SpudFiles

i have been look around and all the pvc i can find is dwv fittings and cellular core pipe. any suggestions? how bad would it be to use those?

It depends, I strongly dislike PVC due to it's fragmentation characteristics, in a spray & pray it "might" hold out, if you get a near perfect fueling ratio at some point it could give you many piercings, or it may not.

Try a plumbing supplier or agricultural supply store, they have a very good range sometimes. It wouldn't hurt to post an approximate location, just so we can help you better.

I can get 6 inch PN12 fittings and pipe at my local ag store, so such fittings are available, just a matter of looking in the right places.

A small ag store near me has the largest array of steel SCH 40 pipe I've seen, half the price of a hardware store too.

Where are you looking, first of all? If you can't find the pipe and fittings you need at a local-type hardware store try a big-box place, and if you can't find them there check out some irrigation stores. You may have to do some running around.

For a combustion, DWV solid core pipe and fittings will be acceptable. For a pneumatic, you must use pressure rated pipe and fittings. Your location would help a lot.

Is the Cellular Core stuff PVC or ABS? If it is ABS the testing I have done can be seen in the thread in my sig below. I know.. Shameless self promotion...

Try here.

i found some pressure rated pvc and pressure rated couplings. the couplings are quite expensive so i think i will use those for the elbows and use dwv for the simple couplings not receiving much stress

It is only as strong as it's weakest part.

He's referring to the stress placed on the elbows due to recoil when firing, not pressure.

actually i was thinking that because the majority of a simple coupling's area is reinforced with the pipe it is attached to there is a fractional area on each coupling actually receiving any pressure. in contrary on the elbow they have a larger area not directly reinforced by the pipe therefore more potential area subjected to the pressure generated when firing.

There is some truth in that but it is just as unsafe in my mind. Doesn't matter how much is exposed... what matters is that it is exposed.

Cell core pipe is fine for even an advanced combustion gun, as long as it is at 1X. It'll handle the ~130 PSIG max pressure that a jammed round would produce.