SpudFiles

I made this earlier today. It is made of black iron pipe. I believe the pipe is rated to 1000psi (correct me if i'm mistaken). I'm wondering if you guys thing it will work and hold up to the pressure. In the image i attached the piston is in the top-left hand corner. It is made of hot glue and some sheet rubber. Do you think the piston will handle the pressure well? I plan on running this at 600-800psi. It will have a 2"x12" chamber and a .5" barrel for marbles or darts. I've been looking around at the pressure its rated to and in dissapointment i'm finding that my pipe is only rated to 150psi...

i really need some input on the pressure this thing can hold. i don't want it blowing up in my face. that just might hurt...

did you buy thpse fittings at a local hardware store? if so then they are rated to 150. would i take it to 600, yes

I've seen guns with black iron fittings go up to those pressures, but I'm not 100% certain. Wait until a person with experience with that material to reply.

~GF~

I think it'll be fine but I don't use iron that much... If you search on teh intrawebz there are some charts of pressure ratings for different pipes...

That piston appears to be hot glue. I would not trust a hot glue piston at 800 PSI.

i used hot glue piston for my 3/8 inch piston valve never took it above 120 well around that even with a good back stop the piston started to deform so i dont trust hot glue at 800 at all

They take 1000PSI spike from a 10x hybrid (mine included). Would I use it at 800PSI? Probably. Piston wont stand it though. Probably need to make it from some machined metal with a helluva bumper.

c11man wrote:did you buy thpse fittings at a local hardware store? if so then they are rated to 150. would i take it to 600, yes

I bought it at lowes and i sure as hell hope its rated past 150 psi. thats nothing!

EDIT BY MRCROWLEY: DON'T DOUBLE POST

Thanks for the input. Would you guys think a piston made out of sch40 pvc would work? (damn that was fast, sorry for double post) i cant machine anything, but i can buy a rod the right diameter and tap a hole in it for a sealing face.

well I suppose sch40 could, but when you are talking about pressures that high, you will probably feel safer with

a) a solid piston (not hollow through the middle) UHMWP rod would work. this is the stuff that the special large bore rounds from ultimate spudguns is made of. Super strong stuff.

b) something metal. You could try a washer and bolt piston, or metal pipe/tubing and epoxy i suppose.

Hi I had the same problem on my piston gun.
I finally found out a way to make a piston that works really well.
I took a threaded rod the leght of the piston, 3 washers , some bolts, super glue and two rubber disks a bit bigger than the fitting the piston is in.
2 washers must be the size of the fitting(I took them a bit bigger and sanded them with the dremel) and one must be bigger.
Place them like that
I---I-I
You must then glue a rubber disk in the front(sealing face) make a hole in the second and place as you can see in the diagram
II---I-II
Being the second rubber disk bigger than the fitting, it will place itself like that
II---I-)I
acting like a check valve (seals perfecly only in one way)
Depending on the thikness of the disk you vill need a spring to close the piston or a lot of air to dump. (I will post my gun soon using this sistem and will explain better.
You will need a big bumper at those pressures
Hope it helps, Daniele

cannon monkey wrote:i used hot glue piston for my 3/8 inch piston valve never took it above 120 well around that even with a good back stop the piston started to deform so i dont trust hot glue at 800 at all

this is fact. mine deforms at only 110 psi (ends up sideways in the chamber) i think maybe different types of hot glue have very different properties

well I suppose sch40 could, but when you are talking about pressures that high, you will probably feel safer with

how will you make a piston out of that? i rly want to know because i need a new piston for my rifle.

they are RATED at 150psi. what they can handle is a hole different story. infact my uncle is currently using some in a hydrolic system

c11man wrote:they are RATED at 150psi. what they can handle is a hole different story. infact my uncle is currently using some in a hydrolic system

so this means the pipe will be safe at 600psi? just gotta make sure...

Marffy wrote:

c11man wrote:they are RATED at 150psi. what they can handle is a hole different story. infact my uncle is currently using some in a hydrolic system

so this means the pipe will be safe at 600psi? just gotta make sure...

Yup.

MrCrowley wrote:

Marffy wrote:

c11man wrote:they are RATED at 150psi. what they can handle is a hole different story. infact my uncle is currently using some in a hydrolic system

so this means the pipe will be safe at 600psi? just gotta make sure...

Yup.

Thanks, now i know i didn't waste my money on pipe that cant even hold up to the pressure i want and it wont blow up in my face.