Primitive Archer
Main Discussion Area => Bows => Topic started by: Jon_W on April 11, 2021, 05:03:19 pm
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So here was my process that lead to this fail: I got the bow partially tillered and bending quite a bit. Then, since the wood is HHB I decided to do an initial heat treat of the belly. After I did both limbs I tried to reflex them the same day (which is where I think I went wrong). The limb that cracked had a lot of character in it so I am wondering if that had do with it too (the top limb in the side profile picture). I used dry heat to try and reflex the tips but I felt like it might have been getting too hot too. Pretty heartbreaking little *pop* but I sawed of the tips and am going to make a short and light rabbit bow out of it or something. This was my first bow attempt so I am an absolute novice. Thanks!
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I have better success boiling for a bend like that,,
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You're asking for too much bend with the wrong method of heating the wood.
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There is no need to reflex or recurve the bow, especially for a novice. If necessary, it would be a lot easier to reflex the whole working limbs while heat treating the belly mildly, than trying to recurve the tips using dry heat.
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Recurving is a neat process to learn, you have to start somewhere, we have all cracked a few.
I for one like the look of flipped tips as well as reflexing my limbs prior to tillering, these are just another skill in our bow making arsenal, none of us like to make cookie cutter bows that are the same as what everyone else makes.
I suspect you dried the limb out to much heat treating, I do the flipped tips before I do any heat treating.
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The problem here is you heat-treated first then tried to reflex. Either you reflex while heat-treating or do it before not after
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Now that it happened, I would simply v-splice a pre-recurved tip with epoxy. I would add a belly splint or underlay, if necessary.
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The actual area that cracked doesn’t look like it was heated very much if I’m seeing it correctly.
I agree with Marc to. Do your shaping first and then heat treatments. Or at the same time.
Also use a thin metal backer on belly side to help keep splinter from lifting.
Bjrogg
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When I do bending with dry heat I use cooking oil on the wood to help keep it from drying out to much, to help hold and distribute the heat. That might have helped to preventing the splintering. A bit of super glue and an overlay(underlay) would repair it.
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Thanks for the responses, I'll be proceeding with caution on the next bow and will not heat treat first if I plan to bend anything! Pat how do you remove the oil once you are done? Some of the fixes for the crack is a little over my head right now, maybe next time I mess one up )-w(
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Make a few plain bows, get your feet wet and progress to heat treating and reflexing later.
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Like many of these guys have said, the recurve should have happened before the heat tempering. Think about it this way. When you recurve you are putting tension strain on the belly, if you've just heat tempered the belly you have significantly improved the compression strength of the belly but at the cost of tension strength. That's why we never heat up the back of the bow because we don't want to compromise the tension strength there. So while the tension strength of that belly was at it's weakest you then bent it radically and asked it to do a significant feat of tension, hence the break.
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As you make more and more bows there will be steps that you will become atuned to doing in the right order for any paticular bow.Everyone has been there at 1 time or another and it takes time and perserverance.A test of patience.
You explained your problem with pictures properly.More than some do.
Jimm Hamm once said sometimes you have to be more persistant than smart but it is sometimes more important to learn from our mistakes.
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Sometimes I think if you have the persistence. Your 90% of the way there.
Bjrogg
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On the belly it usually gets scraped out while removing wood. Acetone or alcohol will remove the oil too.
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The problem here is you heat-treated first then tried to reflex. Either you reflex while heat-treating or do it before not after
^^^^^^^^^ that :)
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For those really dramatic sweeping recurves, steam is the way to go imo. Ryan's "Hunt primitive" channel on YouTube has a great video that explains how to do it on the stovetop with a pot of water and some tinfoil. )P(