ERC ELB belly patch

[AH]

Hi,
Recently finished this Hickory backed ERC. It's 50 @ 28 and 72", also my first time working with ERC. There's a problematic knot, which developed a crack after a hundred arrows. the crack also extends about an inch and a half or so up the limb from the knot, in the "swirl" of grain surrounding the knot (i've drawn a red line to show where it is in the pics). After consulting with someone with more experience than me with this wood, i decided to keep shooting it as it seemed stable; but after 200 or so more arrows today it seems like the area has gotten worse and has formed a slight hinge.

So it seems the logical solution to would be to patch the belly. I've never done this and am a little apprehensive about how to do it. How long should these be and what would be the steps to approaching it? Also, I laminated this bow with TBIII as it's the only glue i have right now--would that hold for the belly patch? or could perhaps cyanocrylate?

Would really appreciate any input, I really like this bow. Overall impressed with how ERC performs but seems i didn't leave enough meat around this knot. Thanks!!

Pics:
https://imgur.com/a/DXjXzO7

[DC]

Go to this site and do a search for "patch" or "belly patch" or maybe del will chime in with a direct link.
http://bowyersdiary.blogspot.com/

[bownarra]

The best way to fix this bow is to start another one taking the lessons learnt from this one
Saying that you can gain good experience trying belly patching on this bow.
If you try to fix it then the patch needs to be quite long out of flawless wood and glued with an epoxy like EA40. Do NOT use CA! It is really only any good for tip overlays, inlays and filling cracks (thin stuff). TB111 would be prone to joint creep in this application.

[Del the cat]

Here are a couple of examples:-
https://bowyersdiary.blogspot.com/2019/09/elm-tribulations.html
https://bowyersdiary.blogspot.com/2017/01/two-part-knot-patch.html
My advice is to take out a long scoop (at least 4") keeping it flat across the patch but curved along it's length (like flexing a steel rule). Tke as long as necessary to get a good fit, checking with the light behind it, a slight gap in the centre is ok as that will hep the ends press down when it's clamped (or rubber strapped). Make it fairly close to final size so that there is some flex to help a good fit.
If it looks like you will have to go too deep, (say there is rot or somesuch), leave the long shallow scoop and take out a shorter one at the knot and fill the problem area, once that's filled, clean your original long scoop and do the patch.
I did one on a warbow with two nasty deep chrysals which went deep, I did two deep short patches and a long one over the top of both.
https://bowyersdiary.blogspot.com/2017/05/a-warbow-repair.html
Del
PS. One bowyer was asking a mate of mine about belly patches 'cos he "couldn't get 'em to work". My mate said "I've watched Del do one and I was surprised at the amount of time he took to get a good fit, back and forth on the belt sander, checking and adjusting".
the bloke said "I havn't got time to mess about like that" ... yes, and that's why his belly patches don't work! 

[Eric Krewson]

I like Del's multipatch idea, I have done several half moon patches, one on a very narrow osage ELB didn't make it, one on a flat belly osage bow lasted a couple of years before it cracked out. This was back when urac glue was available, urac was unmatched in its gap filling and holding ability.

[bradsmith2010]

u guys are amazing that can do that,,

[mmattockx]

I just had to deal with a knot that was under the surface of the board when I started. It appeared as I removed wood to get to final limb dimensions. I soaked it with CA and it caused no trouble during tillering, but started to hinge maybe 150 shots in. I rasped a groove into the limb and filled it with a scrap piece of maple (the bow is maple). First time trying this and it is holding so far after another 100+ shots since the repair. I used plain old yellow wood glue for the patch.

The knot that caused the trouble:




The patch after being rough shaped:





Mark