Boilers

[John Harris 4Participant @johnharris4]

Any views on stainless steel boilers. Has been suggested by a fried, a coded welder, for a 5 in Shay? Was going to go down the copper route but this an attractive alternative as the intention was to leave the model bright metal.

[John Harris 4Participant @johnharris4]

Stainless Steel Boilers

[Brian HParticipant @brianh50089]

The first boiler I made, for a 5" Terrier was in aerospace certified 316 Stainless Steel and was welded by an aerospace certified welder.

It could not be accepted as there was no class for it, ( I'm going back many years). So I learn't my lesson and consulted the club boiler inspector before building another but things may be different now.

Brian

[JasonBModerator @jasonb]

You certainly won't be able to have it tested by a club inspector as the scheme only covers copper and steel. Speak with a professional boiler inspector and insurance company to see what the costs will be for design approval, initial and yearly testing and insurance.

[Speedy Builder5Participant @speedybuilder5]

I made one (Aerospace quality 316 ss in 1965 ) for a 5" Firefly, but never proceeded to insurance test stage as by then it was discovered that over a period of time (apparently) you would possibly experience 'brittle fracture' along the waterline between water and steam. I believe that Australia has a different 'take' on the subject. it was a bit of a sweat belting hell out of the backhead to form the 1/2" flange, firebox also but I did it with jab rock formers and a club hammer, cold. I did pressure test cold to 200psi and all was Ok. tube Joints were silver soldered, the backhead , barrel etc were argon welded by a coded welder.
BobH

[duncan webster 1Participant @duncanwebster1]

Austenitic stainless and (very) hot water are not a good combination, you can get pitting and stress corrosion cracking. I think there are grades of SS that would be OK but whether you can get them in small quantities/thin sheets is anyone's guess. As others have said, you're not likely to get a ticket from a club inspector, and to do it via an insurance comany as a one off would cost as much as a copper boiler. In any case, you want some cladding to keep the heat in, so make that out of SS and no-one will know.

[Thor 🇳🇴Participant @thor]

Hi John,

As mentioned by Bob other countries (Australia) may accept stainless steel boilers. This one is in "Duplex" steel, not 316.

Thor

[JasonBModerator @jasonb]

Plenty of stainless ones across Europe.

[Neil WyattModerator @neilwyatt]

Here are a few recipes

en.wikipedia.org/wiki/Materials_for_ressure_vessels

[duncan webster 1Participant @duncanwebster1]

Posted by Neil Wyatt on 14/03/2018 18:10:55:

Here are a few recipes

en.wikipedia.org/wiki/Materials_for_ressure_vessels

I don't think the OP was considering a nuclear fired boiler.

[Will Taylor 1Participant @willtaylor1]

Hi all, what’s the feeling about having a brazed joint on the boiler barrel. The joint is a butt joint and it’s also rivetted.

[Russell EberhardtParticipant @russelleberhardt48058]

Copper boiler? Silver soldering = brazing with silver alloy, that's normal.

Russell

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