From what I've read I wouldn't advise using brass for a boiler Dezinctification ( is that a word ? ) comes to mind But I am not a boiler builder Others will no doubt comment

Roy

Room temperature properties of CZ108 ("Common Brass", as per Kemp's Engineer's handbook, 1988, not BS2871 as I don't have access to a copy):

Annealed: 0.2% Proof stress: 125 N/mm^2, UTS: 355 N/mm^2.

Full Hard: 0.2% PS 550 N/mm^2, UTS 585 N/mm^2

Multiply "N/mm^2" by 144.9885 to get "psi".

I do not know the elevated temp strengths of CZ108. As already stated above, due to de-zincification it is unwise to use brass. If you do, life the boiler and keep accurate records of service life, ensuring full dry-down between uses, and don't try to use in public. It is probably unwise to assume a strength greater than the annealed strength of 125 N/mm^2 (18000 psi) due to annealing when soldering the sheet.

Regards,

Richard.

I'm confused by the replies that say not to use brass ? Mamod and Wilesco seem to spring to mind.

I think the explanation for Mamod, Wilesco and any similar, being made of brass is because you fill them up to a certain level to run for so long, bit like a steam Iron. Packed away dry. They are very small, low pressure and in the unlikely event of explosion would probably only injure the idiot abusing same and no-one else. Probably, the low danger level is reason that they appear to slip under the wire for Pressure Vessel Regs. The bigger capacity and very much higher boilers capable of real harm come under the regulations governing combined pressure/volume.

Water only boils @ 100C/212F @ 14.7psi(atmospheric) and as the pressure climbs so too has the temperature have to climb in order to continue making the hot water actually boil and produce more steam. If there is a sudden and serious burst failure of the vessel releasing all of the accumulated pressure of steam, the hot pressureised water is immediately way above its natural (100C) boiling temperature and will immediately convert to steam at around 600 times its original volume, hence the violent explosion and severe scalding of anyone nearby. I have recently read an account of a dodgy small soft-soldered boiler in a model boat which blew up about 100 years ago, I think it was at Kensington Round Pond. That was lack of water and interference with the safety valve. There have been a number of wrecked traction engines in years gone by and photos have appeared in old MEs.

John