Simple Boiler

Tony Bird · Nov 25, 2014

Hi,

Recently I have made a replacement hard soldered copper boiler for a model Mamod locomotive. The original Mamod boiler is brass with a Plexiglas viewing window for the water level. If the boiler is allowed to run dry the Plexiglas melts and sometimes the soft solder that holds the boiler's end cap also melts. The new boiler is a simple pot boiler with two take off's one for a filler valve the other an attachment for a safety valve and regulator. The coper tube used at 1.7 mm thick is about twice as thick as necessary for a boiler operating at 25 psi but the tube was available and cheap. The boiler was tested to 100 psi for another possible application for a higher working pressure without having to fit a longitudinal stay. There was no significant defection of the end covers so the boiler should be OK for up to a 50 psi working pressure. A 22 mm stop end has been used as a steam dome/filler valve cover. I hope the photographs explain the construction techniques used, if not please ask.

Regards Tony.

TorontoBuilder · Nov 25, 2014

Thanks Tony!

That's a very clear photo essay, I particularly like how you used turned parts as swages and forms to shape the boiler parts. I didnt know how easy it is to fix old mammod toys by replacing the boiler

Jyman · Nov 25, 2014

Very nice work, I love the mamod live steam trains. Just wish I could find them second hand out my way.

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gus · Nov 27, 2014

Congrats.
The end caps were very well done and finished and so was the solder. Was it soft solder or Silver Solder.

Tony Bird · Nov 28, 2014

Hi Gus,

The boiler and its fittings are hard soldered (silver soldered) together.

Regards Tony.

gus · Nov 29, 2014

Hi Tony,

The Silver Brazing was very well done and cleaning up very good.
Silver brazing is a skilled not easily picked up. Constant practice required to pick up the skill.The air conditioning guys made it look so easy with the silver solder spreading 360 degrees into the joint. So did my Trade School Instructor in 1961. A good friend in this trade taught me to braze. Until then it was nothing but globs that went no where. Eventually I did brazed 6 mini boilers. A simple brazing hearth does miracles.