Trad Gang

Main Boards => The Bowyer's Bench => Topic started by: J. Cook on November 30, 2018, 01:21:56 PM

Title: How do you repair cracks in the glass from overtightening limb bolts?
Post by: J. Cook on November 30, 2018, 01:21:56 PM

Hi guys - I've got a TD recurve with some linear cracks in the glass that go through the bolt holes.  They appear to be a result of overtightening the TD bolts.  I'm going to do a complete refinish on this bow and would like to repair those cracks as well.  My question to you guys is what's the best method for doing that?  Do I just overlay with superglue after I get the finish off and then sand that down smooth before refinishing, or is there a better alternative.

Please be detailed in your response as to how to repair those cracks.  These do appear to be superficial only, but I want to fix them while I'm already re-finishing the bow.

I tried searching and didn't get exactly what I was looking for.

Thanks in advance!!!

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Flem on November 30, 2018, 03:12:47 PM

Well, it's a bit difficult to give a detailed response to your issue without some good pictures. I'll take a stab at it anyhow. With the old finish gone, get some dummy bolts, wax them and thread them in the holes. Mix up some low viscosity epoxy, like Smooth-On Epoxamite, or System Three Clear Coat. Gently heat up the area to be repaired with a heat gun and pour some epoxy on. Gently heat up the epoxy to help it flow into the crack and then let it cure at room temp. Sand the repair flat after curing, then finish. Good luck! :thumbsup:

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Mark R on November 30, 2018, 03:39:18 PM

You could overlay with some nice wood veneer using smooth on jmho.

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Crooked Stic on December 01, 2018, 10:46:16 PM

I am thinking overlays with smooth on.

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Al Dean on December 02, 2018, 09:13:02 AM

Stop drill the crack, then proceed as you wish.

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: kennym on December 02, 2018, 09:25:25 AM

I was thinking overlay it also, but if you can get the glue to work to your satisfaction, I  do like no overlays. So try glue first and if you don't like the result, overlay it .

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: monterey on December 02, 2018, 11:45:25 AM

Do the cracks extend into the wood?  Can you see cracks in the wood at the butt end of the limbs?

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Tim Finley on December 02, 2018, 12:39:07 PM

Glue wont work the cracks will keep going eventually way down the limb . You need to overlay that stops the crack, moisture, humidity will cause the cracks to travel . Ive tried drilling holes in the end of the cracks but they just go on though .
  Its mostly caused by moisture getting in through the bolt holes they aren't coated good or the threads wore off the finish . If you have uls glass it normally wont happen .

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Flem on December 02, 2018, 02:49:35 PM

I think the Op lost interest, or maybe he's trying to figure out how to post pictures. :smileystooges:

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: J. Cook on December 05, 2018, 10:54:54 PM

Hi guys definitely haven't lost interest - had to go out of town unexpectedly for work.  The cracks are on both belly and back.  Not in the wood or limb cores at all that I can tell. 

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Crooked Stic on December 06, 2018, 09:34:35 AM

Can you feel them from the outside of the glass? Looks like stress lines being it is on the belly also.

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Flem on December 06, 2018, 11:47:52 AM

My recommendations are worthless, now that I see the pictures. Looks like the problem is more extensive than just over tightening the bolts. Pinstripe those limbs, or paint them to look like corduroy.

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Tim Finley on December 06, 2018, 08:04:15 PM

Ya its too late for that bow !!!

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: J. Cook on December 06, 2018, 10:24:46 PM

Quote from: Tim Finley on December 06, 2018, 08:04:15 PM

Ya its too late for that bow !!!

Explain?  Is the bow beyond repairable and shouldn't be shot, or you mean it's just too late to truly "fix" the glass? 

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Crooked Stic on December 07, 2018, 08:36:34 AM

Repair it with new limbs.

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Flem on December 07, 2018, 10:32:10 AM

I think I would shoot it, but not worry about making those limbs pretty again.

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Mark R on December 08, 2018, 12:33:28 AM

Belly and back look like stress cracks for what ever reason, they may continue to grow, use at your own risk, the glass is the strongest part of the limb if it fails nothing there to save it, see if you can get new limbs jmho.

Title: Re: How do you repair cracks in the glass from overtightening limb bolts?
Post by: Pat B on December 08, 2018, 11:57:14 AM

Could it be faulty glass. I don't build glass bows so it's just a thought.   :dunno: