Painting over existing paint with bare metal patches

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PostPosted: Wed Aug 29, 2018 8:51 am
Hello all, first time posting here. I'm doing an '81 F150 restoration and have a cab that I'll be painting and swapping. The exterior paint of the cab is sun faded (no sign of clear coat) and has a few surface rust areas at scratches and dings. I was doing a little sanding and POR-15 yesterday and got a little carried away and sanded some of the surface rust areas to bare metal then sealed the bare metal with some rustoleum primer until I sand it off and shoot it with my epoxy or high-build primer. My plan was to rough up the existing paint with 180 grit and shoot it with epoxy primer, high-build primer and then ss bc. But if I only have smaller areas of bare metal can I just shoot everything with high-build primer and then ss bc or should I just shoot the bare metal patches with epoxy primer as needed and then top the existing paint and epoxy primer patches with high-build primer? I'm trying to keep costs down but don't want to sacrifice quality and have rust through. All of the body parts I've picked up have very minimal rust so I'm trying to gauge if I need 1 gallon vs 1 quart of epoxy primer depending on the method chosen. This is not going to be a show truck as it is my first vehicle to get my feet wet with restorations and I'm trying to keep my expectations at bay. I'm using summit racings' line of primers and paints.

Thank you,
-Paul

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PostPosted: Wed Aug 29, 2018 9:05 am
For restorations you are best to strip to bare metal then shoot two coats of a quality epoxy primer.

I am not a fan of Poor-15 as it gets to hard and doesn't expand and contract with the metal has temperature changes. This can produce cracks that allow moisture in.

Remember this is your foundation for all the rest of the painting.
1968 Coronet R/T


ACTS 16:31

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PostPosted: Wed Oct 10, 2018 10:28 pm
'68 Coronet R/T wrote:For restorations you are best to strip to bare metal then shoot two coats of a quality epoxy primer.

I am not a fan of Poor-15 as it gets to hard and doesn't expand and contract with the metal has temperature changes. This can produce cracks that allow moisture in.

Remember this is your foundation for all the rest of the painting.


Thank you, I've started stripping and have been going down to bare metal on the fenders. I will do the same on the cab but I was thinking that everything that is exposed to the elements I go down to bare metal but then right past the door opening feather the bare metal to existing paint as all of this section gets covered up with trim/carpet/dash&headliner. Do you have a good sandpaper grit guide on the feathering? Also, I read all over that 400 for the existing paint but it confuses me that I'm hitting the bare metal with 80 grit to prep for epoxy primer and only 400 for the existing paint for the epoxy as well.

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PostPosted: Thu Oct 11, 2018 9:02 am
Epoxy primer is a mechanical adhesion and needs some scratch to grab onto.

There are sticky posts at the top of the Body and Paint Section that address proper preparation and sanding grit choices.
1968 Coronet R/T


ACTS 16:31

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