(Just for fun, we're reprinting the original content for a project we did in our early days, late 90's and early 2k's. Enjoy)
(by Colin Moritz)
OK, what exactly was being smoked when this was built?!? PVC fumes have got to be toxic.. because that and only that can explain this contraption. This is a paintball marker, with the body made entirely of PVC. It is closed bolt, and it operates at around 60PSI! Its valve design is based on the old pressure-difference "pop" disk. While it does allow an ungodly amount of air to pass through it when opened, it is VERY in-efficient. Also because of the spring-returned single-acting home-made air-ram (any more hyphens??) controlling the sleeve bolt, its re-cycle rate is pretty far down there.. around 3 or 4 per second.
The trigger mechanism is based on that of an Automag.. It performs dual actions upon firing. As it is pulled, it first seals the air chamber off from the air supply via an "on-off" valve. Then it releases the "dump" port on the back via a ball-bearing "sear".
If you are looking for a 4 or 3-way, keep looking.. its not there. The air ram operates off the main air chamber.. as the chamber is pressurized, the air ram moves the bolt forward. After firing, and the air chamber is empty, there is no longer any air pressure on the air ram, so the spring returns it back to the open position.. as long as the trigger is held and the air is cut off from it.
This entire marker was built mostly from PVC, 1/8" think aluminum, some nuts and bolts, and some R/C car ball joints and shock cartridges (for the air ram and modified internals for the on-off valve). It takes stock Spyder barrels.. but they thread directly into the PVC... so thread life will probably be pretty short. :/
All it needs now is a nice adj. output tank (60 psi?!?) and a (pvc?!?) dropforward..