Carbon fiber ding in shaft
- Thread starter tableroll
- Start date
After discussing with a very qualified cue maker in Maryland, he recommends that you take a small pin to make a few holes in the bottom of the ding that will serve to anchor clear epoxy in it. Your basic idea is sound, but without anchoring in the epoxy it will likely fall out with play. Also, while JB Weld certainly has many uses, it will dry gray in color and be quite noticeable. Maybe someone else has an idea as well.
DeeDeeCues
Well-known member
I'd expect anyone who knows much about CF would disagree with this qualified cuemaker.
First, drilling holes in the CF will introduce stress risers in the shaft, in a place where the integrity of the shaft is already compromised. Bad idea.
Second, 'anchoring' epoxy is likely not necessary.
Third, all other things equal, clear epoxy is weaker than epoxy with fillers, such as JB Weld. Even cellulose (basically powdered paper) will increase the strength of epoxy.
Fourth, carbon-fiber reinforced plastic (CFRP), which is what CF shafts are made of is strands of carbon fiber held together by a resin (generally an epoxy resin. Epoxy tends to stick well to epoxy, especially if the surface tension of the cured epoxy is reduced (generally by lightly sanding.
So how do you make the repair?
DeeDeeCues
Well-known member
I'd have to see it, but I would likely:
1. Lightly sand the ding to remove any possible sealers, oils, waxes, etc., and to prepare the surface for an epoxy filler.
2. Fill the ding with an epoxy with a black filler of some sort.
3. File, sand, buff the added epoxy back to flush with the rest of the shaft, disturbing the original material as little as possible.
I would do all of this only after explaining to the owner that a 'dinged' CF shaft likely means a 'cracked' CF shaft, and I would not be held accountable for the shaft in the future, as I expect the damage has compromised the structure of the shaft, and I would not be surprised to see it eventually break.
Thank you for your reply.
Graphite bedding compound, eg from WEST.
I have no experience whatsoever with CF shafts, but this filler is used to mix into epoxy when bedding bolts and such for high strength applications.
It sets quite black, and is essentially the same material as the shaft. If you over-fill the epoxy, it is also used for casting plain bearings. You might have to apply a second coat of epoxy neat after sanding and profiling the graphite after it sets, to get it to shine. Or maybe use thin superglue.
Any new process is worth experimenting with controlled quantities on scrap, and taking notes.
smt
A dinged cf shaft does not mean it is cracked. Very unlikely.
ldmitchell
Registered
Black ca glue works for me.
DeeDeeCues
Well-known member
I would argue that based on my knowledge of CF from working with it in manufacturing and engineering for a decade and a half.
You might not be able to see all the cracks and I'm not saying that it is a large crack, but I would expect to be able to find evidence of cracking with the right equipment. Small cracks grow over time.
Agree. CF is not real springy. A dent usually is indicator of failure to some degree. OP never showed a pic. Hell, if its small enough i wouldn't worry about it. Sell it cheap and get a new one.
If you want to fix it yourself, get regular general-purpose thin Super Glue and using a toothpick put a very small drop into the gouge, it sink in if it disappears very quickly add another right away then let it set for an hour so that it fully hardens then continually keep dropping a little drop into it until you build up a very small bubble above the surface of the rest of the shaft let it fully Harden. Then razor blade it as smooth as you can get very carefully maybe need to use a little bit of 600 grit than 800 + 1000 + 2000
phreaticus
Well-known member
To the OP: there is some good learning potential for some of us on this - would you mind letting us know what the final outcome is/was, if you end up trying any of the suggestions? Thx in advance & good luck.
This shit aint hard, it aint that complicated and a drop of super glue will do just fine. That may be the strongest point on the shaft! Dear god. this aint rocket science or brain surgery either. It's a shaft with a ding...DING.. Some times this stuff just gets way over thought, Like now.
Have a nice time wishing I was wrong. Come on guy's.
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DeeDeeCues
Well-known member
Please enlighten us with the science behind your statement.
I Truly apologize for my rudeness. I was having an unbelievably bad moment and certainly should have kept my mouth shut. No doubt!
To your question,
I have no science to quote at all. I've done this repair many times now with outstanding results. What i have found by doing this is that it fills the ding, bonds extremely well to the fibers and can't be felt when shooting if you make it smooth and flat with the surface. the last part is critical and touchy.
Again, Sorry you guys!
As a matter of fact, I love that you all dive into the science and physics of this stuff. I get to learn a ton of interesting things without doing the work to research it. I've gained greatly from that. Thank you, and please don't let my little moment being a total jackass make you think otherwise.
Jay
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DeeDeeCues
Well-known member
I didn't think you were rude.
In all actuality, filling with super glue may be fine. Personally I'd contend that epoxy would be better.
The problem is that a ding could easily be tearing fibers and compromising integrity. I'd play it safe and warn my customer before the repair.
Have a better day!
Thank you. I had a MUCH better day. Your response was a big part of that.