Primitive Archer
Main Discussion Area => Bows => Topic started by: Oldvol on June 10, 2021, 05:00:59 pm
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Making my first recurve hickory board bow. When should I bend the tips? Before tillering, after tillering or somewhere in between? Would appreciate some guidance.
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When the limb tips are thin enough for recurving. With hickory steaming or boiling works best.Generally around floor tiller stage where the limb tips are 3/4" to 5/8" thick.
I'm moving this to "BOWS" for more exposure.
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I generally like to have mine thinner than most, 3/8 to 1/2 inch. You didn't mention heat source for bending.
I boil mine about 45 minutes, bend , set bend with heat gun as soon as they cool. Give it a day to a week depending on mood and start tillering. I also like to pay attention to belly growth rings around bend area, it seems that I have better luck if I keep the bend within a growth ring. If a ring runs out in area I'm bending I am more likely to raise splinters or belly cracks there. Good luck!
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For hickory I like my tips 1 wide and 5/8 thick. I steam them for 40 minutes then bend on my recurve caul. Good luck.
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Thanks to everyone for the info. Just started long string tillering. My tips are currently at 1/2 inch. Guess I better bend them. Plan to boil them. Now to make a bending form.
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Decided to tiller part way before bending. Currently drawing 40#@19 with a short brace (4). Ready to bend. Tips are 5/16 thick. One tip has some grain run off on one side. Afraid this will splinter during bending. Is there any way to wrap or reinforce this area?
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You should round the edges before bending. Unless you want a low draw weight bow then 5/16" might be a bit too thin for recurving, as in they might pull out.
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Unless the bow is very short, under 50, its rarely the case that the limb tips should get so thin even for a fully tillered bow. Got any pictures and more stats for your bow?
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My 1st successful bow was a pyramid bow 66 long with 3/16 thick tips but the draw weight was only 30#. This bow is a flat bow 66 long, 1 3/4 wide, with taper starting 12 from the tips. I thought thinner tips would bend easier. Did not think about possibility of recurve pulling out. Would heat treating belly after curving help prevent that? Hoping for 40# pull but it may be too much for me.
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You could bend some thin strips to use as underlays on the same form as that you bent the recurves, glue them in place and shape the tips. This will give you static recurve tips.
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Thank you Pat B. Two questions. How thick is thin - 1/16, 1/8, etc. and should I glue them on before I finish tillering?
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I'd glue the underlays on shortly after bending the recurves so you stiffen the tips before they are strained. I'd go with a 1/8" thick underlay. You can always thin the tips later. Also, leave the tips wide, 3/4" to 1" until after the recurved are bent, the underlays are installed and you are sure the tips line up with each other along the back and the string tracks well. The extra width can help with the line up. Also, leave the handle blocky for later possible adjustments. Once everything lines up you can reduce the width of the tips to reduce physical weight.
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Heat-treating will help to set the recurve in.
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I live in a dry climate. If I want sharp(contact) recurves I soak the tip in a glass of water for a few days before steam bending or they will crack. Since I rehydrate the wood I need to wait 10+ days before I bend the bow again.
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Many thanks. I intend to do exactly what each of you have advised. Should I use Super Glue or Titebond III?
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TBIII. Be sure the glue surfaces and well matched and mated.
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Thank you. Will do.
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Bent the first limb of my bow yesterday. Boiled it 20 min. in a pot covered with aluminum foil. Bow went on the caul easily, but had a hairline crack across entire width at top of the bend. Let it cool for 6 hours. Then started heat treating the belly with both ends of the limb still clamped to the caul. BIG mistake. As the limb heated up the crack became more pronounced.
Bent the 2nd limb today and all is well so far. Have not heat treated it yet. Hope to repair the 1st limb with glue and then back both with a thin strip of cherry. Anyone have advise on repairing the crack?
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There is no need to apply more heat after steam bending. I've bent some pretty sharp recurves by boiling them. They will not pull out or change shape once cooled. I'm not sure why this technique is beng used now.
You can of course heat treat the belly after the tips have cooled but you will need a form to clamp the curves to to prevent them 'uncurling' as you apply the heat. This is a different thing though.
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If your tips are 1/2, steam for a half hour, 5/8 tips steam for 45 min. I typically steam at least a half hour if not more just to prevent any mishaps. I also leave it in the caul over night and dont do any bending for a couple days. Again just how I do my recurves.
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There is no need to apply more heat after steam bending. I've bent some pretty sharp recurves by boiling them. They will not pull out or change shape once cooled. I'm not sure why this technique is beng used now.
