Boiler End Plates

[Bob SillitoeParticipant @bobsillitoe83708]

I am planning to start making a simple steam engine soon, probably based on one of the designs by Tubal Cain. The turning and milling work will not be new to me but making the boiler will be a new experience.

I am just wondering about making the boiler end plates, all the designs I have seen involve forming a sheet of copper or brass to the required shape. However it would seem possible to me to make one on the lathe from a piece of brass plate. I think I would be able to get similar profile and a better fit the the barrel of the boiler. So just wondering if there are any pitfalls with this approach.

Thanks

Bob

[bernard towersParticipant @bernardtowers37738]

If you use annealed copper sheet spinning would be a good option as the engine size seems quite small. The advantage with spinning the ends is that if spun slightly oversize can then be skimmed to fit the boiler barrel

[duncan webster 1Participant @duncanwebster1]

Boiling water can eventually leach the zinc out of brass leaving you with a weak sponge like material. How long depends on water quality, after all, Mamod boilers seem to last a long time.

Forming annealed copper is quite therapeutic, just remember to re-anneal as soon as it puts up any resistance

[Thor 🇳🇴Participant @thor]

Hi Bob,

I used spinning to make the copper end plates for my simple pot boiler, see here.

Thor

[noel shelleyParticipant @noelshelley55608]

DO NOT use brass ! As above – dezincification. What sort of size ? Mamod ?Depending on the type of brass you may have trouble forming it – bent sharp unannealed  it may well crack. Anything solid even wood will do for the former and you may find a copper heating cylinder thick enough I have one that is 1.2mm. Depending on size and thickness some staying may be needed unless it is very low pressure, eg a pot boiler. There are books that will give you good guidance, eg Model boilers and boiler making. by K.N. Harris. Use rain water as feed. Good luck. Noel.

[BazyleParticipant @bazyle]

Finally copper is softer and easier to work than brass. Start with the biggest boiler even if you aren’t making it yet. Then if you mess it up you can use the plate for the next smaller etc.

[Bob SillitoeParticipant @bobsillitoe83708]

Thanks for the advice, forming or spinning the plates sounds fun and interesting and really the right way to go.

However the boiler is small about 1 3/4 in diameter and I have some brass plate about 3/4 in thick which is why I am wondering about trying to machine some end plates. With care I think that I would be able to get a profile similar to spun ones although they might have to be a bit thicker.

I am aware of dezincification but although I want the engine to run I doubt it will be used that often so hopefully not too much of an issue. My Mamod boilers from the mid 60’s show no sign of it.

Bob

[Martin Johnson 1Participant @martinjohnson1]

There are different grades of brass, taps for domestic plumbing for example, are made from a de zincification resistant grade.  Mamod might possibly have known what they were doing and chosen a suitable grade.

Use copper for your end plates.  If you don’t like spinning, you can make a pair of steel dies and press the copper at one go if you have access to a press of a few tons capacity.

Martin

[JasonBModerator @jasonb]

For such a small boiler you could probably go for flangeless and just solder discs of copper onto the ends rather than fitting into the tube.

[BazyleParticipant @bazyle]

There have got to be better uses for such a nice piece of brass – have you seen the price!

[Bob SillitoeParticipant @bobsillitoe83708]

Hopefully you have all spotted the obligatory typo, the plate I have is 1/4in thick not 3/4in

[Author]

Posts