burst disk material

[rocketman]

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.

[Pete Zaria]

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.

[boilingleadbath]

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

[rocketman]

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.

[pyro86]

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

[PVC Arsenal 17]

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

[mark.f]

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?

[frankrede]

Sheet Aluminum, Very thin.
Would it work?

[rocketman]

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.

[benstern]

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

[rocketman]

lol...a lot.

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