Conversation Between redsuperduty and Witty73

I figured as much. I did the underside of the cab yesterday, I brushed and then scubbed with a scotch brite till it was fairly clean. I had alread blasted it, so there wasnt much left, just some areas I was worried about. I learned alot with my first go around. I dont think I will be as picky with the blaster anymore, as this is a great alternative. I like the way the 520 leaves the zinc in the pits, just hope it doesnt have an adverse affect on adhesion. Oh, and the other one is concentrate on smaller sections instead of say the whole floor in this case to keep other areas from flash rusting. Over all though its a great tool, thanks again, I really value your experience.

Hey Witty, when using the 579 & 520 process on surface rust I don't get every spec of black out of the pits, probably like 90%. When the rinse water comes off clean I feel pretty comfy with puting epoxy on it. I do start out with a wire brush, then switch to a red scuff pad.
My black truck has sat out in the sun a few days this summer, nothing has ghosted or shrunk, let alone any bad adhesion. Black paint in the hot sun is certainly a good test on a prep job and my metal was very pitted. I think you will be in excellent shape after 2 or three scrub and rinse sessions on your cab.
Have fun & send me some pics of the progress!

First of all, let me say thanks for turning me on to that 520...great stuff. Im curious, when you used this process on your 78, did you scrub with wire brush and abrasives till all the "black" was gone out of the pits? I am dealing with some fairly pitted metal on the underside of my cab. Blasting didnt take it all out, so now I am cleaning with the 579 and 520. Im curious if you scrubed till it was all gone, or if you trust the epoxy to seal it in? Maybe I am being a bit anal, but I really dont want the rust to come back down the road. I apreciate any advice.