Put in new heater core that was leaking. With the carpet up I am going to sand floor pans and paint with primer/paint spray can. Here is my question: I was then going to brush on POR 15 followed by Dynamat. Any issues with laying Dynamat over POR 15? I woudnt think so but thought to ask. THX

 

I had no issues applying it on mine. I used the Killmat brand but it is all basically the same stuff.

 

Thank you Mudbogger2

 

Why primer if you are using por15? It likes a little rust to stick to.

 

Just thought it prudent to sand as much up as possible and then paint/prime. Is the POR 15 less effective over primer vs straight onto rust?? I know POR 15 does seek out water

 

Much better if applied on to the bare metal. Less chance of it pealing up. People have primed first I am sure, but on floor boards I wouldn’t think it is worth the time. I would sand it down to get the heavy stuff. You do not want a smooth shinny surface. The por15 needs something to bite into and hold. I have used por15 and KBS with satisfactory results. Only time will tell. Since it will be under carpet no need to top coat.

 

I've had horrible luck with POR15. Doesn't stop rust, peels off, costly, a pain to work with.

I would not use spray can products at all.

I use Rustoleum Rusty Metal primer, followed by a coat or two of Rustoleum enamel in your favorite color.

 

thank you again. You just saved me a whole lot of time and effort!!! Stay Safe

 

Yea, I stayed at a Holiday Inn Express last night.

 

POR15 is awesome when it's applied properly. I've used it for years, the rear axle under my Crown Vic DD has held up to being blasted with sand and salt in New England winters for close to a decade now. It needs to be applied to rough bare, or treated surface rusted, metal only. It won't adhere all that well to other paints, primers or coatings unless you really rough it up so it has something to bite onto. I'd use 36grit anywhere i didn't care about aesthetics and 80 grit where i did. Remove ALL the loose and scaly rust. No matter how good a product it is, if it's painted onto something that isn't physically attached to the vehicle anymore it won't last. Wash it with a caustic soap meant for degreasing, something like Purple Power or Super Clean. Neutralize any remaining rust and etch bare metal with a phosphoric acid solution, Ospho, Etch and Prep, etc.. Then 2 coats of POR15, 2nd coat once the first is tacky to the touch. That's their system but you don't need to use their products. I've done frames, suspension components, bottoms of floorboards, and axles and never had a failure.

Like any good paint job 90% of the work is the prep. Slapping the paint on is the easy part.

 

Thank you ‘73 high boy. Will follow your excellent directions !!

 

Correction. Speed-freak ‘78. Will follow your directions but thank you to all that responded !