Cracks appearing on limb

Fred_K

New member
I noticed the other day that some tiny cracks have appeared on the back side of the top limb (G3) on one of my bows. There are three cracks perpendicular to the limb, starting at the edge, which are about 5 mm long and there are two bubbles, roughly 5 mm in diameter, in the middle which have cracked open with tiny holes. All of this is just past the fade out. The cracks don't seem very deep and, to my untrained eye, it looks like it's only in the paint layer. Are there any good and simple techniques for patching them up? Epoxy, super glue or something like clear nail varnish perhaps? Or is this a sign of imminent catastrophic limb failure?

Thanks for your input,
Fred
 


Midnight

New member
I am absolutely no expert in archery by any means but I know a bit about basic engineering and that sounds very much like stress fractures.

The outer laminate would provide structural integrity to allow the weight to be kept down on the parts of the limbs that provide the force to project the arrow.

I would highly recommend that you do NOT string the bow and absolutely do not draw it.

Take the limb to your local expert who will be able to determine the extent of the damage.
 


Martin Heelis

New member
Ironman
Perhaps you could post some pictures / links to pictures on here? Alternatively, take them to a shop and ask them to have a look.
 


Del the Cat

Well-known member
There are two possibilities.
1. It's cosmetic, in the surface finish, gel coat etc. In which case it doesn't matter a jot, but sealing with some compatible varnish, clue etc will help stop water ingress.
2. It's actually in the lamination (unlikely) in which case it is beyond repair (IMO) as it is running across the limb..
This is why (IMO) paint finishes etc are more hinderance than help... they stop you seeing what is actually going on, and they generally aren't designed to be flexed, which is why they are liable to crack.
Del
 


Fred_K

New member
There are two possibilities.
1. It's cosmetic, in the surface finish, gel coat etc. In which case it doesn't matter a jot, but sealing with some compatible varnish, clue etc will help stop water ingress.
2. It's actually in the lamination (unlikely) in which case it is beyond repair (IMO) as it is running across the limb..
This is why (IMO) paint finishes etc are more hinderance than help... they stop you seeing what is actually going on, and they generally aren't designed to be flexed, which is why they are liable to crack.
Del
I've had a chance to look more closely at the limb with a magnifying glass, and take some pictures through it, and it seems as though it only is the surface finish that has cracked. These cracks are, as can be seen in the pictures, originating near a spot which has earlier been knocked against something but I noticed there are also a few more small ones in other places.
Assuming that it's case 1, which would be the best kind of varnish to use? Does anyone have experience with these kinds of fixes?
In case it's case 2, and someone recognizes these cracks as symptoms thereof (I seem to remember having heard stories of G3's delaminating and someone might have seen some just before blowing up), please let me know and I might avoid being smacked in the face..

Cheers,
Fred

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Del the Cat

Well-known member
dunno about those finishes, but I've just filled some longitudinal cracks on an expensive piece of Pacific Yew with very low viscosity superglue. it really wicks in there and fills nicely. It's used a lot by bowyers these days. I'd think it would be a good bet as it will get right in there rather than just 'papering over the cracks'
Del
I found some good stuff on line at a V good price, postage would have been more than the glue but they had a buy 2 get one free. Prob not much use to you unless you have a whole bunch of anoying schoolkids to glue together or somesuch.
be sure to get low viscosity, ultra thin etc.
 


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