SpudFiles

ok well i went to the hardware store today looking for some cheap parts because usually they are the best priced.. i asked if he had 4 inch pressure rated fittings. he said yes. he took me to a room and asked what they were for and my dad jsut blurted out "a potato cannon" like usual...i keep telling him not to... and the guy said oh and showed me the parts.. (gladly he gets alot of people who build potato guns i guess) he asked me if they were the right ones so i picked one up and it said nsf-dwv. i said no these arent pressure rated. then he said "sure they are, these can take atleast 300-400 psi, they are sch 40". i kindly told him that sch 40 wasnt a pressure rating jsut a thickness rating. He said he knew that but pressure ratings depend on temps. and what not said that there are two kinds of dwv, cell core, and regular. he said the regular dwv was fine for pressure and could take what he said earlier...

now before i buy these (damn 4" parts are expensive) i want to know if they are safe or not because i am a little sketchy about them...

Thats really suprising. DWV is usually meant for underground or low pressure so I dont know.
My only suggestion is get a piece, make a chamber out of it, put it in a thick bag, and test it to like 400psi...
Anyways, if it does blow up on you, just blame him!

Nah im not going to buy it until i am sure that it is pressure rated..the effing caps are 7 USD apeice! thats efifng outragous!!

oh and is NFS-61 pressure rated? (fittings from mcmaster)

Holy crap thats expensive! Why dont you just use PVC then?
I dont know about the NFS-61, sorry.
Oh ja, I'll post my gun onto your site when its completed. Nice site, almost as cool as mine...Kidding! Post some of yours on my site too if you want to. (the more complex ones please, as this is the focus of my website)

Why dont you just use PVC then?

thats the problem!!! it is pvc!!! thats how much pvc is!! the metal 4 inch threaded caps are actually less than that!!

oh and what do you guys use for your huge guns...i cant find anything that is pressure rated for 4" pipe..do you guys jsut use unrated stuff?? argh schmanman what did u do!! help me! ahrgakasdg;asdfklj!

Ja, of course, stupid moment there. Imeant to say pressure rated nfs or whatever it is pvc!
It is insane how much pvc costs..... Where I live there are so many building sites with it that I never need to buy any, and I generally build in metal.

i build all of my guns out of metal..this is like the second gun out of pvc.. theres no way i would build a 4inch gun out of metal...

look at my edit up there guys...where is schmanman where u need him.. (spudshot maybe?)

Ok, this is what I know of US pipe:

DWV can be pressure rated - Or rather, pressure rated pipe is occassionally marked with DWV, indicating it can be used for that purpose.

But if it's not marked with a rating, it's not rated. As you said, SCH 40 is not a rating.
DWV can be solid wall, and still not be suitable for pressure.

Check for a rating printed on the pipe. If it doesn't have that, steer clear.

its not a pipe though..its a fitting..or fittings should i say. and all it says on it is nsf dwv. but the guy said it was for pressure applications..and can take 300-400 psi..but im still not sure and want alot of opinions/ facts before i buy it

FFS guys - pretend you got a pair and stop moaning! 7 bucks is nothing! Over here a 4" endcap is 7 quid that's 14 bucks! Plus VAT at 17%, your getting on for $16!

If you build big expect to pay $$$$

Michael

NSF-PW and NSF-DWV just refer to socket depth not pressure rating,
joaanaardway is right pressure pipe is usually marked as DWV as well. i have used DWV fittings before up to 90 PSI with no problem. this doesnt mean its safe it just means that i havent had a failiure yet, try and steer clear of DWV. try looking at a local plumbing suppy store, things are usually cheaper there,

If you do use DWV make absolutely sure that your solvent welds are correct. Clean pipe then primer than glue.

Michael is right big cannon= big$$

NSF-61 and NSF-PW both are pressure rated.


Just don't get them from your local hardware store, and use mcmaster. It might be a little more expensive, but it's alot cheaper than the hospital bills to get your arm sewed back on..

rednecktatertosser wrote:NSF-PW and NSF-DWV just refer to socket depth not pressure rating,
joaanaardway is right pressure pipe is usually marked as DWV as well. i have used DWV fittings before up to 90 PSI with no problem. this doesnt mean its safe it just means that i havent had a failiure yet, try and steer clear of DWV. try looking at a local plumbing suppy store, things are usually cheaper there,

If you do use DWV make absolutely sure that your solvent welds are correct. Clean pipe then primer than glue.

Michael is right big cannon= big$$

NSF-PW stands for Potable Water and doesn't have anything to do with socket depth. It is for pressurized water and the like. None of the pvc pipe we use is meant for air pressure, but we do anyways.

Never use DWV on a pneumatic, even if "your solvent welds are correct."

NSF-61 is a rating for drinking water components, it would also be better to use than DWV.

(again) Edit: I meant to say try sites that are online, not just McMaster. 4" fittings can be somewhat expensive even online. But it's worth it. I dont think you can actually order from harvell, so look around.

im pretty sure nsf-dwv and nsf-pw arent jsut socket depths..as i have seen the same socket depth and different ratings..(nsf pw and dwv) and there is dwv pipe how is there a socket depth on pipe?

and it was a local plumbing store..the bigger stores are even more expensive.

and ur supposed to sand the pipe, clean it, prime it, then glue it

@modder- a little more?!?! i jsut checked mcmaster and its costing me 50 dollars for 5 parts and they dont even have everything i need!! i am definately not ordering from mcmaster..

@spudthug-
oh i thought DWV and PW refered to socket depth, go look at a PW coupler then a DWV coupler and youl see what i mean.

@modder-
potable water dosent mean its pressure rated it just means it is safe to use for pottable water systems...

@spudthug-
if the metal is cheaper just use that...

Just build a smaller cannon if the money is going to be a problem.