How to solvent weld barrel to modified reducing bush?

limbeh · Sun Feb 24, 2008 9:40 am

Hi,

I'm now in the process of putting the parts together for my first cannon. I've modified my PVC 4x3" bushing, but now I'm about to solvent weld it to my PVC 3" barrel. Yes, I know the process, but I'm not sure how to do that with a modified bush and barrel. Apparently you have to slide the barrel into the bush, but I'm not sure how to do that without making all my cement dry. I thought of cutting my bush up & solvent welding it back onto the barrel, but realised that it wouldn't fit (LOL).

Any of you guys who has built a piston cannon can care to share?

Thanks.

frocksie · Sun Feb 24, 2008 9:56 am

What I do is place a liberal amount of cement on the modified bushing, and then put primer and cement on the barrel up to the point where it will be seated.

limbeh · Mon Feb 25, 2008 8:00 am

Thanks for the advice.....but does the barrel get weakened or deformed as a result of adding the primer & cement?

Hmmmmm, I was sort of expecting some of the moderators (eg Mr Crowley, JSR etc) to either answer or scold me if the topic was a repeat.
They're pretty efficient, as lurking around for the past 3-4 months has shown.

Carlman · Mon Feb 25, 2008 8:36 am

1) slide the pipe through as a dry fit and mark where the weld will be

2) take the pipe out and apply primer to the marked area and the inside of the bushing

3) apply glue to inside of bushing and primered section of pipe (more so on pipe)

4) slide pipe into bushing so that the desired area is in the bushing.

limbeh · Wed Mar 05, 2008 6:47 am

Hi,

Ran into another problem while following your advice. That mixture of glue & primer which I used is somehow very viscous. I was unable to even slide the bushing halfway through to the designated area. This is even after getting a couple of strong people to help me push the thing in. Without glue, the pipe slides in pretty easily. Temperature is about 25C & 90-100% humidity, as is of Singapore's climate.

The PVC cement is the normal kind, some clear, but viscous stuff. The primer is IPEX purple primer. This got me thinking a bit: Should I dilute the PVC glue with water?

As for the moderators, I know that this post is bringing up a past topic, but I hope you understand what's going on.

Thanks.

Carlman · Wed Mar 05, 2008 7:17 am

limbeh wrote:This got me thinking a bit: Should I dilute the PVC glue with water?

NO!!!!

well only if you want your joint to fail miserably under pressure that is

limbeh · Wed Mar 05, 2008 9:24 am

Hmmmm...........good point.

So, anyone got other ideas on how to lubricate the glue & primer?

Carlman · Wed Mar 05, 2008 10:14 am

give the inside of the joint a light sand with a light/med grit paper just enough so you can push the pipe through

Jared Haehnel · Wed Mar 05, 2008 10:15 am

Why don't you slide the barrel in, after priming both surfaces, get it to where you want it then slide the barrel out a few inches apply a liberal amount of cement and then slide the barrel back into the bushing to where you want it and twist until it won't turn anymore...

limbeh · Wed Mar 05, 2008 10:44 am

Ok......man, I didn't think of that. Thanks.

Anyway the gun that I was building was a dummy cannon, it either doesn't work (with no piston inside) or explodes (due to improper joints), an excellent way to teach itchy handed buggers a lesson that it does not pay to fool around with my stuff (I am building & storing these spudguns in school). So, no worries on safety issues, I don't intend to fire that thing myself.

Thanks for the help so far, guys!

From Singapore