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1/2'' piston valve

Posted: Sat Sep 15, 2007 11:02 pm
by hi
My next project/ "cannon" is to make a little pellet pistol.

i wanted to make it out of copper and brass. I want to make the main valve a piston valve fitted into a 1/2'' tee and have it port directly into the barrel, which will be 1/4'' brass tubing.

my question is how do i fit the barrel ito the tee? the two solutions i can think of is to

(A) drill a hole into an end cap and put the barrel trough there and seal it with epoxy or

(B) make the reducer totally out of epoxy.

which will wok best? any thoughts or comments?

this is the basic design at the moment...

Image

keep in mind that this is a VERY rough drawing of what it will look like. it will be made of copper, not pvc and everything will be tighter together.

edit: i forgot to add that i will use this at about 150 psi.

Posted: Sat Sep 15, 2007 11:11 pm
by jackssmirkingrevenge
http://www.spudfiles.com/forums/bb-gun- ... rt,15.html

what sort of epoxy do you have available?

Posted: Sat Sep 15, 2007 11:19 pm
by hi
I guess i missed that thread.

thats a good idea using a dowl.

i have epoxys such as JB weld, 5 minutes epoxy, 10 minute epoxy, 1 hour epoxy, 24 hour epoxy, elmers epoxy... so on and so forth.

if i use the marine epoxy you do Jack then i'd have to order it online.

pretty much anything at the "Do it Center", Home Depot or Lowes.[/quote]

Posted: Sat Sep 15, 2007 11:41 pm
by trae08
umm they make copper 1/4"x1/2" reducers

Posted: Sat Sep 15, 2007 11:42 pm
by jackssmirkingrevenge
Marine epoxy or equivalent is the only one I've found to be good for actually casting reducers etc. If you're using anything else (usually the longer it takes to cure, the stronger the result) I suggest a tight fitting wooden endcap as suggested in the above thread then securing it with epoxy.

Posted: Sun Sep 16, 2007 9:23 am
by noname
Use a compression fitting; it's the simplest, best looking way.

Posted: Sun Sep 16, 2007 10:06 am
by VH_man
that looks like it will be fun. dont forget to make it able to take insane pressures for just THAT MUCH MORE FUN!!! lol.

i am currently working on a small marble handgun, wich when pressurized at 100 PSI gives a modest FPS of about 350. not too bad for a150 PSI and a 5 inch barrel!!!!

should give some kick though, wich is what im looking for. something that when i pull the trigger, the pistol snaps back in my hand and i see my target blow up into shards............

anyway, i like that, be sure to post it when its done, theres something alluring aobut the pistol.....

Posted: Sun Sep 16, 2007 1:57 pm
by hi
noname wrote:Use a compression fitting; it's the simplest, best looking way.
what exacly for?

Posted: Sun Sep 16, 2007 3:40 pm
by noname
hi wrote:my question is how do i fit the barrel ito the tee?