Primitive Archer
Main Discussion Area => Bows => Topic started by: upstatenybowyer on December 18, 2016, 06:07:54 pm
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Some of you may have seen one of my recent posts, "there's a hole in my belly." Well, the bow is tillered out, shooting amazing, and as I'm applying finish, I notice this small chrysal just above the hole that I filled with CA. I'm referring to the line just above the hole on the left. There's a clamp mark a little higher on the right, and that is not a chrysal. Any fix ideas? I thought about wrapping over the hole and chrysal with sinew or, gluing a very thin lam of horn over it and then wrapping. I really don't want to loose this bow! Thoughts?
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could we see the bow at full draw,, whats the clamp mark from,, did the crysal come from clamping or shooting,,
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full draw
sorry about the stupid look on my face ;D
I had the bow clamped over the glue-filled hole while I heat treated a little bit of reflex into the mid-limb. I didn't notice the chyrsal until after I shot it a bit.
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and here's a shot of the belly so you can see where the glue filled hole is (just below the handle)
the wood is HHB
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You can always give the bow a trapezoid cross section by narrowing the back by about 10-15% of the belly width. Most woods are stronger in tension than they are in compression, this will help even the forces.
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upstate....Right now I'm sure it is'nt showing anything in change of tiller or anything.The bow looks fine.How much shooting has it done?It has'nt migrated across to the edges of your limb.If and when it does that your tiller will change then.Pretty much end of story then too.Those chrysals are a kind of use it wait and see kind of thing,but in time with more and more use they seem to get worse.There is a possibility yours won't.No way to say this all kindly.I've seen these things not develop more or get worse even after 2000 shots but eventually they did.If the bow is not a stressful design with good length and width it could last a very long time.
Now I have seen but not done people who have taken a section of wood out and replaced it matching surfaces perfectly.The people who have done that could comment.If you're really wanting to try to save the bow that's what I would do.
PS....You know using buffered pads of wood will eliminate those clamp marks.
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Bead, thanks for the reply. I decided to take a file to it and low and behold, it disappeared! It must have been very shallow. There are no other chrysals on the entire belly so I think I'm in the clear (fingers crossed). I've got some finishing touches in mind so I guess I'll get to it and post the bow when it's done. Thanks again.
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I wonder if the superglue was too hard of a substance to fill a hole of that size. I doubt superglue compresses the way a good bow wood does. It may crush the wood above and below, kind of like closing a door with a stone stuck in the jam. I use TB mixed with powdered antler or sawdust. It seems to be a little softer/ squishier than superglue.
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Why are you pulling it back so far? It's not a Compound Bow.
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Why are you pulling it back so far? It's not a Compound Bow.
+1
And, the lower limb seems to be bending more than the upper...
If you ever do need to repair a chrysal, there are ways to do it.
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I hope this bow survives- either way, it's a great teaching bow. Generally, a chrysal is caused by wood bending too much and failing in compression. If the chrysal is not too advanced, you can sometimes halt it's progress by fixing the problem. The problem is too much bend. To make it bend less, add wood to the area or remove wood everywhere else. heat treating may also be an option. I also wonder why you're pulling it to your ear- was it designed to do that? If not, a few extra inches of draw like that will cause unnececary set (or even chrysalis). Sanding or filing away a chrysal seems like the opposite of what would work.
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Unfortunately there is no real fix for chrysals. A chrysal happens because the wood has been crushed, the amount of compression on that spot was too great for the woods ability to resist it. Its like a person lifting a weight that is too heavy for them and tearing a muscle. Sure you can put a bandage on it but that doesn't mean the muscle is fixed...fortunately we heal but wood doesn't. Once you have taken it past its limits that is it done. In my opinion its a waste of time trying to fix it. I only say that now because I have tried all the different methods to 'fix' them. I've done Dean Torges scoop method and whilst they do hold well it is not ideal. The butt joint method is worth trying for the experience but a butt joint in a working limb will open a little over time.
Best fix for a chrysal.....start again ;)
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And for future staves with knots like this you should have left extra width around that area when shaping the width. Say that knot is 1/2 inch across, there should have been an extra 1/2 inch width at that area. This would have meant that that area had the same amount of clean wood to do the work instead of as it is now with no added width.
Imagine the grain of wood being like water in a stream. Grain flows around knots like water flows around a rock. You can see this in your picture.
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Thanks for all the input folks. This has definitely been a great learning bow.
It was designed to pull further than my draw length, as it was intended to be a Christmas gift for my brother-in-law (he has a 30" draw length).
Mike, I think you're right about there being no real good fix for chrysals. I'm hoping I got lucky with this one, as it only took 2 or 3 strokes with a file to remove it. Going forward I will definitely leave extra width around spots with holes such as this one. There are still so many things I don't know about making bows.
Asharrow, the picture does make it look like the bottom limb is bending more. It may be the camera angle, as it does not appear that way on the tillering tree with the bow resting horizontally.
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upstate....That's great you were able to file it away.That can happen too.The way I check that for sure is to put a little laguer on the area and it will show if there is a crack.I used to use saliva but laquer dries up quicker.
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upstate, I was not able to see it.
Filing away a weak spot makes it weaker.
I leave knoted areas wider and typically tiller large knots to appear a little flatter than the rest of the limb.
