e-coat...... keep or remove?

[SUPERSTAR14]

Hi all,

I am just finishing up welding on quarters and roof skin, should the "E-COAT" be completely removed, hit with DA, or scuffed prior to epoxy primer?

Thanks in advance,

-Pat

[Ghoste]

Leave it on, its there for corrosion protection.

[myk]

Leave it on, its there for corrosion protection.

I am so excited about the e-coat on my new dutchman panel; in 50 years it'll be the only thing left of the car lol...

[Pete in NH]

Hi,

My take on it would be everything else you put on top of that E-coat will depend on how well that coating was applied. As far as  I know E-coat is just another way to say epoxy primer. So, at a minimum you would need to scuff it before applying another layer of epoxy primer. Like I said, if that   e-coat fails everything on top will go too. With all the labor and material costs involved in a good paint job, I wouldn't trust what someone else did at a factory where it may have been a quickie job just to protect the part during storage and shipping.Personally, I would strip it and know that it was done right.

[green69rt]

I'm not a painter but I always scuff anything before I spray it.   I've read several threads on here and, while all don['t say it's necessary, most do say to scuff.   Besides, it helps to clean up the area that you will be spraying.  I usually use around 150-200 grit, but I think up to 300 would work?  I've also left the e-coat on unless I suspect that something is wrong. 

On my new frame rails (from AMD), they came to me with such a bumpy finish that I stripped them and found the e-cat was applied over mud splatter!!

[Pete in NH]

E-Coat over mud splatter- so much for trusting the guys at the factory! 

[oldgold69]

you sure it was mud  or didn't the worker on the line get relieved for his break  or did he relieve himself before his break  do they get breaks in china

[Lord Warlock]

I'd definitely leave it on.  I'd wetsand it with 400 to 600 grit before painting it just to scuff the surface enough to ensure a bite to the new paint going on.  I'm only removing the coating on the trunk floor panels where i'll be welding it in, the rest i'll leave alone, then i'll re-prime the entire trunk area to prep for paint, not looking for a show finish though, it'll all be covered by a rubber mat anyway.

[mpd659]

I would sand it off, clean it, and spray self etch primer or epoxy primer over it. Then you know what have instead of having a problem in the future with paint. 

Russ

[Ryan]

For inside areas or underside areas I would scuff it then epoxy prime. For anything that will be finish painted I would strip it then epoxy. 

[Charger-Bodie]

For inside areas or underside areas I would scuff it then epoxy prime. For anything that will be finish painted I would strip it then epoxy. 

I agree.

[Silver R/T]

It's definitely not as good as epoxy primer. You can D/A sand it with 180 just to rough it up real well and then shoot couple coats of epoxy such as SPI. Wetsand epoxy and then you're ready for your color. These oem Toyota fenders came to me in e-coat and that;s what I did. I did shoot underneath with epoxy as well and then undercoated it.

[Lord Warlock]

Oh, i agree that epoxy primer should be sprayed as an underlay for color coat, but i don't think you'd need to sand off the ecoat before you primed it.  When i got a TA hood for my challenger I just primed over the ecoat (didn't even scuff or sand it first except a few imperfections/dings that were present when i opened the box).  180 grit leaves too many sanding marks for my tastes, 220 isn't bad, i've used it before and primer holds well and fills the sanding marks.  But I prefer to use 400 before color coating anything.

[Charger-Bodie]

If you have known ,good e-coat and the proper sealer to go over the e-coat It's fine. Just too much of a risk to take on a restoration in my opinion.

[Dino]

As with everything, if it has a shine to it you HAVE to sand it.  And as with everything that will see paint you need to degrease it before you sand it or you'll just spread out the dirt and sand it into the primer.

If you sand away a bit of the black coating, you will see the bare metal still has what looks like a clear coating to it.  The black is only a pigment and when just removed,  you will still have the coating on the part.  When a paint rep once told me this I was a bit skeptical so he said go ahead, sand all the way through it in one spot and take the just the color of in another and put it in the elements.  Well he was right!

