Questions about boiler repair and coating.

Hello,
Does anyone know what welding certifications one needs to perform FRA compliant maintenance on a boiler? I have heard about building up boilers by welding. Could someone give me a general opinion of this method of boiler repair? What about riveted patches? Wouldn't you have to worry about rust between the patch and the surface of the boiler? Are they even legal today? Are there any good resources for learning about boiler repairs?
I have seen that some railroads use coating on their boilers. Is this a widely used method of preventing corrosion? Is there any brand that is said work especially well?
Thank you,
John



Edited 1 time(s). Last edit at 02/10/2018 01:40AM by Steam Fan 492.