Gunsmithing Filling unwanted cutouts in CF stocks

[317millhand]

So, what type of material would be used to fill an un needed bolt release cutout in CF stock? There isnt a gunsmith in the country with the time to do ANY stock work without a 4 month wait, so I'll attempt this myself. Ive heard everything from Devcon, gorilla glue, minute mend, to JB weld. I'm just worried about it breaking out.

 

[sgtsmmiii]

I've had good luck with Devcon - none have ever popped out on the couple I have done. I'd use it again.

 

[Snuby642]

Marine tex is tough.

Might consider blending in the paint and just rocking it.

 

[shoobe01]

I wouldn't use epoxy alone. Cut a piece of something and glue that in. Many plastics will do nicely, but if happier with metal, do aluminum. Not wood or any composite that can absorb water (e.g. glass fiber).

I'd get a plastic specific epoxy, and if you can swing a couple extra dollars and a few days of drying, G-Flex is probably best for this. It is used for boats and things like that made of GFRP and CFRP so is formulated to stick and it never cures rock hard, but maintains flexibility along the lines of the stock materials. Even when dropped, or gets very hot or cold, it won't crack off.

If you want to fill with epoxy alone, I still would try G-Flex, but whatever epoxy you use, fill the spaces with microballoons. Easily available in small quantities for model making. They are tiny, tiny, tiny glass beads that are used in this case to add volume, but they stick perfectly to the glue so reduce the strength not at all. (If wondering, they are the same thing that makes retroreflective signs work, like ScotchLite, but they won't make the stock shiny the way you are using them).

 

[Mr.BR]

Have spent past 25+ years doing CF composite parts and also made bunch of CF stocks i would carefuly dremel out any fill that is not high density and use epoxy adhesive,the most important is the material preparation so that adhesive can make a solid connection. IF you just want to reinforce the cut Just about any epoxy will do ,but if you want to reconstruct the material cut away its best to use some substrate to fill the space ,can be even piece of hardwood ,but better still ,fiberglass or carbon (buy a rod or plate used in RC) . Epoxy makes a mechanical bond not chemical one so preparation is key . But judging the size of the cut you could likely get away by using a highly filed adhesive .

As epoxy is not very UV stable you can finish it with some paint on a swab to make a similar patern that is used on the stock.

 

[GH41]

I would leave it alone if the core isn't exposed if you care what the repair will look like. This is the classic case of the cure being worse than the disease. The problem is.. How do you blend in the repair without damaging the surrounding texture and paint??

 

[BuildItYourSelf]

Carbon is cheap these days. You could carbon in a carbon fiber plate. Or lay your own.
I would recommend waxing the hole you intend to fill (so nothing sticks) then filling with bondo or similar with the purpose of smoothing to shape.
Then make a mold with bondo or fiberglass.
Then clean, sand and prep the hole. Lay the filler meterial in and lastly lay the finish layers on the bottom that will be the goo looking part. Drop it in the mold. Clamp it down and press the filler meterial against the mold and wait.

If at least you want to use carbon I have a coffee can full of scraps I cut up and break apart. So it's basically loose ribbins anywhere from an inch to 6 inches long. Just mix the epoxy and then start laying in the fibers and continue pressing the epoxy out.

 

[Ledzep]

Rough up the bottom of the existing feature with 60 grit paper or a very coarse file, then clean it with hot dawn water, rinse, let dry. Then use gas tank repair putty (the tubes you kneed to mix the inner and outer materials). It cures fairly quickly, best to make it a little bigger than it needs to be (over-fill) then file it back down.

Then I'd go find some hobby paint, or ask Manners what they use and try to match that brown as close as possible and sponge over the area.

 

[Mr.BR]

I would leave it alone if the core isn't exposed if you care what the repair will look like. This is the classic case of the cure being worse than the disease. The problem is.. How do you blend in the repair without damaging the surrounding texture and paint??

True folks without any experience in composites can and often do turn these kind of issues into much bigger ones . Have encountered bad DIY fixes of composite parts as long as i can remember and fixing the fix turned out to be the biggert part of the job in most cases.

 

[dinc]

Listen to Mr.BR, you're going to have to rough up where you want the epoxy to stick. Even dig a little notch in on the front and back so the patch will have a mechanical lock. Go to WallyMart auto section or a home center and get some fiberglass cloth and JB Weld gray. Cut up, chop, little teeny pieces, a couple of ounces of fiberglass and put it into the JB when mixing, end up with a nice goo full of glass fibers. You've already taped up the outside of the notch, lay the stock on it's side and fill the void with the glass slurry. The next day you might have to sand it down a little depending on how tight the tape was. Then the tough part is trying to match the paint.

 

[317millhand]

Thanks for all the info. I'll see how it goes

 

[spife7980]

Manners wont do it for you? Or is that apart of the four month wait as well?