POR 15 and cab undercoat questions.

[mvfd70]

I need a couple of suggestions. I've looked around on here and I think I've decided to POR 15 my frame. I've got a line on getting in sandblasted so cleaning is not a problem. My question is this: Do I use just the black POR 15 or do I need the topcoat?

My other issue is I am wanting to clean up under the cab. How in the world do I get the underoat off? I was using a wire wheel on it some yesterday and it wasn't coming off.

I think I've seen both of these issues mentioned before but after some searching (and frustration with dial up internet) I thought it might be faster to ask. Thanks for the help.