SpudFiles

Quick question : would adding thread coupler to the chamber ( to make it removable) would weaken the chamber to the point of making it explode at the point of the threads?

Depends on what size/type of gun.

If its a 6" SCH 40 hybrid with sch. 40 fittings... then possibly

If its a 2" combustion, then probably not

I use 4" fittings on my pneumatic (which has a 6" chamber), and then have been no problems. Keep in mind, PVC has a huge safety factor (I think i said this yesterday in another thread....). Some PVC pipe manufacturors (sp?) recommend derating the pressure rating of the pipe 50% if you use threaded fittings.

As long as you solvent weld the threaded fittings in properly, use a quality sealing material to seal the threads, and tighten them enough, you should be fine.

First of all if you are using pressure rated pvc in a propane combustion cannon, there is no way in hell it will ever explode!
Just remember to solvent cement correctly and practice safety when using spudguns and you should be fine.

I am using ABS Pipes (SCH40). The chamber is 4", the barrel 2" and I would add Thread couplers on the chamber.. Just before the bell reducer.