blow down.

[London_lighterman]

A very good evening from London Uk.
I wonder could the panel give some advice on loco boiler blowdown valves.

I know there is much written and murmured about the use of brass in boiler fittings, and case in point the ones I have just extracted from a loco were close to dust, strangely not much at the wet end in the bushing but the body of the valve.

I see that a lot of the commercial fittings are brass and while its a much nicer material to work with I would like some thoughts on a combination of materials IE  gunmetal shank go into the bushing in the outer wrapper and seat for the ball and brass body. stainless valve spindle...

Am I building a Frankenstein with possible galvanic tendencies?
Thanks in advance.

[Jasonb]

For the small amount of material involved I would just use bronze or GM for the whole body.

Stainless is OK for the spindle and you can just have a chamfer on that directly onto the seat so no need for a stainless ball.

There are grades of brass that are classed as DZP Dezincification Proof but harder to come by in our small quantities.

[steamer]

Getting the proper bronze would be the way to go.   I mean think of the time you spend on making it.     The material is the cheap part, and the right material .   (Tobin Bronze?  Gun metal?   What ever your local model boiler code says)   makes the job a lot safer...

Dave

[London_lighterman]

Thank you.
I will re think the idea.
always a pleasure bringing my questions to a knowledgable mess room.