Por-15

[Jolly Amaranto]

Has anyone had any luck using this product to treat rusty body parts before painting?

[Dpmulvan]

I've used it on other projects and it works well but I wouldn't paint it over rust on my porsche. I would remove the rust totally epoxy prime and paint.

[Strygaldwir]

I put it on my car about 14 year's ago. The only place it has been an issue is on the gas tank. The top coating I put on just pealed off after a year or so.

I used it more to protect the surface than to cover the rust. I used phospho on all the rusted part before putting on the POR.

[bpu699]

Works great to prevent rust from coming back...

I wouldn't use it under anything that is visible that you need to paint...

[Gillies]

I haven't had much luck with Por15. Contrary to a lot of opinions, it scrapes off too easy on rusty metal or regular metal. Epoxy primer is the best bet.

[l_turn9]

the key to getting good results with POR15 is to follow the directions "exactly" and use the products they suggest to perform each step. POR15 is not intended to be painted over in the places normally visible. Under the car however, can be an area where POR is helpful - suspension, etc is all do-able. BTW, a thin film of rust is necessary for the POR to adhere to the surface. There's a chemical reaction that occurs and some rust is needed to make that happen. Actually I seem to recall POR15 having a product that will allow POR15 to be top coated is visible areas. But it's an additional POR product that must be applied to allow top coating.
But as with all paint products, following the directions and using compatible products is necessary to get the best finished product.
Good luck -
LarryT