SpudFiles

I finished my first pneumatic cannon and it is interesting. I know how everything works and whats leaking but everytime I seal the leak and then re-pump it leaks. Is there a specialy glue besides pvc glue that you guys use?

Epoxy works, so does thin super glue because it spreads around the joint quickly and seals evry little hole.

im not the brightest crayon in the box when it comes to pneumatics but im pretty sure that you just use regular pvc glue for pneumatics. i wouldnt really know though im a combustion guy.

I only have one brass part on this cannon, used for a connection from the airtank to the pvc that connects to the solinoid, would the epoxy work on the brass also?

You're totally sure it's leaking from the pipe joints? There is the posibility it is leaking from the fill valve or other misceolanneous fittings attatched to the cannon. Also, you're using primer right? That might have something to do with it...

put soapy water in a spray bottle and preaseurize your chamber. when you find a leek, mark it with a sharpie. then seal them all with 30 min epoxie. i love that stuff

Did you use Teflon tape? Rule of thumb: if it leaks and is threaded, tape it; If it’s not threaded, and doesn’t need to be removed, Goop it. Otherwise, consider O-rings.

Im sure the pipe joint is leaking. I used pvc glue many times and it still leaks. Right now I can only reach 45psi because of the leak. Im about to rip it apart and make a whole new gun. For the people who want to know, the leak is were the threaded brass (male) and the threaded pvc (female) parts meet. Yes I used teflon.

Could that be why the? PVC joining to brass. I know its okay with fittings like QD's and gauges etc but has anyone ever done that before?

can we have pics of the area of concern? i wouldnt want a good gun to dies so young

why dont you scrap that gun and make a combustion its easier!

If thats the problem then I can get a 1 1/2in to 1/2in fitting for pvc. Would that work better? Pictures will be up by tommorow because of it being late night. And I cant make a combustion cause my parents wont let me buy anything that has to do with sparks and a flamable gas. I wouldn't trust myself with it anyways.

same story with my parents. even though they witnessed my put a hole in a peice of ply with my pneu.

use good pvc glue and make sure all your joints are clean use pvc primer or sand paper on all the joints

Honestly, if the joints are leaking, and this is supposed to be a pneumatic, chop off the leaking fittings and start over. Some members may tell you to use epoxy, and this may temporarily work. However, you will never have the piece of mind that your gun is completely safe and will not break. Even if the epoxy seals the leaks in the joints, these joints still do not have integrity. There is a chance they will shoot off, possibly taking chunks of the PVC pipe which they are solvent welded to with them. And you DO NOT want to be near your pneumatic if that happens.

In short, I'd restart. You will be glad that you did in the long run. Unlike combustions, pneumatics require proper pressure rated materials and quality construction techniques.