Jawge
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does look like it might have been bending a bit much there,,
if you have any extra weight,,tillering a bit more to leave that area stiff might help, but as Beadman said ,, it might be ok as is, hard to say,,
I still have a feeling it might have agravated that part of the bow when you heated it to bend it,, hope it works out,,
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I had my favorite hunting bow fret on me right before hunting season this year it had at least 2000 arrows threw it before it showed up , there where a lot of good suggestions here how to fix it but most where last ditch try & see kind so I decided to take my learning lumps switched to my back up & started a new bow , it was areal kick in the gut but learned a lot from it.
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Well if you are keeping it for yourself you don't have to pull it to 30" anymore right? I would think that might be a "fix" but I would listen to the real experienced bowyers too
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You can sand or file away a cryshal but it will come back you just can't see it at the moment
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Posted this earlier, but nobody paid any attention. This was a repair of a void, but the same process works for chrysals.
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I have done partial belly lam several times. It worked for me probably because I usually make light weight bows around 40 pounds. The main idea IMHO is to leave the problem part a little thicker than other parts.
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I don't inderstand the need to fix it. Yes you want to avoid them and having too many will cause unnessasary set or string follow, but most bows won't break in compression as far as i understand, even if they have a whole bunch. I would think trying to fix it will make it worse. I'd leqve it, and if you really don't trust it make a new bow.
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The bottom limb is definitely working too hard. It may not look that way to you on the tree but drawing it by hand will reveal the true tiller. sometimes the tree doesn't tell the whole truth. I've had that happen to me before. If it were my bow would significantly weaken the top limb to get it bending properly. (I like my top limb bending a hair more than the bottom.) Only then will the bow have a chance to ultimately survive. You have to take the pressure off that spot (especially since you weakened it further by filing away the chrysal. It may still ultimately fail but that's your shot at success, in my opinion. It's going to mean a lower weight bow but having an off tillered chrysalling heavy weight bow wont do your buddy any favors. Good luck! I hope it turns out alright.
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I did asharrow ;)
Weylin - agreed.
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Asharrow, the pic from a different angle makes it much easier to understand. When I saw the first one, it looked like you took a thin slab of the belly. I've never seen a fix like that. Seems like it would work. Thanks for posting.
Weylin, I think a lower weight bow is the way to go. I'll just have to let my brother in law know that his present will have to wait. He deserves a full weight weapon that matches his draw length as he will be using it for hunting.
Thanks to everyone for all your honest and thoughtful input. I've learned a lot. I started work on a sugar maple stave last night with the same basic design, only a little wider. My brother in law and I make maple syrup together, so maybe it was meant to be. :D
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Asharrow, the pic from a different angle makes it much easier to understand. When I saw the first one, it looked like you took a thin slab of the belly....
I have also replaced an entire belly and it is possible to cut out a section clear across the belly and up to half the thickness to make it easier to glue in a new section. In the above case or a section clear across the belly, I make the replacement part a hair longer than will fit the space, then flex the limb backward to open the space just enough to accept the new wood. That way, there's no slack to take up when it starts having to bear the compression force.
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I think your making a smart move just my opinion ,for a hunting bow it would suck to have a bow collapse on a once in a life time buck ,sugar maple is a awsome bow wood look foward to seeing that one.
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There are some things you can try but a patched bow is a patched bow. It will always be second rate, especially to you. It's not good for the ego to try and show off a bow with a big zit on it. I've patched a few and then hardly ever use them again. The patch will last longer that way though ;)
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There are some things you can try but a patched bow is a patched bow. It will always be second rate, especially to you. It's not good for the ego to try and show off a bow with a big zit on it. I've patched a few and then hardly ever use them again. The patch will last longer that way though ;)
I just took the one pictured above out and shot it a couple dozen times. It's one of my fastest bows and most stable. Nothing to do with being patched in three places, but it's a good bow.
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i was paying attention,, nice fix :)
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Asharrow, it seems like doing that fix correctly takes a fair amount of skill. Your work looks impeccable. ;)
So here's what I decided to do... baring in mind asharrow and Weylin's observation that the lower limb was bending too much, I looked hard at the full draw pics and decided they were right. I decided to take about and inch of the bottom tip, leaving the bow asymmetrical, and check the bend. Here's a picture right after I did that. I think it looks better. What do you all think?
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Whether the lower limb is bending less than it was or not, I can't tell. It looks like the tips are traveling equal distance.
Here's my advice now: If it's shooting well, shoot it. Just put a finish on it and call it done.
If we keep messing with an imperfect bow, we'll end up killing it.
Bowyers for generations have said perfection in arrows is more important than perfection in bows. I say the skill of the archer is more important than either.
Jim Davis
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how does the bow shoot,,??
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It shoots great. It pulls 50# at 30" I suppose the only worry is that it may eventually fail in the spot where the chrysal was. I think it's pretty safe on the back, as I backed it with a trusted special type of paper and put rattler skins over that. I wrapped the handle with deer hide and it even has horn overlays. Maybe I'll gift it to someone who won't use it a whole lot, although no one comes to mind.
P.S. Thanks asharrow for all the insight and advice. I'm proceeding as you suggested... this one is done! ;)