SpudFiles

I came to thinking, for things like a hybrid piston valve or other complex valves or custom parts, it is a lot easier to make them out of PVC instead of metal (unless you have a milling machine, of course). Also, PVC is significantly cheaper than metal pipe. However, it can not withstand higher pressures. I was wondering if a way around this would be to layer a PVC pipe or fitting in several thick layers of epoxy hardened kevlar or carbon fiber. Of course, it may be cheaper to buy metal pipe anyway, and I'm not saying I am actually going to do this, I have lots of metal pipes, but it would be pretty awesome to get a PVC pipe to withstand pressures higher than 125psi.

kjjohn wrote: it would be pretty awesome to get a PVC pipe to withstand pressures higher than 125psi.

Well... Regular 1" sch40 PVC has a pressure rating of 450 psi. I read somewhere that the actual burst pressure is over 1000...

kjjohn wrote:it would be pretty awesome to get a PVC pipe to withstand pressures higher than 125psi.

http://www.engineeringtoolbox.com/pvc-c ... d_796.html

Carbon/ Kevlar and Epoxy are more expensive than metal of practically any sort.

well, i once saw a "just for fun" project where a couple guys made a (relatively) HPA tank layering carbon fiber around, of all thing, a beer can. they (said they) tested it to about 2000psi. if those are actual numbers, it'd work for PVC too. Hawkeye is right, metal would be cheaper, but PVC/Carbon fiber would be a lot lighter

Extremely pointless to every degree. For the price of carbon fibre of kevlar you could easily have made your gun from stainless steel. And what about threaded fittings anyway?

If you absolutely insist on covering your PVC in something, buy a can of fiberglass resin, some catalyst and fibreglass stands.

Just make the gun out of plumbing parts, you can build almost any type of gun using them, no welder. Covering PVC with kevlar or carbon fibre will really just prevent shrapnel from exploding out of it, not fracturing, as the PVC may crack and leak, and just get caught by the covering.

well there are applications of wrapping for projects that require minimum weight such as planes or possibly airsoft/flour/paint grenades and bombs that have to be thrown

I'm not sure if it would be a good idea to wrap pvc, pvc tends to be more on the brittle side when handling pressure, so does pvc even strain enough before reaching yeild strength to make the wrapping work?

Fiberglass would be much cheeper than kevlar and carbon fiber. If you wrapped PVC in fiberglass it would definitally increase the PVC's stength.

Carbon fiber cloth and thread are fairly available to hobbyists at less than outrageous prices. Check out ebay. It may end up costing a bit, but if it actually gives a considerable increase in strength it could produce a cannon with excellent strength/weight ratio. I think it would be worth it. Not only would it provide a good strength/weight ratio but it would also allow you to use widely available low pressure fittings, modify or customize them in ways that would ordinarily "void" the pressure rating, then once it's all together just wrap it in CF and epoxy to reinforce.

Carbon fiber cloth and thread are fairly available to hobbyists at less than outrageous prices. Check out ebay. It may end up costing a bit, but if it actually gives a considerable increase in strength it could produce a cannon with excellent strength/weight ratio. I think it would be worth it. Not only would it provide a good strength/weight ratio but it would also allow you to use widely available low pressure fittings, modify or customize them in ways that would ordinarily "void" the pressure rating, then once it's all together just wrap it in CF and epoxy to reinforce.

My thoughts exactly. You could make a high-mix hybrid completely out of PVC, or machine high pressure parts from plastics.

I've ordered some carbon fiber cloth and epoxy off ebay to try this with.

Carbon fiber

Epoxy

Plans are still in the works but I'll post a link in this thread once some more progress has been made.

EDIT: Accidently linked to medium viscocity, I ordered low viscocity epoxy. Link is now corrected

PVC is already heavy as hell. By the time you get it all covered, its going to be a real tanker to carry around. PVC cannons weigh a ton because you are stuck with thick walls and super heavy fittings, so by the time you cover it you might as well have used aluminum pipe and fittings. Plus, I think the PVC would just shatter anyway and you'd have a non working fiber glass shell of a cannon.

I agree with Moonbog, I mean really, in order for the the carbon fiber to have any effect, the PVC would have to expand... and byt the time that happens, you have shrapnel. With a broken inner shell, you have a useless heap of crap that I don't think has the ability to hold any pressure... but I really hope you prove me wrong!

Slauma wrote:Carbon fiber

ooh, interesting...

I've been wanting to use something similar ever since I got my Daystate Airstream silencer...