Steel tank rust, how bad, what to do?

[Eric Sedletzky]

This is the stuff I use:

The primer is 1:1 with a 15 minute dwell after initial mixing.
The topcoat is 1:1 paint/catalyst and up to 25% reducer.
Wear a mask, this stuff is deadly!

 

[Still Kicking]

Actually, you CAN achieve an OEM factory spec finish if you do it the way I've oultlined.
They are using paint chemistry very similar ir identical to the products I use. An aliphatic linear polyester urethane finish is what they use over an epoxy DTM (direct to metal) primer. If you can find an 80% zinc dust 2 part epoxy resin primer even better.
Benjamin Moore industrial coatings used to have a zinc epoxy primer but it's not available in CA anymore, shame because it was damn good stuff for this application. It was the MEK in it.
I had a marine business and have been in the auto body and industrial refinishing business my whole life. I know this stuff.
One thing is none of this stuff is cheap. By the time you buy everything you need you could probably just buy a new tank and be ahead.
I already have the stuff laying around because I have left over from other jobs.

Yeah I know it's possible to do it with experience, the right materials and willingness to invest the time. Without those three, results will be variable.