Technical School me on primer?

The guys who taught me about body work came from the days of primer being primer.
Now there's so many flavors of it Im amazed.
Can someone give me a condensed lesson on what to use where, and maybe a bit of why?

Starting from bare metal going out on my current project.

 

i used self-etching primer from NAPA> It is supposed to be best for old rust that is not removed when an old car is sandblasted. It also prevents rust forming until you get it painted. regular primer will let rust form and then its off to the races again. But I am NOT an "expert", just my experiance with restoring junk.

 

Always a fan of epoxy primer....

 

Self etching primer is used on bare metal, before self etching primer they used muratic acid solution to etch bare metal.

High build primer goes on after the self etching primer to fill in the scratches and then a sander sealer goes on after that. Used for blocking or at least that is how I do it.

I still use lacquer primer because I still shoot lacquer. KISS baby.

 

Yup so far sound advice. Self Etching/Sealer on bare metal. Polyester filler primers are good, Upol, etc. Provides a good base for the paint. I have used Self Etching, then the filler primer and after wetsanding with 320 applied 5 Star Hotrod Primer. 400 wet sanded that then painted.

 

started using Z chrome rust defender
polly primer filler with tons of zinc made for bare metal applications
so far so good
excellent adhesion and sanding
here's a link check it out
http://www.clausenautobody.com/proddetail.php?prod=rust-defender

 

Etching primer is getting harder to find. My supplier no longer carries it - purely epoxy primer at this point.

So...I do any major bodywork and filler work before any primer - metal just needs to have good "tooth". Then Etching (or Epoxy). Next is fill primer, blocked, reapplied, blocked, etc while taking care of small issues with glazing putty. Depending on the paint, finished with 400 to 600 grit (different paint calls for different final sand). Once confident in the blocking, time for a sealer or tinted primer - especially if a fairly transparent or expensive paint (it's easier to get coverage if you start with a primer close to final color). Then final paint.

 

Lots of luck,

I cringe when they talk about metal prep and hosing down a bare metal body.

Yes There are so many different flavored primers but none taste very good. Then there are the brands who make great arguments why theirs is better than the rest.

 

I was going to say the same thing. Etch primers are going the way of the dodo bird around here as well just too many possible issues with compatibility if they are not fully dry before putting something over top. Epoxy is pretty much the only thing that get used around here any more.

 

Hope I'm not hi-jacking this too bad. I have just used epoxy primer then high build and there are a few small spots that I have sanded through the epoxy to metal when blocking. Do the small spots need to be re-epoxied or is the high build ok over the small bare spots. Thanks Bob

 

It depends on the high build. Some high builds state ok for application on bare steel. I normally keep a spray can of etching primer on hand for a quick hit for anything sizeable.

FYI - here's a link to the current project I'm doing. Bodywork, etching primer, high build, tinted sealer, base, clear...
http://www.jalopyjournal.com/forum/threads/1960-pontiac-catalina-project.948802/#post-10836756

 

Thanks. It is PPG Shop-line 2 part. I'll look at the data sheet.

 

Shopline needs etched steel. Pick up a spray can for small areas.

 

Thanks. flamed34

 

Big fan of epoxy for bare metal and as foundation for everything layered afterwards. Really big fan of SPI (Southern Polyurethanes Epoxy primer). Cost and performance are hard to beat.

 

I agree. Epoxy is the way to go. PPG dp epoxies are great, but a little pricier. SPI is my new go to, comparable product, half the price.

 

Epoxy will outlast any etch primer. Etch primer is a product of collision work where faster is better. I've been in the restoration world for a while and no one uses etch on a car they want to last.

 

I really like Clausens Rust Defender the All-U-Need primer they have is also really good. I only use etch primers in spot areas where i have cut through to bare metal. Other wise i use Epoxy for a good base over prepped bare metal.

 

More opinions to make a tough decision even tougher!
Etch is good for quick one or 2 coats of light primer then paint. Like on wheels, inside fins of valve covers, things that don't need any bodywork, but need to stick to the metal well.
Urethane high build primers are used for block sanding out imperfections, but usually need etch or epoxy under it. Same with high build polyester filler/primers like FeatherFill.
Most epoxies are used as either an adhesion coating, or for final sealing. Not for filling, or surfacing, or sanding out imperfections. House of Kolor (and Squeeg's) epoxy does it all. I use it all the time, for almost everything. You can shoot it over steel, aluminum, fibergl***, you can put body filler over it, and under it, it builds, and fills scratches and pinholes, sands easily (most epoxies do NOT), and is a sealer as well. All in one product!

 

I need same information only fibergl*** body. Is there a difference?

 

Primers have sure become much more complicated then in past years and knowing which one to use first takes some learning.

One day I saw a good friend of mine spraying primers and when I asked what kind he was using he told me and then I asked one more question and that was HOW MUCH does that cost!!!!!!!!!!

Around $150.00 a gallon!!!. And I thought paint was expensive.

Jimbo

 

Plain old primer gets a bad rap from a lot of youngsters today with costs not being a factor to your build.....
However, being (71) years old, and growing up using it, mostly left over stuff given to me from a friend, has a look that is the REAL original Hot Rod look
Yes it fades, and no it was never meant to be a final finish, but at my age and liking/remembering the good old days, this is where it is at...at least the way I grew up..
I realize this is not answering your question, but just looked like a good place to make this old boys statement !

