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My GB cannon

Posted: Sat Sep 19, 2009 9:10 pm
by jor2daje
I got my sdr21 yesterday so today I got some 2" sch 80 and made a golfball gun. The pics are self explanatory but this is my favorite gun to date because I think I finally found my balance between chamber size (I only have a little compressor), calibre (tennis balls are too big, nails and bb are a little small), and size (it can easily fit in my car). \

UPDATE: I built my breech today, its really straight forward, a hole in the barrel the size of a golfball and a piece of sch80 that slides over it. The hole has some tape inside to act as a detent so the ball doesnt roll out of the barrel. After putting the breech on I sorta feel like adding a sch80 muzzle break to get the white and grey fittings of different sizes on the gun. Tell me what you think.

Specs:
Its a 1 1/2" porting in a 2" tee, sdr21 for the barrel, and 2" sch80 for the chamber, I used sch80 because I got a great deal buying it by the length so I have tons left over, and because its rated to 400 psi. Pilot is a 3/4" sprinkler piloted by a blow gun. After my tennis ball gun leaked a little where I attached the quick connect I decided to sacrifice some pilot volume (sorry jsr :D) and get a perfect seal using threaded joints and bushings. My piston is a 1 1/4" end cap with a round piece of rubber tile on it, I used the same shopping cart bumper as I did on my tennis ball gun.

Breech loading should come tomorrow I just have to sand down the inside of my sch80 cause the fit is slightly too tight.

Only a few damage pics for now because I only made it today so I only went to 40 psi until Im confident the cement has completely cured. I promise Ill up the pressure and the damage.

Any feedback/ recommendations welcome, the tape one the barrel and pilot supports will be replaced with hose claps hopefully tomorrow.

Posted: Sat Sep 19, 2009 9:13 pm
by JDP12
Very nice cleanly built gun!! I Love it!

Posted: Sat Sep 19, 2009 10:12 pm
by Mitchza89
Beautiful mate, it looks amazing. Job well done!

Posted: Sat Sep 19, 2009 10:19 pm
by spudtyrrant
nice job, man you should have included the feet then we might see some fireworks when jsr gets around here :D

Posted: Sat Sep 19, 2009 11:04 pm
by jor2daje
Thanks guys

haha spudtyrrant ill add some feet when I take the picture of the breech I put halfway down the barrel so I have lots of deadspace :D

Posted: Sat Sep 19, 2009 11:06 pm
by MrCrowley
Only a few damage pics for now because I only made it today so I only went to 40 psi
Can't that put air pockets in the weld and make them a lot weaker?

I heard that somewhere before, regardless I still wouldn't subject a PVC weld to pressure before the 24 hour cure time is up.

Anyway, looks nice. Glad to hear it seems to be working wonderfully.

Posted: Sun Sep 20, 2009 12:50 am
by jor2daje
Mcrowley that possible so thanks for the heads up but I did wait like 10 hours before even going to 40 and on some older guns I have pumped up before the 24 hours and never had one break. I think air bubbles could only form in the first few hours when the glue is either still liquid or a goo. Thanks

Posted: Sun Sep 20, 2009 2:22 am
by qwerty
Looks good, but what pressure WILL you be running at? cause i cant wait to see some good damage pics and maybe could you do a video? pretty please! :)

Posted: Sun Sep 20, 2009 9:49 am
by geniusbomberman
You should maybe use some of that sch 80 2" on your barrel, as thinwall sdr 21 might not be strong enough

Posted: Sun Sep 20, 2009 9:58 am
by jackssmirkingrevenge
spudtyrrant wrote:nice job, man you should have included the feet then we might see some fireworks when jsr gets around here :D
Why do you torture me so :roll: :D

Nice job, simple, neat, looks good and works well :)

Posted: Sun Sep 20, 2009 10:09 am
by jor2daje
Geniusbomberman I dont think I need to sleeve my barrel, for one thing it makes breech loading more difficult and my sdr21 is rated to 210 psi so i think its only necessary to sleeve my barrel if its so long it starts drooping.

Posted: Sun Sep 20, 2009 12:47 pm
by jor2daje
Sorry for double post but UPDATE, I made the breech and added a damage pic, more to come.

Posted: Sun Sep 20, 2009 1:02 pm
by spudtyrrant
jackssmirkingrevenge wrote: Why do you torture me so :roll: :D
jack..jack..jack....you only torture yourself to make me look bad :D

Posted: Sun Sep 20, 2009 1:59 pm
by mark.f
Looks great! Nice, solid, reliable design.

Posted: Sun Sep 20, 2009 10:30 pm
by geardog32
that is the most appealing way of using a sprinkler valve for porting i have ever seen. it may inspire me to use a sprinkler on my piston valve. very good job.