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 Post Posted: Mon Jul 07, 2003 7:00 pm 
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Originaly posted by andeh,
I cut out the metal, going to file it down... anyhow. Once I cut out the neoprene, the 1/32" goes on the back of the plug right? Can I use JB-Weld to stick it on?

Also, is there a specific reason why the diaphragm uses a bolt as opposed to JB-Weld or something like that? There may be something I'm missing here, but I think that the bolt isn't needed... thanks for ALL of your help, I really appreciate it.

by the way, I have my chamber assembled and the bushing filed down, the outer shell of my barrel should be here tomorrow. Inner sleeve... not sure yet.


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 Post subject: oh... also...
 Post Posted: Mon Jul 07, 2003 8:00 pm 
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Originaly posted by andeh,
should it be safe if I drill a 1" hole in the cleanout plug and thread my 1" brass nipple in it?


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 Post subject: Diaphragm
 Post Posted: Tue Jul 08, 2003 7:00 am 
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Originaly posted by mta,
The 1/32" neoprene is glued to the back of the cleanout plug. It may not be necessary, but I've always used it. Cleanout plugs are cheap (relatively), so you can experiment. For glue I use contact cement (DAP Weldwood "the original contact cement") with good results.

I have tried gluing the 1/8" neoprene to the metal, and have tried other diaphragms with glue, but they always come apart. It's quite violent in there. A bolt through the 1/8" neoprene and the metal works very well. I use a 1/4" bolt. Buy or make a nice big fender washer for the top of the diaphragm.. it should fit nicely inside the breech. On the underside use a small neoprene washer (make it yourself from left over 1/32", flat washer, and locking nut.

I've never used JB Weld, but it appears to be a fast setting 2 part epoxy. I'd be surprised if that would hold up. Experiment though. The worst you'll do is mess up a diaphragm.



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 Post subject: 1" seems awfull big
 Post Posted: Tue Jul 08, 2003 7:00 am 
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Originaly posted by mta,
A 1" nipple is awfully large. Will it even fit? The gun you are building doesn't need to vent as much air as most piston guns. You can get away with a smaller dump valve. I use a 1/4" quick exhaust on my 1.5" x 3" guns, and a 3/8" quick exhaust on my 2" x 4" guns. That works fine.

But the good news is, if you try a 1" nipple and it doesn't work, all you have to do is buy a new cleanout plug and try again.


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