Author Topic: Is this limb totaled? (Read 2686 times)

buckeyebowhunter · « **on:** May 25, 2019, 12:23:29 PM »

Made up a new set of limbs and after about 50 shots these guys showed up after i took her down to apply wax to the limb pads i noticed them? Is the limb done for? And what the heck would cause them in such a short time? I had an old black widow with similar cracks around the bolt holes but they were not quite as long and the bow was 20 years old. This one is about a week old. Thanks guys

Wolftrail · « **Reply #1 on:** May 25, 2019, 12:28:06 PM »

Does the crack go thru all the way. If not I would be inclined to repair it, groove out the crack and use some epoxy or glass to repair it. Its worth a try.

Flem · « **Reply #2 on:** May 25, 2019, 01:42:11 PM »

That sucks! I'd want to know what caused that before I bothered to try to fix it.
Can you put some kind of transferable marking on the riser to see if you have uneven contact?

buckeyebowhunter · « **Reply #3 on:** May 25, 2019, 01:50:59 PM »

Flem to answer your question I'd say there is some uneven contact between the limbs and riser fades but to be honest the lower limb has the same angle and it seems unharmed. I may end up trying ULS on my next build. I believe this is UL glass from bingham kits. (This is just an educated guess) i honestly don't know what type of glass bingham sends in the kits i had never thought about it or bothered to ask at the time.

Bvas · « **Reply #4 on:** May 25, 2019, 02:15:22 PM »

I’m not a takedown guy, but could you epoxy a thin piece of phenolic to the limb to keep the crack from traveling any further?

buckeyebowhunter · « **Reply #5 on:** May 25, 2019, 02:16:33 PM »

Brad i honestly thought the same thing. But would it actually stop the cracks? Or would they travel on around it.

kennym · « **Reply #6 on:** May 25, 2019, 02:40:42 PM »

A lot of cracks like that are from tightening the limb bolts with a gorilla wrench or no finish in bolt and pin holes allowing moisture to swell the wedge and crack the glass.

I had one crack before I ever bolted to the bow same way...

I’d go with brads idea and keep your eye on it. Be sure to do same to both limbs...

buckeyebowhunter · « **Reply #7 on:** May 25, 2019, 03:05:45 PM »

Thanks guys. On with the phenolic

jess stuart · « **Reply #8 on:** May 25, 2019, 03:26:14 PM »

I agree overlay and keep shooting it. Insect the bolt holes in the limb and see if the finish is worn. I always try to add some wax to the holes each time I take the bow down. Moisture has a way of finding it's way in.

Crooked Stic · « **Reply #9 on:** May 25, 2019, 06:03:00 PM »

I would flsat block sand that area. make sure it is flat. being the cracks are at the torn edge of the glass where it was torn by the drill bit it may be stressed by the bolt. And yeah overlay it with phenolic or glass.

TradBowyer · « **Reply #10 on:** May 25, 2019, 07:14:06 PM »

your fine as long as the cracks dont go past the pin hole into the working limb.

buckeyebowhunter · « **Reply #11 on:** May 25, 2019, 07:31:13 PM »

Very much appreciate the replies fellas

Bow Bender · « **Reply #12 on:** May 26, 2019, 02:11:16 AM »

One trick to keep the crack from traveling farther is to drill a small hole through the glass at the end of the crack and fill it with ca or epoxy before laminating over it.

Crooked Stic · « **Reply #13 on:** May 26, 2019, 06:47:01 AM »

I agree if you drill a good clean hole. But if you notice those cracks have traveled out of the already drilled hole and appears to have started where the glass is torn. I always use a 45 degree stone to chamfer the drilled holes.

buckeyebowhunter · « **Reply #14 on:** May 26, 2019, 07:28:01 AM »

Stic i used the stone bit that binghams sells. But i think the original bit tore it so bad that the stone bit only did so much if you know what I'm trying to say

Flem · « **Reply #15 on:** May 26, 2019, 07:51:49 AM »

Curious what type of bit you guy's use to drill the fiberglass?
I would guess an abrasive core bit for glass and ceramics?

Shredd · « **Reply #16 on:** May 26, 2019, 08:38:26 AM »

It could be what Kenny said or it could be caused by the bolt and pin... I can't tell in the pic, but do you have a champher or a counter sink through the glass in the hole so that the bolt or pin does not come in contact with the glass... Stress on the glass from the bolt and pin could also be the problem... It looks like like that in the pin area...

buckeyebowhunter · « **Reply #17 on:** May 26, 2019, 10:22:51 AM »

Shredd that is the inside of the limb so the only thing is contacting is the fade out on the riser. Flem i just used a regular wood bit for the original hole then the counter sink was done with the stone(deburring) bit that bingham sells.

Flem · « **Reply #18 on:** May 26, 2019, 10:39:03 AM »

So those cracks are from chips around the edge of the hole, caused by the wood bit. Kind of like getting a chip in your windshield, you know it's going to spider.
I think I would invest in a good diamond lip core bit.

buckeyebowhunter · « **Reply #19 on:** May 26, 2019, 11:08:26 AM »

Flem thanks for the tip. I did not run into this issue on the last set of limbs though

i used the exact same bit.

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Author Topic: Is this limb totaled? (Read 2686 times)

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