best way to make a pvc air chamber

Major Collins · Mon May 09, 2011 11:00 pm

as we all know pvc would be one of the weaker materials for pneumatic spudgun use ,but what is the ideal way to make a pvc air chamber.
A pipe chamber with a bushing and glued on/in cap or plug?

(for 100 to 140 psi)

Crna Legija · Mon May 09, 2011 11:05 pm

pressure rated pipe and fittings glued together with PVC glue and primer.

this has to be the dumbs question you have made.

Major Collins · Mon May 09, 2011 11:22 pm

other people have input aswell, one way might be better than another -
im just collecting information

Technician1002 · Mon May 09, 2011 11:30 pm

What diameter are you planning on using? I don't recommend using above 100 PSI in PVC chambers larger than 2 inch due to the failure mode. Failure in a 4 inch chamber above 100 PSI can be lethal.

Most big box hardware stores don't have pressure rated fittings larger than 2 inch. A 3 or 4 inch PVC part is most likely DWV and not rated for pressure.

Major Collins · Tue May 10, 2011 12:18 am

i would like it to be either 50 mm or 40 mm so 2 inches and smaller will be the diameters i will be working with

by the way is it bad to glue pipes that fit into each other to just make reducers? eg

black is 40mm and red is 40 mm cap with end cut off and green is the next diameter that fits on

Crna Legija · Tue May 10, 2011 2:51 am

you should measure the socket depth of the same sized pressure rated fittings and glue it in a bit deeper than that. should be fine.

shardbearer · Tue May 10, 2011 3:33 am

I wish our pipe nested perfectly like that and all the couplers had nice round numbers for the OD. Hell, if anything was logical in this imperial system it would be a miracle.

Technician1002 · Tue May 10, 2011 4:23 am

From experiance there are issues with trying to nest pipe. An earlier version of my Mouse Musket had trouble with leaks. The issue is the nested layers have no taper, so they don't go together tight. When the solvent glue dries and shrinks, it leaves leaks. Proper fittings are slightly tapered inside.

The Mouse Musket does not leak because I ran a small bead of caulk at the bottom of the home made socket in the chamber breech. The Dragon with it's home made bells also has a caulk line for a seal in case the glue does not provide the 100% seal.

1.5 inch female adaptor nested inside a 2 inch pipe.

Major Collins · Tue May 10, 2011 6:52 am

wow a plug, there are none that are pvc here in australia or that i have seen.
I will have to probably try 5 differnt shops before i find one

So is "nesting" the term whenstacking pvc layers together like i mentioned in the previous thread?

Meat · Tue May 10, 2011 11:20 pm

Yes thats what nesting is. Nesting (at least with the pipe I use) doesn't even give as good as a seal than using real couplers for me, but your pipe diameters may work well. If you can try to get couplers and real fittings instead, but nesting would work as long as there is enough material being cemented (not too many holes) for the cannon not to burst.