semi-hybrid

[metallover]

What about Oxygen?

[THUNDERLORD]

oxygen is $7-8 per container and propane $2-3 (16-18oz. can)
I'd recommend, stick with starman's advice or refer back to bigbob12345's first reply. If you want something more powerful, build a metal one.

[DYI]

Oxygen isn't even a fuel...

However, if you're talking about replacing the existing 20% O₂/79%N₂ mix with 100%O₂ and then adding the correct amount of fuel, I'd say don't do it in PVC. PVC is already a very poor chamber material, and the sharp, high pressure spikes of oxygen enriched mixtures don't help existing fatiguing problems in the chamber material.

For a given oxidiser, ethyne is likely the most powerful commonly available gaseous fuel you can use, and MAPP is the most powerful you can use if you'd like the chamber to remain intact after the first shot.