SpudFiles

is there a way to glue copper to PVC so that makeing a coaxial cannon i could have the chamber PVC and the barrel Copper? (meaning i dont want to screw the copper into the PVC reducer, it has to go through the reducer).

It is impossible (or at least very unsafe and impractical) to connect copper directly to PVC in a pneumatic unless it is using threaded fittings, cam-locks, etc.

So you want a copper barrel for your PVC cannon? There are a few options

First of all, you can get a copper male adapter (which is the same size as your chamber) and a bushing that reduces the chamber size to your wanted barrel size. Solder the bushing into the male adapter, and then solder the barrel onto the male adapter. Just connect it to the PVC by a female adapter.

Another option is to sleeve the copper barrel inside of a PVC pipe, and then solvent weld the PVC pipe to the reducer.

the only reason im asking is cause im having a hard time finding 3/4" PVC pipe yet there is tones of 3/4" copper pipe.

EDIT::

How about connecting brakeline to copper... can they be soddered together?

actually it is possible to adher prv to copper . Your looking for IPS Weld On # 845.