Leave E-Coat or Sand it off and prime

[Smitty_67]

All,

I'm replacing some body panels on my car and was reviewing some of the progress photo's from a couple restoration shops. It looked to me that they were removing the e-coat even on the inside of the replacement panels and priming the panels. Is that necessary?

[Gearhead Dude]

If it's a true e-coat, leave it on for maximum rust preention. Some manufacturers paint their panels to resemble e-coat. Test yours by putting a Lacquer-soaked rag on the panel. If the coating loosens, remove all of it. Otherwise leave it on and scuff before applying the next coating.

[armourmark]

I have always removed the e-coat from the exterior panels. I have left it on things like floor pans, scuffed it, and then sprayed with raptor liner. If you are worried about it, just remove it. It's not worth worrying about for as long as you have the car. In my opinion, definitely remove from the outer side of panels.

[67speedfreak]

We always remove it. I have found rust under it.
Not worth taking the chance in my opinion.

Brian

[ProdigyCustoms]

Remove it, We DA it off the outer panel and light sandblast it off the jams for ultimate etch and adhesion.

[Smitty_67]

Good to know guys.. If you have any advice on the steps and products you use to prep the panel, that would be great.

Thanks

[JRouche]

On my car I completely stripped off all the old paint and primer, and I found two panels (left fender and hood) were replacements at some time, E-coat under the primer. And lemme say, it was a bear to remove. Some industrial paint stripper wouldnt look at it.

But... The coating is very thin. So all it takes is some abrasion during handling and storing before the panels get to us to break through and cause some un-noticeable rust spots. They are there, just hard to see, till you sand the E-coat off and see the dots of rust.

I imagine E-coat has two purposes. In the assembly line where they havent been banged around too much and the time on the storage rack is short they can handle the panels without much worry about rust.

Then there is the aftermarket use for repop parts where they have to take the long trip over on a boat. They either have to coat the panel with oil (messy) or E-coat it. But it gets banged around alot from the manufacturer to you. So every lil scratch and ding is a starting spot for air (oxygen) to get to the base metal and rust starts.

So yeah, Im with the other guys. Sand it off. Get to the bare metal.

And for post stripping I used a good cleaning with BOTH water borne wax/grease remover and a solvent based cleaner before shooting some epoxy primer, after all the metal work was done. Ummm, some decent rags are needed that dont leave bits and pieces.

Some guys use and acid based method. Acid wash with something like PPG DX 579 then etch primer the panel. Ive been down the acid road before and I prefer the epoxy path these days. Inert is the way to go IMO.. But Im not a painter so take advice from the experts. JR

[Smitty_67]

Thanks Everybody,

Seems I was making this more difficult than it is. E-cote, old paint, or flash rust bare metal, doesn't matter. Seems the advise is to get down to clean metal either by mechanical or chemical methods. Spray with a good Epoxy primer and I should be protected well enough to proceed with the body work.

[Hogshooter]

make sure you do not sand it too smooth, no finer than 180 for best adhesion.