Is Schedule 40 PVC safe to use?

territorialpissings · Thu Jul 03, 2008 12:15 pm

I've heard from numerous sites that schedule 40 will burst. All I've made is a basic combustion, 2' of 4" for the chamber and 5' of 2" for the bore. Neither Menards nor Home Depot carried SCH 80 therefore I just went with the 40 assuming that with my basic gun it should be fine. Did I assume correctly or am I going to get plastic lodged in my neck?

bigbob12345 · Thu Jul 03, 2008 12:23 pm

Is it pressure rated or not?
If its pressure rated then you have absolutely nothing to worry about with a combustion(which I am assuming is a spray and pray).
If the pipe or fittings say nsf-pw on them it is pressure rated, and if they nsf-dwv on them it will blow up in your face spraying shrapnel in all directions.

territorialpissings · Thu Jul 03, 2008 12:29 pm

nuts, the bore is NSF-PW and the chamber is NSF-DWV. I hope to god I dont need to find new pipe, do I? I dont want to shell out more money for new fittings, etc.

Could I just attach some speaker wire to the ignition and use my garage as a bunker?

FishBoy · Thu Jul 03, 2008 1:16 pm

my guess is that you'd be ok if it's just a spray and pray, but i'd ask some of the more nowing people on here

Pilgrimman · Thu Jul 03, 2008 1:46 pm

Look for the pressure rating. If it says at any point "xxx psi" you will be okay. Even if it is not rated for pressure, you should be okay, as long as you stick with basic hairspray or similar for fuel. The SCH-40 is a wall thickness rating, and as far as I am aware, you are well within a reasonable safety margin if you use SCH-40. SCH-80 is NOT I repeat, NOT necessary. Just use pressure-rated parts in the future.

Bottom line: You should be okay if you don't use powerful fuels, such as propane.

jimmy101 · Thu Jul 03, 2008 2:56 pm

1. You need to read EVERYTHING printed on the pipe. That usually means you need 8 feet or so of pipe since there is a lot or writing and often half of the writing is illegible.

2. The presence of "DWV" means nothing, ignore it.

3. The presence of "Cell Core" (or something similar) means the pipe is not pressure rated. If it says "Not pressure rated" or "not for use with pressurized water" then it is not pressure rated (

).

4. Schedule 40 (SCH 40) means almost nothing. It only means that the pipe is compatible (will fit inside) SCH 40 fittings. The schedule really doesn't tell you anything else than that.

5. Pressure rated pipe will say NSF-PW (National Sanitation Foundation - Potable Water, IIRC) on it and will have a pressure rating, something like "220 PSI at 73F". If it says something like that you are good to go.

6. For a combustion gun using normal fuels (aerosols, propane, butane) in air, with perfect fueling, multiple gaps and a chamber fan, non-pressure rated SCH 40 PVC is marginal. Chances are that it'll never fail. However, most people feel a lot safer with pressure rated pipe.

DYI · Thu Jul 03, 2008 3:47 pm

Schedule 40 (SCH 40) means almost nothing. It only means that the pipe is compatible (will fit inside) SCH 40 fittings. The schedule really doesn't tell you anything else than that

The Schedule of a pipe or fitting has nothing to do with what fittings you can use with it. A SCH 80 fitting will just be larger outer diameter, and a SCH 80 pipe will be smaller inner diameter. All fittings of a certain nominal diameter will have the same ID, and all pipes of the same nominal diameter will have the same OD as the ID of the fitting (well, slightly less of course).

Schedule is nothing but a (rather idiosyncratic) measure of wall thickness in comparison to the diameter of the pipe.

nivekatoz · Thu Jul 03, 2008 4:00 pm

You can buy sch 80 pvc online ,I'll give you the web site.(well only part of the web site. because I was yelled at for advertizing other web sites,so here it is if you can figure it out. :scratch: Plumbingsupply.co???????????

jimmy101 · Thu Jul 03, 2008 4:25 pm

DYI wrote:
Schedule 40 (SCH 40) means almost nothing. It only means that the pipe is compatible (will fit inside) SCH 40 fittings. The schedule really doesn't tell you anything else than that
The Schedule of a pipe or fitting has nothing to do with what fittings you can use with it. A SCH 80 fitting will just be larger outer diameter, and a SCH 80 pipe will be smaller inner diameter. All fittings of a certain nominal diameter will have the same ID, and all pipes of the same nominal diameter will have the same OD as the ID of the fitting (well, slightly less of course).

Schedule is nothing but a (rather idiosyncratic) measure of wall thickness in comparison to the diameter of the pipe.

The derivation of the schedule is even more complex than that but for all practical spud gunning puposes that definition is correct.

And, DYI is correct, all SCH PVC pipe with the same nominal diameter will fit together, 2" SCH 40 pipe fits into a 2" SCH 80 fitting.

territorialpissings · Thu Jul 03, 2008 6:25 pm

thanks a bundle for the help guys. Ill probably just go and buy new pipe simply because i want to rest assured.

rp181 · Thu Jul 03, 2008 8:45 pm

dont bother, if it bothers you, do the bunker thing.

pat123 · Thu Jul 03, 2008 9:36 pm

can you post a picture of your gun? just so we can check for non pressure rated reducers and such. it should be fine for a spray and pray even if it is cell core but don't I don't reccommend it.
yeah DYI is right even 2" sch 40 steel fittings will fit in 2" sch 80 pvc fittings and vice versa.