Takes the fun out of making it yourself, but these are available on Ebay for just a few pounds – recently bought one for testing a friend’s steam engine and it worked fine.
Dougie are you after a demand regulator which is what Michael’s is or simply a flow regulator and also what type of “can” Sounds more like a propane/butane mix camping gas type cylinder in which case I’m with The Cowboy and use the ones from ebay, the small stove burners they often can be bought with are good for heating hot air engines.
Jason got there first ! PROPANE ? Or a low pressure gas mix ? Propane, you are looking at a bottle pressure of 150psi, not to be treated lightly ! Noel.