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Old 08-06-2004, 06:10 PM
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Epoxy on new panels

Can I use epoxy primer over the primer on new panels or should they be sanded to bare metal and primed with etching primer ?
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Old 08-06-2004, 06:50 PM
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yes epoxy will work on panels, just scuff new primer and shoot it
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Old 08-06-2004, 08:25 PM
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I learned something a few years back talking to an OEM paint engineer. He said they don't want the e-coat roughly sanded that each manufacturer has a set amount of mils they want for maximum adhesion and corrosion protection.
He stated they like to see a Grey scuff pad not a red because the Grey is finer and lite scratches put in the ecoat with very little taken off.
I learned scuffing with 180 and when done 80% of the ecoat was gone, guess I learned wrong!

Yes epoxy works great over ecoat.
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Old 11-13-2004, 03:45 AM
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Rule #1: assume nothing, buyer beware

Rule #2: do the research, get the facts on your panels

The coating on your panels:

"maybe" laquer based transport primer on slick steel, needs to come off,

"maybe" crummy thin cheap e-coat on slick steel

"maybe" correctly applied e-coat,

I've never found "good" e-coat on any Mustang imported panels.

Strip it, 80 grit it, epoxy it, atleast any areas that get abuse from stone chips, moisture, etc.
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Old 11-14-2004, 08:32 AM
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Quote:
Originally posted by red65mustang
Rule #1: assume nothing, buyer beware

Rule #2: do the research, get the facts on your panels

The coating on your panels:

"maybe" laquer based transport primer on slick steel, needs to come off,

"maybe" crummy thin cheap e-coat on slick steel

"maybe" correctly applied e-coat,

I've never found "good" e-coat on any Mustang imported panels.

Strip it, 80 grit it, epoxy it, atleast any areas that get abuse from stone chips, moisture, etc.
Why in the world would you want to "80 grit it"? If you strip it, you should be able to use 180 grit at the coursest, to get good adhesion, although I don't feel that it needs to be striped, unless there is damage to the e-coat. 80 Grit would be fine if you need to use it to strip.
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Old 11-14-2004, 09:44 AM
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Quote:
Originally posted by red65mustang
Rule #1: assume nothing, buyer beware

Rule #2: do the research, get the facts on your panels

The coating on your panels:

"maybe" lacquer based transport primer on slick steel, needs to come off,

"maybe" crummy thin cheap e-coat on slick steel

"maybe" correctly applied e-coat,

I've never found "good" e-coat on any Mustang imported panels.

Strip it, 80 grit it, epoxy it, at least any areas that get abuse from stone chips, moisture, etc.
************************************************
Lacquer transport:
never have seen it or herd of it! Are you thinking of Cosmoline?

Maybe correctly applied or crummy:
No mater what we do we cannot create a rust free metal and adhesion as good as manufacturer. Example Nissan is building an e-coat place in MS as we speak--a five dip tank process.

Bad Mustang panels:
Where you buying these from? I just sold 22 mustangs and have bought many panels from Year-one and worst I have seen is a ping ding. The year one 66 blue stang, all year one panels and scuffed and shot with epoxy. Quarter was wrecked two weeks ago when battery broke lose in trunk and paint was not falling off.

bwk

http://www.southernpolyurethanes.com...s/MVC-406F.JPG

Last edited by BarryK; 11-14-2004 at 09:49 AM.
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Old 11-14-2004, 10:29 AM
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Barry,
Ive seen some of this cheap Lacquer "transport" coating.
Ive NEVER seen it on panels bought from a resto house like Year One or Goodmark. But get some of your A/F collision repair panels. The last shop I worked at in Northern Iowa we did TONS of chevy truck cab corners and rockers(88-98).
Every once in awhile you would get a a part coated with a cheap coating that would wipe right off to bare metal with Lacquer thinner.

Looked like regular ecoat but put a rag with thinner on it

Ive bought more parts then I care for for my three 70 chevelles from Goodmark. Never once have I had a cheap coating applied to them. Just a good scuffing with 400 on a da sander then epoxy or regular primer surfacer...Eric
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Old 11-14-2004, 12:00 PM
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Yea, your right. In 1992 I bought a front header replacement panel for the 57 t-bird, Sure enough it had ENAMEL red primer on it!
Small company and NC and thats all they made was patch panels.
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Old 11-16-2004, 06:23 AM
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replies to my post

To adtcart: why 80 grit?
The PPG DPLF spec sheet calls for 80 to 180 grit prep on bare steel. It also call for minimum .75 mils to 1.5 mils dry film thickness.

The epoxy is a barrier "skin" on the steel, the epoxy adhesion to the steel is primarily mechanical, it grabs the "scratch", the 80 grit deeper scratch forms a stronger linked skin.

Actually, I use the grit that seems most appropriate for the area, ex: use a DA with 180 on the hood (less heat).
To be sure there are no thin spots, I lightly hand sand enough 80-100 scratches that: no scratches in the dried hood = no thin spots. I hand circular scratch lightly with (used) 60 on the edges for build.