If the panel needs no or minor work, I sand most of the black off but leave the coating in place.  If it needs metal work then I usually strip the whole thing.

[SUPERSTAR14]

Thanks for the advice, I've decided to remove it with DA then epoxy prime. I figure I can't go wrong doing it that way.

[Dino]

Thanks for the advice, I've decided to remove it with DA then epoxy prime. I figure I can't go wrong doing it that way.

That'll work!  And with a DA, you're still leaving the coating in place unless you are trying to shift the molecules in the steel.   

[bill440rt]

I will agree, on new OE parts the e-coat is an excellent barrier. Scuff it, and either apply a sealer or epoxy primer. It should be scuffed/sanded for proper adhesion. On aftermarket, Chinese parts who knows what the quality is of the e-coat.
The "clear" coating on top of the metal below the e-coat is zinc. It is best not to break thru the zinc coating or else you should apply either an etching or epoxy primer for max corrosion resistance.

[SUPERSTAR14]

Ok, so I decided to remove the e-coat from my AMD roof skin and quarters before epoxy primer......... Hanging the tin was way more fun! The e-coat was actually bonded quite well. It took more time than I expected to remove but still believe it is the "right way".  I would think on a car you don't plan to keep or one ya don't care about you could scuff it and  prime it. I figure I'm spending way to much on this project to take short cuts. At this point I only have myself to blame if the paint bubbles!!!!!!

-Pat

[elitecustombody]

Hi,

My take on it would be everything else you put on top of that E-coat will depend on how well that coating was applied. As far as  I know E-coat is just another way to say epoxy primer. So, at a minimum you would need to scuff it before applying another layer of epoxy primer. Like I said, if that   e-coat fails everything on top will go too. With all the labor and material costs involved in a good paint job, I wouldn't trust what someone else did at a factory where it may have been a quickie job just to protect the part during storage and shipping.Personally, I would strip it and know that it was done right.

QFT. I've seen numerous times e-coat fail on both OEM and aftermarket parts. I agree with Pete.Your final finish only as good as what's underneath it. Sand it all off and shoot few coats of epoxy for a piece of mind.

[bull]

You'd think if e-coat had an adhering problem it would have been reported and spread like wildfire to the ends of the world wide web. How many other rumors have you heard about "catastrophic problems" some nameless, faceless guy from Anytown had using Fram oil filters or F-body spindles or DOT 5? Anyone ever heard anything bad about e-coat screwing up a $20k paint job?

[green69rt]

I actually have no problems with it except some obvious crap.   I bought front frame rails from AMD that looked like they were dipped in mud BEFORE the ecoat was applied.  So obvious...   So the rails got stripped.  Other than that I chose to say that _ 1. if it won't show later then I will scuff and paint.  2. On outside paint I always will remove down to shiny metal an epoxy prime.  Just don't want to do the final paint job again.

[Dino]

You'd think if e-coat had an adhering problem it would have been reported and spread like wildfire to the ends of the world wide web. How many other rumors have you heard about "catastrophic problems" some nameless, faceless guy from Anytown had using Fram oil filters or F-body spindles or DOT 5? Anyone ever heard anything bad about e-coat screwing up a $20k paint job?

Yes but they can be spotted a mile away.  Years ago we had a plague of knock off replacement parts that had 'e-coat' which usually had a few runs.  When you sand it, it has a very distinct odor and leaves a weird residue.  That stuff had to go, all of it.

Never had a single issue with the good stuff but I have seen paint come right off when the e-coat wasn't at the very least scuffed.

[elitecustombody]

You'd think if e-coat had an adhering problem it would have been reported and spread like wildfire to the ends of the world wide web. How many other rumors have you heard about "catastrophic problems" some nameless, faceless guy from Anytown had using Fram oil filters or F-body spindles or DOT 5? Anyone ever heard anything bad about e-coat screwing up a $20k paint job?

Not going to argue, I'll just leave some pictures to prove that even OEM e-coat can ruin a $20k paint job


 




I can also post a few pics of e-coating failure on aftermarket parts, if you'd like

[Dino]

This and much worse is what I used to see as well.