Airtight?

[JJ pyro]

Hi

I have been building a pneumatic cannon, only i have been having a hard time on having to try to get it airtight. Does anyone have any suggestions or tips on how to get my gun fully airtight??[/color

[pvcmaster]

Is this a threaded cannon, because you shouldnt be having problems with solvent welds (primer, cement).

[paaiyan]

Did you use PVC primer and cement on every joint? And teflon tape on every threaded joint?

[meatballs]

can you please give more info as to type of cannon, what type of leak, where, and all that stuff? that would help us give better suggestions.

put the cannon in water, and look for where bubbles come out.
if you're having trouble with solvent welds sealing it probably means that you didn't make a good joint, or you did something really wrong during construction. if this is the case then you should probably not use the leaking solvent weld, it may not be strong enough to be safe even if the leak is fixed.
if its a problem with a threaded joint then use more teflon tape. use lots of teflon tape. if you're using pipe joint sealing compound switch to teflon tape. remember, teflon tape is your friend.