You can of course heat treat the belly after the tips have cooled but you will need a form to clamp the curves to to prevent them 'uncurling' as you apply the heat. This is a different thing though.
Every one I've tried without setting with heat have pulled out. Maybe it has to do with wood type? I don't know, I just know that's why I started setting them all.
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There is no need to apply more heat after steam bending. I've bent some pretty sharp recurves by boiling them. They will not pull out or change shape once cooled. I'm not sure why this technique is beng used now.
You can of course heat treat the belly after the tips have cooled but you will need a form to clamp the curves to to prevent them 'uncurling' as you apply the heat. This is a different thing though.
Almost all of my recurves would spring back or pull out slightly after heating but I was also using what I think is a less effective method of steaming. Since using a heat gun to set them theyve worked significantly better with zero spring back and only a bit of heat. I also have a new steaming setup that gets way hotter so Ill have to see if I can skip the dry heat after.
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I'm in the boil only camp, never had an issues with them pulling out, but then again I don't ever do the really sharp 90* hooks. I just boil and set until the wood cools and then wait a day to start working on the bow again.
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If the wood is a couple rings thicker at the recurves than the thinest part of the working limb then it's unlikely they will pull out just from wet-heat bending
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I pretty much have followed the same guidelines and procedure as stixnstones. The results have been positive.
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Can someone tell me how much more a recurved tip would be stressed at full draw, compared to a straight tip?
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TB3 is what I would recommend. It has always worked well for me on under-lays as well as tip overlays. Make sure you get a tight glue line. Good luck
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Thanks to all.
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Can someone tell me how much more a recurved tip would be stressed at full draw, compared to a straight tip?
Steaming or boiling wood weakens it a bit plus the limb is stressed more with recurves then there's the angle of the string focusing more stress on the recurve
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Can someone tell me how much more a recurved tip would be stressed at full draw, compared to a straight tip?
Steaming or boiling wood weakens it a bit plus the limb is stressed more with recurves then there's the angle of the string focusing more stress on the recurve
Thanks. That's the kind of answer I like, instead of a math or physics formula I have no way of following. But I would accept such formula if the provider has enough credentials. I still prefer to have the "ordinary language interpretation" of such a formula. And that should be comprehensible to average people. Thanks in advance.
It is intuitive for the limb to be more stressed by a recurved tip. However it is not that intuitive for me how the recurved tip itself is more stress than the straight tip. Am I having a senile moment?
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Can someone tell me how much more a recurved tip would be stressed at full draw, compared to a straight tip?
Steaming or boiling wood weakens it a bit plus the limb is stressed more with recurves then there's the angle of the string focusing more stress on the recurve
Thanks. That's the kind of answer I like, instead of a math or physics formula I have no way of following. But I would accept such formula if the provider has enough credentials. I still prefer to have the "ordinary language interpretation" of such a formula. And that should be comprehensible to average people. Thanks in advance.
It is intuitive for the limb to be more stressed by a recurved tip. However it is not that intuitive for me how the recurved tip itself is more stress than the straight tip. Am I having a senile moment?
I would think that the stress would be equal (within reason) to the length of move, but I have found my reason doesn't always apply.
In other words, if a recurve moves 4", it would be the same stress as if the straight limb moved 4". But since a recurve changes the angle of the string, it changes the leverage, so I would think it travels less. If it's a stiff tip, the travel would less for that section.
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I was wondering why boiled or steamed recurve tips would be pulled out, when there is so little stress at the straight tips as to to allow them to be pencil thin. If that's simply because the tips are way in front of the straight bow back line, does that mean the tips of a reflexed bow should be as thick as the static recurve tips?
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Bends are completed (about 45 degrees) and look good. Repaired tip looks good. Currently bending overlays.
Recurving the tips and heat treating the belly completely changed the character of the wood. The bow is much, much stiffer than before. Previous tillering was a waste of time. Question: when I begin retillering do I scrape all the way to the end of the tips or just to the beginning of the bend?
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Pictures of current state:
https://downloads.flickr.com/s/20210706afac6cfc35afa409f2abef6f09e788e303e0ee1d13fb480289d3643de74f3e0d.zip
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/Users/jerrydraper/Downloads/20210706afac6cfc35afa409f2abef6f09e788e303e0ee1d13fb480289d3643de74f3e0d/Users/jerrydraper/Downloads/20210706afac6cfc35afa409f2abef6f09e788e303e0ee1d13fb480289d3643de74f3e0d
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Trying to post pictures using Flickr. Haven't figured it out yet.