Boiler barrel

[Peter Simpson 1Participant @petersimpson1]

The boiler barrel on my 5" gauge BR Standard 2 has dimensions of 12" long, 4.5" diameter at the front tube plate and 5" diameter at the throat plate and is a true taper along it's length. As I do not have a set of rollers, would it be practical to purchase a 13" length of 5" OD copper tube and cut it down the centre line then form the taper over a wooden former ?

[Peter Simpson 1Participant @petersimpson1]

[Nigel BennettParticipant @nigelbennett69913]

Yes, you can do that. Likely to be a bit more expensive than the equivalent sheet material though. However, if you anneal the sheet first you can easily persuade it round a wooden former. Irrespective of which method you use, you will need a butt strap fitting along the joint.

[Paul LousickParticipant @paullousick59116]

Why such a big taper? Why not use a boiler without a taper ?

Boilers were originaly made this way because tthey were too long to roll out of 1 sheet. Instead they were made by rolling a number of shorter lengths with a slight taper so that the smaller end could fit into the larger end of the next piece and them rivetted tobether. (or are the BR boilers different to most others). I assume the boiler will be lagged and you won't see it anyway.

Paul.

[ZanParticipant @zan]

Paul So u would need a barrel at the diameter of the smoke of size meaning a reduction of size and water capacity at the firebox cleading  would still need to be tapered for correct appearance and possible problems with top feeds ad s valves

I understood the taper was about improving water circulation and reducing the diameter of the smoke box to allow even a short chimney to be within the loading gauge. Plus various other thermal issues

edit…l blasted autocorrect!

 

Edited By Zan on 27/04/2021 14:20:31

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