 

A little twist on primers.
I've seen plenty of cars that supposedly had no filler,
10 gallons or more of hi build primer though to flatten them out.
I just shake my head

 

Well you would only need an etching primer on the metal parts of a gl*** body. I suppose if you had a copy of a corvette body in metal then you would need an etching primer.

Here is something about gl*** that I learned in a round about sort of a way. I knew a guy that had an old vette, like in pre '57 old vette. he could not get paint to stick or build or both. Turned out that on most of the upward facing the gel coat had either rotted off or had been sanded off. Do not sand through the gel coat unless you want to slather it with gel coat all over again.

Aside from that scuff it and hit it with primer sealer and color.

OK then now someone school me if you are of a mind to, and I am asking for good info not conjecture. This question comes up fro m time to time, can you shoot lacquer over epoxy primer?

 

Lots of good info here but i agree with asking the question about your car first.
Love your car? Want to keep it forever?
You can use lots of cheap stuff and get away with paint murder because its all underneath and its for sale!
But if your keeping that car then work out your low and high spots in metal work and lead and use as little epoxy, etch primer, highbuild primer and sealer as possible. Why? Because you want to use paint and/or clear coat in a certain (mm) thickness! Thats where it really counts.
Old school used to layer laquers super thick because of lots of rubbing out (wet sanding) after. They did 10, 12 coats of laquer paint man.
Eurethane painters now barely use coats of color because the clearcoat is the thing. Heavy clear coat to rub out all the orange peel.
But whatever paint or primer or sealer is going on be carefull with its thickness in (mm's). They all are stronger if you spray them on like the can says. Not too thin and not too thick.
Personally I have seen too thick EVERYTHING! And it shrinks and cracks.
Prep it good and spray it like the can says but do the real work in metal and lead! My 2cents.

 

PPG says Epoxy is what they recommend under the lacquer primer.
my question is, do you still need a sealer before top coating lacquer. I have never done this in the past and have never had a problem with lacquer. BUT, my first experience with the poly paint about 10 yrs ago when doing the engine compartment on my dads project we used a PPG poly base coat-clear coat with an epoxy primer on bare metal. one coat of primer on that and a quick sand with 400 dry before the black. Came back 2 days later and all spotty. I went back to my paint supplier (owner was a personal friend of my dad) and asked about it and the jack *** behind the counter said I should have used a sealer. "I blew my cork", I said you were the guy helping me through this and knew it was my first venture in this paint. Anyway it was ugly and I never use the supplier anymore. It ****s as he is the largest in the area.
Used a flattner in the clear and it helped, most cant see it but I can.

 

Lots of good comments on products. I've been painting since 1970, first as a hobbyist and professionally since 1995. There's one tip I'd like to share. SAND IT DRY. With the abrasives available today, the only thing I wet sand is the clear coat. Even then, only the areas where hand sanding is required, is where there's the danger of a cut through, (corners, body lines and inverted areas). The key to straight body work is good blocking skills.

 

The only time I have ever used a sealer on anything is when I was painting over some other paint. my understanding of sealer is that it is used to "seal" in the impurities that would bleed through your new paint. I can imagine on a firewall even if you took it back to bare metal that the metal would still have soaked in some solvents and oils over the years.

When I was still in the body shop with Lynn we used a lot of sealer and a lot of prepsol prior to shooting color. On an old car contamination is always a real problem.

I helped a body man some when I was in California during the Mediterranean Fruit Fly scare when the state was spraying a lot of malathion. You had to take the body back to bare metal, then pickle it with muriatic acid solution then prime and use sealer to keep that **** from bleeding through. Nasty stuff.

 

The other thing a sealer is good for is it gives you a consistent even colour to topcoat over and many can be tinted close to the colour you are painting so you may not need as many coats of paint.

 

[Q UOTE="SicSpeed, post: 10841220, member: 248313"]PPG says Epoxy is what they recommend under the lacquer primer.
my question is, do you still need a sealer before top coating lacquer. I have never done this in the past and have never had a problem with lacquer. BUT, my first experience with the poly paint about 10 yrs ago when doing the engine compartment on my dads project we used a PPG poly base coat-clear coat with an epoxy primer on bare metal. one coat of primer on that and a quick sand with 400 dry before the black. Came back 2 days later and all spotty. I went back to my paint supplier (owner was a personal friend of my dad) and asked about it and the jack *** behind the counter said I should have used a sealer. "I blew my cork", I said you were the guy helping me through this and knew it was my first venture in this paint. Anyway it was ugly and I never use the supplier anymore. It ****s as he is the largest in the area.
Used a flattner in the clear and it helped, most cant see it but I can.[/QUOTE] Back in the day, I sprayed a lot of lacquer, without a sealer. Everything was lacquer.... primer, color and clear. Damn it looked good, but we used a lot of primer, a lot of paint and a lot of clear. The old Binks and Devilbiss guns that were commonly used and higher air pressures put as much paint, (VOC's) into the air as they did on the car. Without a sealer, more coats of color are usually needed. For consistent high quality results and best color holdout using a minimum quan***y of paint, don't mix paint systems (all materials from the same line) and always spray a coat of epoxy sealer over primer. Or.......do it however you want. Cheers!