[hgs_notes]

I'm a boiler and pressure vessel inspector by trade. I look at 1000's of air compressors. I've never seen that particular brand, but if you find the metal nameplate on the tank it will show the year built and pressure rating, among other things. Sometimes they even have the thickness for the heads and shell stamped on them (that's a current requirement). Anyway, in my experience these things rarely rust out from the inside. There is too much oil carryover to the tank. On the other hand, if it sat for a few years with water in it, it may have pitted some. Easy enough to find out, just open one of the plugs in the side or bottom and take a look. The other trouble areas on these are where the feet are welded to the tank (sometimes they crack) and the fittings themselves will occasionally crack. After more than 15 years on the job, including 3 working at an air compressor manufacturer, I've only seen maybe 10-15 tanks that failed.

Your biggest concern with this unit would be finding replacement pump parts, but that can be solved by replacing the pump.