SpudFiles

the Grafiti Rat is a burst disk style paintball gun.

this gun was an interesting project. i thought out the designs while walking around the plumbing section of a home improvement store, so i really didn't know how it would turn out. this gun was also a cheap build (under $20, i think).

it shoots fairly well, makes good-sized dents in stuff and put a quarter-inch deep gash into a tree. And because its a burst disk, it makes a cool crack when it fires. I had to do a little troubleshooting to get the gun to work though.
overall, i am impressed with this gun's performance. The downside is that you have to keep replacing the disks after you fire and its limited by a 25 foot extension hose, but that's what i had to compromise to have more power so its all good.

sorry about the pics, i used my webcam

Looks cool but I have 2 questions,
wouldnt the shrapelnel from the burst disk bust the paintball?
and
where did you get the cpvc and how good does a paintball fit in it?

Nice cannon again

thats nicewhat do you use for your burst disk material aluminum milk jug or 2 liter plastic

i havent used the gun yet but im gonna see what materials wont damage the paintball (maybe a more flexible plastic that won't shatter so much, if that doesn't work i could try freezing the pb's).

i got the cpvc at theisen's (small midwestern chain) and its a nearly perfect fit, i got the cpvc repair coupling at menards though (another midwestern chain, i think)

i wonder if those slingshot balls would work as ammo?

.75" CPVC is like only .01" off of the size of a PB, so its almost a perfect fit. Although CPVC is different sizes then regular PVC. I ended up sanding down a coupling so that it could fit inside of a 1" socket for PVC. Although they should have some transition peices.

Nice gun,What your estimate on distance?And when do you get to fire the mean thing?Cuz i wunna see some damage pics....Always with the damage...

what did gas gun design tool say?

i'll bring damage pics for this gun as soon as i get my hands on a digital camera. I'm planning to fire it tonite

i didn't use the GGDT because i don't have one. i'd like to use that.
don't you have to pay to get one? or use paypal or something?

LATER THAT NIGHT: I finally fired the gun after waiting 24 hours. the results are posted at the top.