On my 98' were replacing the rocker panels and at the same time I will be undercoating my jeep. Its pretty rusty, rockers and lower quarters are eaten away but the underside is pretty rusty but no holes or anything terrible. So, I plan to wire wheel the whole underside and then what should I clean it with? Then, should I coat the underside/wheel well parts that aren't rusty with primer before pro 15?

 

por 15 is made to go on top of rust and seal it in. so if you've got a rusty frame and don't feel like stripping it bare, follow the instructions on the back of the can and brush on some por 15. if you're going to clean your frame really well then there's probably a better more durable undercoating out there.

 

Like said por15 will only stick good to rust anything else it will act like paint.As far as undercoating you can use the oem rubberized kind or go nuts with truck bed liner.

 

What about the por 15 metal prep? Will that work on paint, does the and everything to need to be off the surface?

 

Bump

 

POR 15 over paint, no. Metal prep helps por15 adhere to new or smoother metal. For a rusted underbody I would wire-wheel it to get loose rust and old undercoating off, clean it, then paint.

 

I think you all have been misinformed por15 is a 3 step process. Using just the paint won't work you still have to neutralize the rust. YouTube it i know from experience though.

 

Used POR15 on a truck bed. It had a few tiny rust spots. Flaked off after wire wheel prep. Sticked to just the rust if I remember correctly.

I used spay can undercoating on my XJ with no prep and it has held up amazing so far. Just pressure washed it, let to dry, before I used it.

 

Meh. I think "3 step process" is their excuse to sell 1qt of acid/solvent for $25. Will it be best using the whole process? Most likely yes. I would recommend a POR-15 topcoat; however, as they are UV stable while POR 15 rust coating is not. (Not that the underbody sees much UV, but still a good precaution + extra protection)

 

And a heads up wear gloves and a long sleeve shirt that stuff don't come off skin its gotta wear off.

 

Yeah I know the stuff is brutal to get off your skin. So you guys think if the metal is not covered in rust(but still not new metL either) it needs the metal prep?