Hot Rods Black ecoat - sand it before primer?

Should I sand the black ecoat before applying epoxy primer?

 

Like any surface, it should be scuffed to allow for mechanical adhesion. 180, red scotchbrite, etc. Scuff it, blow it off, grease remover, primer it.

 

Should it be shiny still after the scruff?

 

Shiny (and I typically like shiny bits) is the enemy when requesting a mechanical bond from paint. The hardener will provide a chemical bond, but you need to rough the surface slightly to make sure the primer has something to grip. Peel the back off a couple of 180 DA sanding papers, stick them to the palms of your hands and go "karate kid" on it. E-coating can clog the paper more so than primer, so I rub them together occasionally to clean them and make them last a bit longer.

 

Should the void created between the outer and inner fender panel also be sanded? Some of the area may be difficult to reach.

 

The "E-coat" (electro deposition primer) on the aftermarket parts is NOT E-coat, but only a "transport" primer, and almost all aftermarket sheet metal parts are cold rolled steel and have NOT been "phosphated" or have a phosphate coating on the steel like original (OEM) parts do.

If you are working on original factory (GM, Ford, Chrysler-etc) parts, then they are most likely actually phosphated steel with an electro deposition primer (E-coat). This you can prep like "Bandit Billy" says in post #2. If it's not actual "E-coat", I would sand it all off.

 

Every thing gets sanded

look up the tech sheets for the product you are using
Answers questions like this and more

test the “e-coat” with solvent. If it wipes off it’s just crappy black primer.

 

As noted above it is mandatory to sand/ scuff the e coat before anything is applied over it. I found that after having the body on my Comet e coated that sanding the underside of the body was the most difficult and labor intensive part of the build. E coat is very tough and it eats abrasive’s, but the work is worth it knowing the body has the best protection against corrosion.

 

After thinking about it over night I will take exception to my own post, MAACO somehow gets paint and primer to adhere to glass and chrome without sanding it! I mean really adhere! I don't know how they do it. For the rest of us, we sand.

 

The cheaper the material, the less picky it is

 

As commented above, if it's just transport primer it has to be removed because it is not etched into the metal and will fall off eventually - togethr with whatever was painted on top of it. That's what I did years ago when I used to restore cars for living - taking the risk wasn't worth it!

 

As an old guy who encountered this many decades ago, sand it completely or remove it. It has no adhesion qualities at all. Short cuts will get you.

 

Hopefully everyone is referring to the ecoat process and not electro static painting, sometimes the terminology becomes foggy and the meaning is lost.
Real e coat is a multi dip process and it is not sprayed on. The parts or vehicle is submerged in tanks of cleaner, rinse, and coating. Obviously it is more complex than my brief description.
Note the lightning bolt in the e coat tank picture below.
(Electrical charge)


here is my Comet body fresh out of the e coating tanks:

 

What solvent should I use to test the ecoat? Thank you for the help.

 

Lacquer thinner

 

Recently e-coated.

 

Friend of mine had a Cuda e-coated

interesting process.

coated inside and out

not cheap but try to duplicate it

 

Kabinenroller, where in S.E.Wisconsin for E-coat?

 

Restoration Specialists in Franklin. The shop is just West of where the Hales Corners Speedway once was, great people to work with.
414-529-1515
6846 S. 112th Street Franklin, WI.

 

Thanks!

 

What would happen if the EDP coating is not sanded and epoxy primer is applied?

 

The United Pacific fenders on my 32 Ford pickup came E Coated. We scuffed them with a fine Scotch pad and rattle canned them with gloss black Rustoleum XL. That was 10,000 miles and many high pressure car washes ago and they still look good. Show car? NO. It's a daily driver.

 

Risking an adhesion issue

could last forever
Could peel when ya un mask it

 

Sanding is always best when considering the risk of things not sticking and the cost of materials. I haven't ever considered not sanding something prior to primer or paint.

 

This E-coat shit is the the mortal enemy of good work. In my experience I don't give a fuck if you sand it with 80 grit. It's like mold release. That's to include even the shit you pay extra for from the stripping companies. Nothing duplicates proper catalyzed and inducted epoxy coatings. NOTHING. Fuck E-coat. Said what I said...

 

Can we get someone to post some pics? My kind of Hot Rod…killer fab work, I’m sure, and driver paint.

 

There’s one in every crowd….. and so polite.

 

How’s your Comet holding up? It’s because of your recommendation of the Milwaukee shop you used that I preached E-coat to my dad for his coupe.

 

I bought my roadster body from Speed 33 a long time ago, paid extra to e-coat the bare steel car before shipping. They dipped the entire car, deck lid and doors included. There is no bare steel on my car even in the crevices and places light will never shine. It was a no brainer as far as I am concerned. It stayed that way for years while I built the engine, frame, etc. In the damp PNW that steel body would have taken a lot of Gibbs to preserve it, as it was I didn't have to worry about it. Here is a pic oddly enough from May 2015, almost 10 years to the day.

Of course by the time I added hinges, cowl vent, etc I had sanded a lot of the coating away which was quite stubborn as I recall. But it did feather edge (kinda) as you can see in this picture of the cowl vent install.

Before paint I DA'd the entire car with 180, hand sanded the rest like inside the deck lid and jambs prior to epoxy primer, seam sealer and then high build to prep for paint. In areas inside the doors and under the dash where it was tough to sand, I left the e-coat and applied sound deadener over it which adhered quite well.

I will be long dead before this car sees rust or deterioration with or without e-coat. If I had a body dipped and they offered it, I would be tempted to do it again unless I was going to paint right away.

One more thought, on my 41 PU I finished last year it was sand blasted by the PO and epoxy primered and left that way until I took it on. The cab roof was so rusty I nearly had to blast it again but feared thinning the metal and warpage. A lot of sanding and rust mort saved the roof. If it had been dipped after blasting the metal would have been much nicer and easier to prep and paint. We never know when we start a project how fast we can finish it or IF we will finish it. I see it as a good protection against the unknown. To a shop owner like Highlander where the cars are being worked and restored on a schedule? Not in a million years. It is an unnecessary, expensive step that can negatively affect the finish. Everything we put on the body has the ability to ruin the finished product and that can be a loss of 10's of thousands of dollars.

 

Perfect, no issues. The shop that does my paint and body work has done numerous projects that have been e coated, he knows how to prep the surfaces. I worked with him every day for months on the car, I did quite a bit of the sanding on the e coat, it is very difficult to sand but it needs to be done or the top coats will fail.
There are no short cuts, as with chrome plating preparation be for primer and paint is more important that any other step.
I have had quite a few bodies e coated with no problems afterwards.