sch 120

[tyguy2000]

I am considering making my second spud gun sometime soon. My first was a rather expensive 8 foot pneumatic with a 2" sprinkler valve. To save cash and space I am thinking about making a short coaxial run at extremely high pressure. I have googled sch 120 and understand that it exists but I have never seen it or read about it on these forms. What are your experiences with it? Is it hard to find? Expensive? Not worth the effort?

[MrCrowley]

Correct, hard to find, expensive and not worth it, what pressures are you looking at running this thing?

[tyguy2000]

I am considering around 300 psi. But I also would like to stick to a cannon type design with a chamber of about 6 inches. Only sch 120 can hold that pressure with that diameter.

[thespeedycicada]

Steel or aluminum is a much much much much much much better choice.

[Lentamentalisk]

make a longer skinnier chamber, as smaller pipes have greater strength. Also, make sure to think through your valve, since most commercial pistons and QEVs can only hold about 150psi

[thespeedycicada]

which is why piston valves are homemade to hold the highest pressure i dont think i hve ever heard of a commercial piston valve i thought they were all handmade.

[williamfeldmann]

Yeah any metal is going to be a better choice and possibly even cheaper depending on where you get your pipe.

You would be the best off building a piston or diaphram valve. They will hold up better than a purchased valve.

[iknowmy3tables]

put a tee on the coaxle body and build up more chammber space that way

[DYI]

Why use SCH 120 PVC when SCH 40 steel is stronger, cheaper, and easier to find?

[tyguy2000]

Interesting. And yes, I am planning on building a epoxy piston valve based on the guide in the how-to forum. It seems like the best way to make a good piston considering I have no machining capabilities. I suppose I will go with long and skinny sch 40 or 80 then because like I don't have any tools to to work metal or experience with it.

Thx for your help.

[DYI]

You don't really need tools to use metal pipe, all you need is teflon tape and a pipe wrench or two. Metal piston valves can also be built without special tools (check out Brian the Brain's cannons)