Epoxy barrel

[daccel]

Has anyone made an epoxy barrel before?

It might be a way to get a rifled barrel larger than commercial airgun barrels. You could wrap narrow tape around a rod to whatever twist and layer it if necessary to make deep enough grooves. Or use wire with tape in between if the epoxy wasn't hard enough for your ammo. Then center the rod in a pipe and cast the epoxy around it, hammer the rod out and clean out the tape.

Would the epoxy stand up to a lead pellet?

[blind909]

1. I dont think anyone has made an epoxy barrel, and 2. Yes, it should stand up to a lead pellet.

[Velocity]

I think making the epoxy barrel would be pretty difficult, certainly more difficult than just buying a length of PVC or the like. I guess you could cast it between two lengths of pipe...but it would still be messy and difficult. It would also have to be of a short diameter as well as a short length.

[Lentamentalisk]

I just have my doubts that it would be consistent enough. If you do do this, you should leave it in the casting pipe for strength.

[daccel]

The advantage of this over rifled pvc is that it's much harder, allowing you to use ammo that would strip out or not engage the pvc rifling.

You could also do an initial thin coat before putting it in the casting pipe to eliminate bubbles or irregularities along the rifling, or even do a fiberglass or carbon fiber wrap instead of casting.

[jackssmirkingrevenge]

I contemplated this, however in terms of hardness I think it would be disappointing and wear out pretty quickly. It's probably more worthwhile sourcing a barrel from an air rifle for small calibres.

For a large calibre spud barrel however, I see no reason why it wouldn't be perfect if used in conjuntion with carbon fibre or similar. It would get a little expensive though...

[jimmy101]

You'll have to get the mandrel twist rate perfectly consistent in order to unscrew the mandrel from the finished barrel. Get the pitch a little inconsistent and you won't be able to unscrew it.

Epoxy really isn't all that hard, even compared to lead. I would suspect that the rifling will wear pretty quickly.

[i-will]

i say go for it. i was planning on doing a fiberglass wrap for an airsoft barrel one day and am still lookin forward to it.

if u got the time and money do it. i kinda agree with Lentamentalisk about leaving the cast pipe over it but not for strength. leave it on so it'll be easy to fit on standard fittings. u don't wanna put all that work in and only be able to use it on one project.

it should be strong enough though. i made a paper wrap barrel a few months ago for an airsort shooter and i still use it.

but if u want it to last forever do a fiberglass or carbon fiber wrap.

[daccel]

The way I was thinking of doing it you wouldn't have to unscrew the mandrel because you're not cutting the rifling into it, but building it up with something that isn't permanently fixed to it, like tape or wire with tape or wax or something in between. It can just be pushed straight out and then the layer cleaned out with heat or a solvent.

I think the diagram I have would work, but it would be difficult to get a consistent layer between the wires. Maybe paint that wouldn't stick very well to the steel or epoxy?

If the wire is exposed only 1/3 or so and you sand the back of it I think it should stay fixed in the epoxy. But maybe round rifling wouldn't be enough to engage the projectile.

[jonnyboy]

I would work but if you have a tight fit with your projectile it will wear away the barrel and make it useless. I think just buying a barrel would be far more effective and last longer than one made from epoxy.

[jackssmirkingrevenge]

Interesting... what if you used a soft-ish mandrel, and wrappd the wire tightly so that it bites into the mandrel...

[daccel]

I agree that for .177, .22 or similar it would make sense to buy a barrel. But this would allow you to use 9mm or .50 pellets, or larger if you're launching something else.

Soft eh...something like a pool noodle?

What about a rubber hose over a pipe. If that wasn't soft enough you could do a layer of that foam weatherstripping tape that is adhesive on one side, and rubber over that, because the foam wouldn't be smooth enough by itself.

If you put a lubricant between the rubber and the core, it should be possible to pull out in two stages, even with the wire tightly wound.

[jackssmirkingrevenge]

I agree that for .177, .22 or similar it would make sense to buy a barrel. But this would allow you to use 9mm or .50 pellets, or larger if you're launching something else.

That probably wouldn't work on such a small scale. I would think this method would be practical for say a 1 inch barrel launching starch based projectiles, but on a finger level it would wear out quickly anyway.

Here's a thought, how about mounting the barrel on a couple of bearings and hooking it up to a motor

[Lentamentalisk]

Wow, that is almost a decent idea... gear a dremel to a barrel, and you have instant rifiling. You don't even need grooves if you get it spinning beforehand... ignoring the fact that you could never get it stable, and you could never get an airtight seal, that is nearly an idea worth the cost of the firing squad. Jokes.

I actually like that idea, as impractical as it may be. The inspired (read starving) inventor in me is saying 'ooooh! that would be awesome', lets do it, but the engineer is saying 'shut up you idiot, that would never work'.

[jackssmirkingrevenge]

It would work, provided there's enough friction between the projectile and the barrel. There are many examples of rotating airtight seals in modern engineering, so there's no doubt it can be done. Question is, is it worth it?