Re: Boiler repair by plating

Tom:
You may be thinking of flame spraying. This method is used to build up worn bearing surfaces, like auto crankshaft journals for instance. The part is heated, and ground metal is blown into an oxy-accetylene flame and sprayed onto the part. Different materials can be used to provide the desired wearing characteristics.
This same method can also be used to spray aluminum or zinc onto steel surfaces for corrosion protection (similar to hot-dip galvanizing). I don't believe pre-heating is required for this material. Come to think of it, this might provide a long-lasting "silvered" smokebox coating.
I don't believe it would be suitable for building up a boiler plate surface, as the grain structure of the added metal probably wouldn't be desirable. Mainly, it would be near-impossible to get the surfaces hot enough and access inside the boiler would be more difficult than removing the defective plates and replacing them.
Still, it's a good thought and maybe there are other techniques that could be used.