Cracks on side of bow

[High-Desert]

It's been years since I've sinew backed a bow, and recently I haven done 3 in a weeks time. Both of the wood bows developed longitudinal cracks on the side. The short 40" yew bow has pretty severe cracks, and the 54" juniper bow has pretty minor cracks. I understand what is happening, I'm not sure what I might have done to prevent this from happening. Is filling the cracks with TBIII a good fix? Am I out of luck?

Eric

[Limbwalker]

Hey man, somebody else with more experience will need to field your questions, but I am sure putting up some pictures will bring a better solution your way, if there is one. Cracks on the side I have a bad feeling about, yet to deal with one personally. Wish I could help you, put up some pictures though, if your able. Take care

[Mo_coon-catcher]

Shoot in some warmed up tgin super glue. Then clamp it shit so you have no visible seem. It should hold as long as the belly doesn't get thinned into the glue line. I've fixed a few like that. But I made them to be lighter 40# bows.

Kyle

[High-Desert]

I don't have the yew bow with the severe cracks in the house with me, but Here's a photo of the juniper cracks. I'm not sure if they can be made out in the photo, but it's a fine hairline crack. The yew bow has much worse cracks.

[High-Desert]

I'm not sure if that photo is of any help. It's not really showing up

[Limbwalker]

I took a guess and circled where I thought I saw something, you can tell me if I'm right.
https://www.dropbox.com/s/iv5xlmxrp9hvkz1/File%20Feb%2020%2C%2010%2036%2052%20PM.png?dl=0
 If it was me I'd probably do as suggested above with super glue and kee going.

[High-Desert]

Yes sir, that's it!

[Limbwalker]

So it's hard to tell how deep that is. I've read side cracks are bad news. Since I haven't dealt with one yet, I would tend to seal it w/superglue and if I was really worried lash it with silk thread or art sinew and coat that in glue as well. That's just me.

Or if it's not that deep I would rasp it out and do above if sanding/raising wasn't an option

[Redhand]

How much sinew did you use to back the yew and juniper bows?

[High-Desert]

The yew has 4 layers, a total of 1.14 ounces of sinew and the juniper has 3 layers, 1.6 ounces of sinew. It doesn't seem like an excess amount, but I'm not quite sure.

[Redhand]

I have had that happen to me with juniper.  I have put 4 layers on the juniper bow. I think the wood is do soft and with a heavy application of sinew it has quite a pull force as it dries that it rips the wood. I filled the crack with thin super glue and after I got the bow tillered out I wrapped it with sinew. I'm still shooting that bow. It don't seem to hurt the bow it just makes it ugly in a cosmetic way.

[BowEd]

Personally I had sinew delaminate a higly reflexed bow 64" long of red cedar.I have never worked juniper but have sinewed yew heartwood.I think it's a matter of how much reflex and length your bow has as to how dangerous the cracks will be.A pic of each bow might help or just stating the amount of reflex and length it has.

[Eric Krewson]

Been there, done that; not all wood is created equal, some will fail from the force of sinew drying if it lacks the structural integrity to handle the shrinkage.

In my case I used osage that showed side checks in the stave but I was able to work out of the checks during shaping. Turns out my wood was structurally weak, as the sinew cured it pulled the wood apart.

The picture shows one of many cracks that showed up in both limbs as the sinew cured.



I tried a number of fixes but found the cracks couldn't be closed and the bow was toast.

I still have the bow in my drying box 10 years later as a reminder to make firewood out of osage with side checks.

[High-Desert]

Thanks for all your help gentlemen. I will do what I can to fix these by filling and wrapping and try to avoid further sinew attempts from cracking. Maybe by applying less on the edges and more down the center.

Eric

[DC]

Could that be the reason why some people use multiple thin layers and let them dry in between?