How much cleanup?

[air66stream]

I am replacing the rear floor of my 66 Overlander and I am ready to clean up the frame for the POR-15. The frame is in pretty good shape, but do I need to remove ALL the previous paint, or just get rid of the loose stuff? I started in with an air drill and wirebrush (not in this pic) which seems to clean it up pretty well. I guess I just need to know if it is really worth the extra effort to strip it to the bone. Thanks, TomE

[InsideOut]

It sticks (actually chemically bonds) best to raw &/or rusted metal. From their website:

POR-15® is a high-tech, high performance rust-preventive coating designed for application directly on rusted or seasoned metal surfaces. It dries to an incredible rock-hard, non-porous finish that won't chip, crack, or peel, and it prevents rust from recurring by protecting metal from further exposure to moisture.

and this from their FAQ website:

POR-15 APPLICATION PROCEDURES Surface preparation:
Rusted surfaces are best; seasoned metal and sandblasted surfaces are also good.
To coat smooth metal surfaces:
Use POR-15 METAL-READY to prepare surface before painting. Surface must be dry and free of grease, oil, or other foreign substances. Use of 'rust converter' products is not recommended as they may affect bonding of POR-15 to metal. POR-15 likes to adhere to surfaces with 'tooth' rather than smooth, glossy surfaces.

and:

Since POR-15® chemically bonds to metal, the underlying surface does not have to be sanded before application. As long as loose or flaking rust are removed from the surface, an application of POR-15® will not only cover up the rust and prevent it from spreading, but will also strengthen the underlying metal and seal holes by forming its own membranes.

If it's not touching the metal because of paint > it will not bond and "do it's thing".

Shari