Traction Engine Boiler

[norman valentineParticipant @normanvalentine78682]

I went to the Newark Autojumble yesterday and found this nicely built boiler that was in filthy condition. I had concerns about the material it was made from but bought it anyway. On cleaning it up I found that, as suspected, it was made of steel. My question is why would anyone invest so much time an energy in making a boiler from a totally inappropriate material? It had occurred to me that it could be the basis of a static model. Can anyone identify if this is made to a published design?

There are a two more pictures in my album entitled "boiler"

By the way it only cost me a fiver.

[norman valentineParticipant @normanvalentine78682]

[Alan Waddington 2Participant @alanwaddington2]

I'm not a model engineer, but was a boiler maker in years gone by, so please bear with me here……..I'm curious as to why steel would be classed as 'inappropriate material, to build a boiler ? Surely that's what full sized original ones were made from.

If it was made from certified boiler plate and welded by a coded welder, why would it be inappropriate for a model. ?

[norman valentineParticipant @normanvalentine78682]

Because it is only about 16swg steel and would rust through very quickly.

[Nigel BennettParticipant @nigelbennett69913]

Looks about the right size for LC Mason's "Minnie" in 1" scale. Despite Alan's comment, I would think steel for a boiler of this size would be an odd choice. Unless there are proper material certificates and it was put together by a coded welder, you won't get a certificate for it.

Shame – all that work! If you make it as a static model, there's going to be a lot of investment in time to achieve that – and so I suggest that you make a "proper" boiler for it. Not something you can swop out easily on a traction engine…

[Alan Waddington 2Participant @alanwaddington2]

Posted by norman valentine on 12/12/2016 14:39:16:

Because it is only about 16swg steel and would rust through very quickly.

Ah,16swg, you didn't mention that bit !…..i think rusting through would be the least of your worries if you tried to steam that

Edit: Just had a look at your photos, and it looks thicker than 16swg, although the welding looks non too clever.

Edited By Alan Waddington 2 on 12/12/2016 15:30:09

[pgk pgkParticipant @pgkpgk17461]

Looks like he also forgot the backhead and throatplate stays..so perhaps never intended it to be steamed?

[JasonBModerator @jasonb]

Looks to be a Minnie Boiler and as you say about 16swg looking at the front end of the barrel

Is it actually welded or brazed as the backhead joints look a bit yellow.

J

[norman valentineParticipant @normanvalentine78682]

It is brazed throughout. The tubes appear to be copper. It is 16swg.

Backplate and throatplate stays could easily be added.

If I were to build a Minnie I would probably only steam it the once and then it would become a display model.

I had no intention of building a traction engine, I just bought the boiler out of interest.

[Michael GilliganParticipant @michaelgilligan61133]

Electroplate it with Copper … then no-one will know

MichaelG.

[waiting for the torrent of righteous abuse]

[HopperParticipant @hopper]

It might last for a while as long as you run it on distilled or RO demineralized water with suitable water treatment chemicals added. Plenty of full sized steel boilers out there running for decades without corrosion. But if it is brazed together with copper tubes up against steel, you may get electrolytic corrosion due to the different metals, so maybe not!

[norman valentineParticipant @normanvalentine78682]

Alan Waddington posted "Ah,16swg, you didn't mention that bit !…..i think rusting through would be the least of your worries if you tried to steam that "

I checked the original Minnie design and that used 16swg copper, so I think 16swg steel would be more than adequate.

I thought that I would search amongst my six, 4 feet high piles of ME mags to find the original articles by Mason. To my utter amazement vol 135 was on top of the pile! My search took all of one minute.

Well, it is definitely a Minnie boiler, I might add the missing stays and pressure test it, if it is ok I might go ahead and build the model, I have been looking for a project.

To keep costs down I would cast the wheel rims and any other suitable parts from aluminium

[pgk pgkParticipant @pgkpgk17461]

You could do a low pressure test now and submerge in liquid to see if it holds.

I'm impressed with folk who have home casting skills and toys. If I get that far with mine I was thinking in terms of getting plasma cut thick plate since the fronts will come from the inner 'waste' of the backs.

[JasonBModerator @jasonb]

Typical allowance on a steel boiler in the smaller scales is about 3mm for wasting (rust) ontop of the thickness that would hold the pressure. For example my 2" Fowler has a 5" dia copper boiler that is 10swg, the 2" ploughing engine I have castings for has a 6" boiler with 5swg thick barrel and thicker platework, both same working pressure. Metal rusts at the same rate!

You confirmed my thought sthat it was brazed, the braze material is more than likely to contain phosphor which is a no no on coal fired models as it reacts with the sulphor and weakens.

Copper tubes in a steel boiler are common on the smaller size models though mostly expanded in rather than brazed/silver soldered.

If you are just going to have it ticking over on air which is what most people do with a minnie then you only need it to work at 20psi so if it has no major leaks you could use it like that.

Edited By JasonB on 13/12/2016 16:38:20

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