To BarryK:
Go back and read the original question from "Gasser", it doesn't say what the panels are or who made them, that's why he needs to find out what they are coated with.
Unless like you, he is going to sell the car(s) when it's finished, then it's their rust problem.

Your comment about "the paint didn't fall off" after the accident: Epoxy (or good e-coat) is for rust protection not paint adhesion. It's applied to make the steel last longer, not the paint.

Transport primer, crummy e-coat and good e-coat all look exactly the same on a panel.
Haven't you ever wondered WHY imported Mustang panels are so cheap ($59 door skin, $59 qtr skin, $39 valance).
Their not going thru a 5 stage e-coat process at the Nissan plant you mentioned.

To everyone, my "e-coat?" test:

I don't trust the lacquer thinner rub test alone. Like I said, they all look the same on a panel.
I coat a small area of the panel with Jasco Premium Epoxy and Paint stripper ($8/qt Lowes, great product***!)
If the Jasco goes dry in 15 minutes and literally "pops" the ecoat off, it's transport primer or crummy ecoat.
If the Jasco stays wet and gummy (but the ecoat wipes off easy with steel wool cause the steel is slick) it's probably good e-coat.

***for stripping enamels, fantastic! After 15 minutes it pops off the paint in DRY sheets, use your shop vac for a no mess clean up.

Steve

apology to "Gassman", I told BarryK to read your question from "Gasser"

to many memories of the old Willys and Fiat AA/ "Gasser" days, they were insane cars....

Steve

Last edited by red65mustang; 11-21-2004 at 04:48 AM.
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Old 11-16-2004, 10:13 AM
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Re: replies to my post

Your comment about "the paint didn't fall off" after the accident: Epoxy (or good e-coat) is for rust protection not paint adhesion. It's applied to make the steel last longer, not the paint.

**********************************************
Glad you have it figured out, but this statement is totally wrong and tells me your just reading tech sheets as you don't understand what epoxy really does.
Glad you got it figured out.
Barry
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Old 11-16-2004, 05:21 PM
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Well... I use 180 to prep bare metal for refinishing. If you count on the depth of the scratches in the metal to tell you the thickness of the finish, you are going about it wrong. That only tells you how thick it is inside the scratches, not on the outside, where it will be considerably thinner, unless you can still see the scratches.

I am not a paint expert, but know what has worked for me for alot of years. I use 80 grit to remove paint, body filler, or metal. To me, the idea of removing that much metal for paint adhesion doesn't make sense.
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Old 11-16-2004, 06:06 PM
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im with the 80 grit guy, ive used disk grinders to strip paint, like to start with a rough surface to put my epoxy on , since the epoxy is a slow dry paint it flows in the scratches to bite better. i use a epoxy called tenemec,its the toughest stuff i ever seen, after being cured it just about cant be burnt off with a torch or blasted off, i like to put it on before i bondo then put a hefty coat after i dodo to seal it,then i start my urathane primer with my flowable finishing pudy.
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Old 11-17-2004, 09:18 AM
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reply to adtkart

I do agree with you, 180 grit is plenty of "tooth"/scratch to get good adhesion on bare steel, on the hood, roof, trunk, any area that doesn't get abused, hit with stones and is subject to chipping like door edges.

Heck! I'll agree with you more than half way. Strip the transport/crummy e-coat off a $59 Mustang quarter skin, sand the bare steel with 180, BUT, hand sand the lower rear section with 80 grit for more "tooth" for the epoxy to grab to make a more impact resistant stronger linked skin to resist the stones the tires throw. Yeah, you will get chips but less with the 80 grit sanding scratches.

If you strip off the the transport primer/crummy e-coat off a quarter panel skin, then lightly sand just enough to thoroughly scratch the bare steel with 80 grit, it would probably require a lab scale to weigh the steel you removed.

About the peaks and valleys on the metal scratch surface, 80 grit is the limit based on the consistancy and slow dry/ flow of epoxy to not have thin spots on the peaks.
If your worried about thin peaks, coat it again.
What you gained with the deeper scratches is more surface area for more epoxy to grab, to make a stronger skin.
I do spray enough passes on the panel that the dried surface has a slick, smooth, semi-gloss finish when dried to make sure the peaks are not thin.

So back to the beginning:
Are you sure it's good e-coat?
If not, remove it, sand it with 80 to 180 grit, apply .75mils to 1.5 mils of epoxy for a rust resistant skin to protect the steel per PPG spec sheet #p-196.

I use 80 grit to to get the strongest "mechanical" bond possible of the epoxy to the steel

Steve

Last edited by red65mustang; 11-19-2004 at 06:41 AM.
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Old 11-17-2004, 06:57 PM
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I use mostly 80 grit on steel and 80 or 180 on aluminum.

Take 36 grit to some of these cars out there
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Old 11-18-2004, 05:36 AM
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reply to sevt_chevelle

36 grit for bare steel epoxy prep! your kidding right?

Last edited by red65mustang; 11-19-2004 at 06:36 AM.
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