inches of set. Would it help it if I put it on a reflex form and heated it then put rawhide on the back. It shoots okay and seems to have decent cast. Or should I just love it for what it is.
Hey mike. It would depend on wether you had previously put heat to it for corrections and such and how long. Yew does see benefits to heat but not like white woods or even Osage in my opinion. It tends to get brittle with too much heat in my experience. If you have not applied heat yet to the belly then you may see some marginal results with a little heat on belly but if this bow has already been compressed and stretched wood fibers out to full draw it may not see much benefit. If it shoots good now I might just leave it be. If it is not up to my expectations I may be tempted to sinew back it and do a few scrapes on belly to get back to weight. Rawhide will be a good protective cover but not provide any cast enhancements from my experience. Hope this helps ya
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Bob I’m thinking put it back on the caul and heating the bow up and brushing on the hide glue as I go down the limb. I have a bow I’m working on that started out 3-1/4 tips in front of the handle . I think at least a 1/2” just pulled out. It’s now 2-1/2”. Ya I’ll probably try the hide glue.🤠I’ll let you know.
I e not tried hide glue to this extent and purpose but have done this to a lesser degree of heat on belly of horn bow build to get the wood cells good and opened up to more readily accept the sizing glue.
I have used Marc’s method with good results. He has a video showing the process online I think that I referred to. I also used his method and used “cactus juice”. It’s a hardening heat activated resin that hardens at around 250 degrees. I had a bunch of this left from my knife building days for stabilization of wood handles. I found that this added some mass but also hardened up the belly. It likley added some waterproofing too but cannot say to what extent. I just used a heat gun set up and crept along and brushed on the liquid resin with a brush and it soaked into belly wood and hardened at same time. I’ve done this with bamboo self bows hickory and maple.
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I have used Marc’s method with good results. He has a video showing the process online I think that I referred to. I also used his method and used “cactus juice”.... I found that this added some mass but also hardened up the belly. It likley added some waterproofing too but cannot say to what extent.
Hi Dave
with either "Marcs method" or "his method with Catcus juice" can you share a little more about what the good results were performance wise?
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One strange thing I have noticed about yew is that a gentle heat soak can relax a small amount of set out of a bow. I gently and slowly heat the bow until I feel the back begin to warm, very little colour change on the belly. I don’t use a caul for this
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I have used Marc’s method with good results. He has a video showing the process online I think that I referred to. I also used his method and used “cactus juice”.... I found that this added some mass but also hardened up the belly. It likley added some waterproofing too but cannot say to what extent.
Hi Dave
with either "Marcs method" or "his method with Catcus juice" can you share a little more about what the good results were performance wise?
I’m not certain as to any performance increase per se. The reason I say this is that I noticed an increase in mass afterwards. A one step forward and then a step back. Give and take situation in my estimation. Ya it increased the belly hardness on the ones I did but with the added mass it was a wash in my opinion performance wise. I did notice a slight speed increase in one of the bamboo bows I tested initially but this settled into previous numbers after some shooting. I think that it may have some other benefits too though like the ability to seal up and more deeply seal up the belly wood from some moisture I suspect. The hickory also saw no speed lasting increase at all and did not seem to see any difference in speed or the way it cast an arrow. Very slight increase in mass due to the resin using marks method. I did test on couple hickory bows one that was previously heat treated over coal bed (medium cook) and noticed more of an increase in mass then the other. Can’t remember the number in grams but it was little more then heat treat with heat gun and applied resin as I went along. I have to think this had something to do with level of moisture is pushed out with coal bed cook vs heat gun. At least as far as I’ve been doing it. Results I’m sure would vary. The previously heat treated bow again settled into previous speeds prior to resin heated in. More testing would be needed I think to determine clearer results I believe. I’ve often wondered what affects would be seen if one was to vacuum pressure a set of limbs in a chamber with resin. I’ve made a vacuum chamber for wooden knife scales to wether proof them and just keep it running till bubbles stop and the wood is fully saturated with resin. I would then bake them according to the instructions for the resin. I wonder what performance if any might be had in doing this. Not very primitive for sure but might be cool experiment.
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but with the added mass it was a wash
I think Mark (Mattockx) mentioned this as a reason why glass bows designs rarely outperform wood in speed.
I would then bake them according to the instructions for the resin. I wonder what performance if any might be had in doing this. Not very primitive for sure but might be cool experiment.
Perhaps saturate only the belly lam before glue-up? I would imagine the resin weight penalty would increase if applied to parts of the crossection that do not need compression enhancement
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Has anyone ever taken a bow with set or heat treated a finished bow to say 300-350 degrees and brushed hide glue into the hot opened pours of the wood and the let it cool for a couple days . If so what was the results?
micro photographs of wood cells look like bundles of straws. once a cell wall starts to collapse (take set), I suppose filling the pores could help, but the damage is done and the fix is like a splint
why not fill the pores before the cell are compromised? might help then from taking set sooner.
