Regulator Valve materials

Hi

I am just starting the boiler fittings for my 3 1/2" gauge pacific loco.

I have a lot of aluminium and a little brass / bronze.

Having short arms and deep pockets (!) I wondered if I could use the Aluminium to make the regulator valve which sits in the boiler. There are no brazed parts on this - I am using a Southern Disc type design.

I expect there is a compelling reason why this is a bad idea - can anyone enlighten me please?

Many thanks

I doubt mixing aluminium with a copper boiler is a good idea due to the risk of Galvanic corrosion, aluminium and stainless is not a good idea unless you can isolate the two.

Bob

Aluminum and hot water/steam do not mix. Rapid corrosion can result, especially in contact with other metals as Bob mentioned. It gets even worse if there is any detergent involved (not likely in steam models, but I have seen some awful results in instrument washing machines and sterilizers in industry)

Bronze is the best choice for boiler fittings. Some people say brass is also OK if exposed to steam only, not used under the water level.

JD

Thanks guys. You have saved me a lot of hassle in the future. I will be hunting for a slab of bronze at the midlands exhibition on Thursday.

John,if you have a multi meter, try putting a bit of copper and aluminium in some hot water, select a low range on the meter and put one probe on each bit and see the voltage, probably about 0.5V

Ian S C

I've stopped buying aluminium cookware because of the way it looks when it comes out of the dishwasher, let alone the health risk of acidic food reacting with it.

Neil