Nerf Quick Exhaust Valve Core

thingiverse

This is a quick exhaust valve with an internal storage buffer - essentially a 3D-printable, low-pressure clone of Spectre Nerf's SUPERcore. It has roughly 5 cubic inches (7400 cmm) of internal capacity and I've tested it at 40 psi (2.75 bar). The flow rate is so high that it bursts more than half the Mega darts I attempt to fire from it, which happen to fit directly into the orifice. The inlet (P) port is an untapped hole for a 1/4" NPT fitting (as is common in HPA rigs). The flange requires 12 M4 screws and 12 class 8 M4 nut. Print the shells (Pside and REside) in tough PLA+ or better. I'm sure ABS works. REside can be printed in either flat orientation, but I'd recommend printing flange-side-down with supports for the inner seat, rather than supportless on the business end. Quality doesn't matter. Airtightness obviously does. Use strong overlaps and many walls. Print the membrane in the toughest flexible you can get, at the smallest layer height you can manage. I used Cheetah 95a TPU at 0.1mm with a bunch of extra brim to act as a gasket. Assembly is pretty poke-yoke. Put the stuff where it fits. Grease the membrane before install if you want. If you've got it set where you want, superglue or silicone it together for a longer, leak-free life.