SpudFiles

it seems that most guys use HDPE for burst disks, what pressure do these burst at? i have been using metal tape on my gun(havn't had a sucessful hybrid shot yet, only pnumatic testing) it is a thin plastic like tape and bursts around 100psi in a 3/4" black iron union with the tapered part facing the barrel. what other materials work well for holding high pressures.

I don't have a hybrid, but have studied them quite a bit (I hope to build one next year, funding dependant). Most people use several layers of aluminum foil, or discs cut out of a milkjug or soda bottle. Any hard, thin plastic should work. Hope that was kind of helpful.

Peace,
Pete Zaria.

No numbers regarding steel unions, but PET (2 Liter bottle thickness) typicaly slips out of plastic unions at around 100 PSI.

Thanks, all i have to do now is wait for the epoxy to dry around my ignition wires then I can do a real hybrid shot.

I'll try both materials and post the results.

I use parchment paper and it bursts @ 45 psi with my 1" union

In my 3/4" PVC union, I use scotch white duct tape. It goes at around 100 psi.

I use two layers of aluminum foil, and that bursts at around 60 PSI.

BTW, what's your hybrid like? Is it all steel, or is that just the union?

Sheet Aluminum, Very thin.
Would it work?

it was all 3/4"black iron but i could never get it to fire. i now know why, i would have had to use 3psi in my meter pipe, i was using 10. i also had a terrible spark setup. i may revisit it but not right now. it actually didn't cost me anything, i used various stuff laying around my garage. in my pneumatic testing i managed to shoot a sharpie marker about 80yds by accident. the silver metal tape worked the best for me pneumatic.

I am gonna use soup can lids for my 20x hybrid.
No idea at what pressures they would burst at....

lol...a lot.

you better be a long way away from that when it goes off. thats about 300psi before ignition.