Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Jim, there is a reason why propane cylinders have to be tested on a 10 yearly basis, due to the high pressure, a thin butane canister would never pass the test.
I would suggest that if you want to use propane then get a small propane bottle.
Butane is cheap enough from bunnings as is propane.
Please do not risk it mate.