What should I paint this with before covering it? ('73 engine bay)

[TooManyProjects]

Hey All,

In the process of restoring a 1973 Mustang I'm doing some engine bay refurbishing.

With what should I paint the rusty portion of the shock tower:

Before spot welding in this inner fenderwell:

I was thinking of using Eastwood's Rust Inhibitor but I've read it can be fairly flammable (Post #5). However, I don't want to just cover over this steel without trying to protect it in some way.

The tricky part too is that a portion of what I paint will ultimately be painted to match the appearance of the rest of the engine compartment. So I'm concerned about putting some kind of paint/protectant down that won't work well with the final engine bay paint.

Thanks for your input.

 

[RUSTYNUT]

I've used the por15 products. It's availible here local and the eastwood isn't. Apply per instructions, after dry mark your weld areas and grind a 1/4" or so larger than holes. The exposed areas can then have the por15 primer applied. Paint as you want later. I never had it burn out of control, but I wait until it is dry first an take it back from the welds areas to cut down on contamination.

 

[TooManyProjects]

Thanks for the input RUSTYNUT. After doing a little more research I don't have reason to believe that either the POR15 or Eastwood Rust Encapsulator products are any more flammable than other similar paints. Yes, they'll burn when exposed to heat like that of a welder, but they're not going to spread like some sort of gasoline fire.

I'm thinking I might just pick up a small amount of both products and test them out on some scrap and see if they meet my needs. If I find anything interesting out I'll post back for others' education.

FYI, I found on the Rust Encapsulator page on Eastwood's website that it is "Heat resistant up to 400 degrees F." I wasn't able to find anything similar on POR15 (only a liquid flammability rating of 104 F).

 

[Platonic Solid]

My reinforced trunk mounted bumper support brackets ( LINK ) proved that dried Por15 maintains a flame quite nicely. Not that it's really that big a deal, but it really is overkill. For future repairs I'm just going to clean (Por15's Marine Clean) and acid etch (Por15's Metal Ready) the rusted area, then apply 3M Weld-Thru Coating ( LINK ). I had a bad experience topcoating Por15's primer with a non-Por15 primer, so I now only use Por15 on surfaces that will be topcoated with Por15 products.

 

[2nd Mustang]

I've used heat resistant primer on engine parts, brake drums and exhaust pipes before spraying on the regular high heat resistant paints. They have all lasted nicely.