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The start to the new GB cannon

Posted: Fri Aug 17, 2007 10:06 pm
by unisonmind
so this is the start to my new GB cannon. i cant wait to finish it but i have to go out of town tomm. so i decided to post what i have done so far.

Valve specs:
Porting - 1.5"
Tee - 2"
piston-1 1/4'' coupling
chamber-3''x3' sch40
barrel-4' GB barrel sch 80 &sdr21

when putting this valve together i took a lot of pics to post for everyone to see the workings. tell me what you think

the back plug is a 2''x1'' bushing that i hit with the dremel
<a href="http://photobucket.com" target="_blank"><img src="http://i87.photobucket.com/albums/k154/ ... ure066.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>

the sealing face 1 1/2'' reducer with a piece 1 1/4'' coupling in it
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in side if the tee is a piece of 2'' sch40
<a href="http://photobucket.com" target="_blank"><img src="http://i87.photobucket.com/albums/k154/ ... ure070.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>

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<a href="http://photobucket.com" target="_blank"><img src="http://i87.photobucket.com/albums/k154/ ... ure074.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>

<a href="http://photobucket.com" target="_blank"><img src="http://i87.photobucket.com/albums/k154/ ... ure075.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>

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Posted: Fri Aug 17, 2007 10:43 pm
by PVC Arsenal 17
Looks great. Answered a few of my questions about tee valves also!

How come you kept some threading on that bushing?

Posted: Fri Aug 17, 2007 11:11 pm
by rna_duelers
Could you throw in a picture of the Piston and the sealing face?Nice and neat looking,but why is there primer stains on in the Tee?Is that a pre loved/used Tee?

Posted: Fri Aug 17, 2007 11:28 pm
by unisonmind
pvc- i wanted a close fit so the bolts could catch real good

rna-i put a pic of the piston in and the sealing face was in there 2nd from the top, and no the tee is new the primer is from when i put in the piece of 2'' pipe

Posted: Sat Aug 18, 2007 2:48 am
by spud yeti
Looks like a great valve and Im looking foward to the rest of the cannon. How much travel does the piston have?

Posted: Sat Aug 18, 2007 8:20 am
by mark.f
Neato! Good idea with using some completed threads as an "O-ring groove". Looks like it turned out real good, (although the seal will reveal it's integrity when you finally pressurize it).

Posted: Sat Aug 18, 2007 9:54 am
by unisonmind
the piston moves back from the sealing face about 3/4in

i did grind down a groove for o-ring and the small part slides into the 2''pipe inside the tee and sandwiches the o-ring in place

<a href="http://photobucket.com" target="_blank"><img src="http://i87.photobucket.com/albums/k154/ ... ure080.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>


and it does seal i tested it by putting a 2'' rubber repair cap on the end of the 90 and dry fired it at 20 and 35 psi. seals fine so far

Posted: Wed Sep 26, 2007 11:00 pm
by frankrede
Awesome!
I really like it!
Did you bore out the T so it will accept the 2" pipe all the way through?

Posted: Sat Sep 29, 2007 8:25 pm
by unisonmind
ya i dremeled it out to fit the 2'' pipe

Posted: Sat Sep 29, 2007 8:53 pm
by SpudUke5
What is the sealant on your piston? It looks familiar but i cant put my finger on what material that is.

Posted: Sat Sep 29, 2007 11:13 pm
by unisonmind
its a mouse pad it worked nice up to about 80psi then it would leaks i made a new piston this one was just a little to heavy the new one is a pill bottle filled with foam and a rubber washer for the sealing face

<a href="http://photobucket.com" target="_blank"><img src="http://i87.photobucket.com/albums/k154/ ... ure096.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>

Posted: Sun Sep 30, 2007 1:46 pm
by battlemonkey
Foam? :?:
I thought it would leak throught the gaps and holes.
nice looking gun so far though

Posted: Sun Sep 30, 2007 2:08 pm
by noname
The piston is filled with foam to eliminate pilot volume and to make the piston lighter. If it was solid PVC or something, it would be much heavier and would actuate slower. The sealing face is rubber, which won't leak (hopefully).

Looks like a great valve so far, the cannon should be pretty strong.

Posted: Sun Sep 30, 2007 4:47 pm
by SpudUke5
Thats good, well i look forward to seeing the whole thing and some damage pics. Good luck! 8)

Posted: Mon Oct 01, 2007 4:01 pm
by unisonmind