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

Putting a ball valve on the exhaust is an interesting thought...

I did find a company in UK that makes nice looking miniature ball valves...I do not know what size steam tube wilesco uses at this time but see they sell it in bulk with 3.5mm OD

Wilesco does sell a steam control valve replacement for there larger engines but the parts it comes with is a combo of parts some threaded, others not...so I am not clear if it's a solder in production or compression fittings.