Is this a good idea to Por 15 the inside of the actual fenders if black is your under color ? Does anyone do this or is there a different product better suited for inside fenders ?

 

If you use por-15 make sure you follow the directions to the letter, and use the prep's they recommend. If it's good metal (not to much surface rust/pitting) I'd probably just use a good black epoxy. My 2c..

 

I plan to paint my '55 firewall the same color as the car, so inside the fenders will be green. However my '78 was a black engine bay, and the bottom of the fenders had a little surface rust, so I used Por-15 on the fender/firewall. Looks sharp! Good luck!

 

I agree I'm doing all black everywhere underneath. The Olds 455 blue plus all the chrome I can afford really pops with the black.
Now my fenders are both pretty good (Texas car) is there a downside to Por 15 especially on a thinner metal like a fender ? The car is now in the Philly burbs lots of snow, ice, & salt. Not that my ride will be aloud out to play in it.

 

Why not? When I had my fenders off my POR-15 hardened up over the time and it was a Sunday and nobody was open so I use wheel bearing grease and applied a thin layer. This is like 15 yrs ago and so far so good.

 

The inner fenders are body color and should be done with automotive paint at the time of re paint. The fire wall and cowl are black.

 

I used the cleaner, and metal prep, then waited for a bone dry day in the fall. The bond is still holding great! One downfall is no UV protection, you could degrade the paint if it's exposed to the sun. Car show, hood open for hours, all that chrome bling reflecting UV rays... I put a coat of regular epoxy on after just in case.

 

I used Corroless primer and then body paint over that.

 

You can paint the Por 15 just follow the directions! I believe you just have to primer it before it fully cures

 

If you are talking about the inside of the fenders that is not seen, if there is any rust at all I used rust converter and then paintable undercoating in a spray can to cover. If it is a visible area either semi gloss black or body color. I also used this inside the doors, the trunk drops, and the back side of the bumpers to prevent any future rust and preserve the work I did.

 

That's really all I'm trying to do is prevent rust in the future. Now no one will ever see the inside fender and I'm thinking since this stuff was not around in 72 they really had no choice but to give the inside a quick spray of body colored paint. As long as there is no harm I'm doing it. I bet Mr 1972 GM guy would use it as well. Paint it on then top coat it with Por 15 Blackcote that's the stuff used to protect from the sun. Anything that will be exposed to the sun should be too coated with this stuff. So far so good I'm just not doing the hammer test they claim it withstands. Maybe if my daughter is swinging. Thx for all the feedback feeling better about it.

 

POR 15 is best suited for a rusted surface. Here's what happens when you apply POR 15 to clean steel:

 

Question... did you clean and pre-treat the metal as directed before applying the POR15 in this picture?

 

I didn't do the work. The kid I bought the car from did it but I wouldn't chance it. I don't care how lousy you prep for epoxy paint, it would never peal off in sheets. He painted the frame over rusty metal with POR 15 and the finish is bulletproof. I wire wheeled the whole frame and couldn't do anything except scuff it up. Then I applied chassis black over it becasue I didn't like the gloss finish of the POR 15. I understand they now have a product that is more of a flat finish.