Originaly posted by ThunderousPotato,
I made a 4" combustion cannon w/ a 2" barrel for my friend jeff last summer. This thing has been fired literally hundreds of times since then...well, a couple of days ago, jeff took it out and began firing some potatoes, after one shot that landed a potato a mere 15 feet, the barrel of the gun just fell off!!!! We've concluded that the vibrations from the large combustion chamber shook the glue loose causing the barrel to come off. Possibly due to the fact that i may not have put enough glue on the barrel when i attached it to the chamber. So for all of you making a simple combustion cannon...don't use the glue sparingly, slap that stuff on there like ya have a dump truck full of it!!!
Jordan

Originaly posted by vegemite,
the substance with which you loosely call glue,is in actual fact a solvent,it destroys pvc.

think about it!

Originaly posted by spudmasterofMtWashington,
doesnt it also resalidify after the "glue/solvent" dries? then it should in theory restrengthen the joint.

Originaly posted by vegemite,
theres only so much solvent req for each joint(between the surfaces)any excess should be wiped off or it will eat into the pvc until it cures.

Originaly posted by SpudEngineerscomp,
The primer u put on first makes the
pvc on both sides soften, this makes
the solvent "glue" penetrate into the
pvc and then it "welds" the two pieces
of pvc together into one seamless mass
of plactic. This is why it is so superiorly
strong. Hope it helps.

SpudEngineer1

Originaly posted by Orangekid13,
the pvc comes loose from the gun.

or something like that

MAKE SURE TO TWIST WHEN YOU GLUE, AND HOLD FOR 5 SECONDS AT LEAST!!!

Originaly posted by Nate06,
one of our pressure tubes shot off an put a dent in alumumin siding. so if some one could give use some addvice about gluing i have done it tons of times and never had this happen do you think it could have been faulty glue

Originaly posted by Cpace,
how can you say that? ask first if he uses pvc or abs man! we usually use bas, and we put friggin lots on there, it usually comes out the joint. ph and what big of a chmaber do u use? how long is it/ ours is 3 feet long and it never fell of eh?

=cpace=

Originaly posted by Rocketbiker,
...on the back of the can. I agree the assembly process, if done timely will remove most of unwanted solvent, but care should also be taken then to remove this excess immediately. Inside and out. Any solvent on a single layer of pvc will decrease that pipes pressure level. Think about it. Solvent between two layers of pvc would be fine because theoretically the strength is nearly doubled there, but if you get excess solvent inside the pipe, there is no extra layer to help strengthen what the solvent weakened.