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Willie i agree but my thought was to get as close to final tiller as possible so we can get the full advantage. Maybe do it at 20 “ of draw . That’s when set starts for me. The thing is when you are trying to hit as close the 50 as possible for flight bows it’s hard to hit your weights doing this to soon.
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that makes sense.
so in the other thread about daves tillering yardstick mod, it occured to me that if one could make a bow that was perfect (well, as close to perfect as possible) at brace, then in theory one could have a winner with the first few shots. OK. thats impratical for most, but it did get me thinking about how the average bowyer would know what perfect at brace height would look like?
Unless he was like Arvin! ;D
1. settle on a design that works
2. keep accurate tracings and weight records on previous builds
3. build to spec.
I think Badger tested a bow built by Dave Dewey thqat was built to spec and never drawn previous to testing. maybe Steve can comment on how close to tiller it came out, I do recall it performed rather well.
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Okay, the subject says questions and answers so I guess I’m not hijacking The thread if I ask one am I. If I am I apologize.
Question
I have a yew bow I built last year that took about 2-3 inches of set. Would it help it if I put it on a reflex form and heated it then put rawhide on the back. It shoots okay and seems to have decent cast. Or should I just love it for what it is.
I've rejuvenated bows by heat treat, these posts from my blog show what can be done:-
https://bowyersdiary.blogspot.com/2013/03/big-bow-detail-and-hickory-challenge.html (https://bowyersdiary.blogspot.com/2013/03/big-bow-detail-and-hickory-challenge.html)
https://bowyersdiary.blogspot.com/2013/03/hickory-challenge-result.html (https://bowyersdiary.blogspot.com/2013/03/hickory-challenge-result.html)
I've done similar with Yew bows. Any bow can get a bit tired after years of use. The main thing is to correct any minor tillering issues at the same time as the heat treating.
Del
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Thanks Del I new someone had tried this . I never do anything new just revive someone else’s Pryor thinking. 🤠🤠
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I think Badger tested a bow built by Dave Dewey thqat was built to spec and never drawn previous to testing. maybe Steve can comment on how close to tiller it came out, I do recall it performed rather well.
That was woodbear's red oak challenge bow. He designed it with his spreadsheet, cut it to the dimensions from the sheet and worked it up to brace just to be sure it looked OK and then sent it to badger. Steve then exercised it out to 28" (or whatever the test draw length was) and test shot it. IIRC it came in a few pounds heavy, so badger then tillered it back to the target draw weight and tested it some more.
That red oak lam bow of mine you dredged up out of the swamp the other day was done similarly. I built the bow completely from calculated dimensions, put it on the tree and just worked it out to 28" with no tillering at all. The bend you see in the pics is how it came off the form with no tweaking at all.
Mark
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Has anyone ever taken a bow with set or heat treated a finished bow to say 300-350 degrees and brushed hide glue into the hot opened pours of the wood and the let it cool for a couple days . If so what was the results?
I'm thinking the 350 degrees might be a bit too much heat for the hide glue
I used conifer resins but I also tried tung oil, didn't seem to make any difference
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....with no tillering at all. The bend you see in the pics is how it came off the form with no tweaking at all.
Mark
I dunno if a bow shot in the unlimited class needs to be tested for draw weight prior to shooting in competion, or even if a 51 lb bow could be competive in that class, but the possibility of shooting a previously undrawn bow is intriguing.
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I dunno if a bow shot in the unlimited class needs to be tested for draw weight prior to shooting in competion, or even if a 51 lb bow could be competive in that class, but the possibility of shooting a previously undrawn bow is intriguing.
About 10 years ago I built a bow and only tillered it out to about 23" and then projected the draw weight out to 28". So, it's not 100" accurate but very close. When I tested the bow I rapidly took it right to 28" and got phenomenal speed. ( It was a very extreme recurve design. The first shot was the fastest at 215 fps and it went steady down with each shot until it got down to 157 fps and lost about 18#. It settled in at about 178 fps with 10 grains per pound.
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A couple things to consider would be moisture lost to evaporation and moisture absorption upon contact with the wood. I’m not sure how that would impact any absorption of glue particles into the wood. I’m also not sure if hide glue is even small enough to fit into wood other than larger gaps in the grain like the early wood. I know PVA glued only interact on the very surface so I wonder if hide glue is similar.
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Ryan I hear ya. I know that the wood opens up With heat. Just was wondering if glue of some kind might be a fix for the compressed belly. Also this is a good thread that could have other questions I guess.👍