Paint question

[ToddK]

I am undertaking some body work on the race car, and I need a little help here. There were stress cracks forming where the fiberglass flares were bonded to the steel fenders and the rockers. Rust stains were starting to appear in the cracks. I am finished with the metal and fiberglass work on the drivers side and will start the passenger side soon. The front fenders, hood, and trunk are all fiberglass. The rear fenders are a mix of steel and fiberglass. The doors, roof and front and rear panels are all steel. There was three layers of paint and a gel coat on the fenders that I sanded off. The hood and trunk only have one layer and it's in nice shape, so I don't want to have to strip the paint. I hit the bare steel doors with some self etching primer, and used a little body filler around where I welded up the trim holes. The fenders are a combination of bare fiberglass/gel coat/primer/and body filler. What is the best way to go about primer, block sanding, and painting all of these surfaces. I just want to paint with a cheap single stage Nason, but I want to make sure the paint sticks well. I will be putting on and removing stickers from this car. Should I do all of the bondo first, and then hit it with a primer sealer, and then a high fill, block sand, and then a sealer again?

[esty]

seal the metal with epoxy 1st...then bondo and move to the hi-build to finish it

the epoxy against the bare metal will keep moisture from penetrationg the plastic filler...that's how the pro's do it ...

[TobyB]

Esty's right- if you've etch- primed it,

now epoxy prime with the same system.

But bondo likes raw surfaces best, so hit the primer with some

400 grit if you need really good adhesion.

Then do your worst!

But I'd epoxy over all the bondo once you're happy with the surface finish.

I use Delstar for the same reason- shit's cheap, and easy to

bond to when you have to fix things.

t

[ToddK]

I picked up a gallon of nason 2K eurethane primer. The can says it acts like a sealer and a filler. The old guy at the paint shop says to just use this stuff and nothing else. Unless I hear differently, I will bondo up the small imperfections in the fiberglass I laid up, and hit the whole side of the car a few times with this stuff. It should seal it up until I get around to doing the other side of the car. Once the other side is done, I'll sand the hell out of it, hit a few more times, and sand it to 400 or so and then paint.

[Guest Anonymous]

Make sure you used a catalysed primer surfacer. The old style ones that use thinner as a reducer will open up a whole can of worm with all your repairs and bondings.

Have fun. I did my race car this year over the course of 3 weeks. Lots of work but man was it fun...

Before:

After:

[ToddK]

The primer I bought mixes 4 to 1 with a catalyst. No reducer. Your car looks great. I still haven't figured out the complete color scheme yet for mine. I'll start with all white and add to it later. I'm leaning towards just a couple of green stripes or maybe an old school Porche red and black stripe. I do like yellow and green thou, but it would be a little funky if it matched my other race car.

[Guest Anonymous]

The primer I bought mixes 4 to 1 with a catalyst. .

Perfect...that is what you need.

[esty]

the 2k you have is good for final building and blocking before paint but it will not offer any rust protection...you need epoxy under it, over bare the metal....unless you aren't concerned about rust

[ToddK]

You lost me on that one Esty. How can the metal rust if it's painted? Unless you are talking about the fiberglass bonding to the bare metal. Wherever there is bare metal from sanding, I treated it with etching primer. Today I finished up all of the metal, fiberglass, and body filler on the drivers side. I'll shoot the whole side of the car with the 2K primer in the next couple of days and start on the metal work on the passenger side over the weekend.

[esty]

everyone does things differently...you already used the etch which won't protect against rust....have you ever seen rust bubbles form under the paint....that's what i'm talking about...sealing the bare metal with at least 2 good coats of epoxy will ensure that doesn't happen

as i said each to their own...if i have a car that i don't want to worry about, i'll epoxy the bare metal, bondo/glass, etc if necessary then do my blocking and get the body flat with the 2k hi-build then, when it;s straight...flat, shoot the paint

i'm sure it'll work just fine for you....just not the best way to invest the money...IMHO..only

[esty]

sorry about the long copy and paste ...this is from the pro's....

etch primer is a lacquer primer with a small amount of acid in it to etch the metal..

There is absolutely no comparison between the two.. Kind of like comparing lacquer top coats of the 60's with todays polyurethane clears... Absolutely no comparison at all.. Off the top of my head are as follows

1. Etch is soluable.. it soaks up anything that touches it

2. cant get filler on etch, it soaks up the solvent and kills the adhesion

3. Epoxy is air tight... Completely water proof.. NO OTHER PRIME PRODUCT IN THE REFINISH MARKET IS WATER PROOF EXCEPT THIS

4. THE WORST MADE EPOXY WILL OUTLAST THE BEST MADE 2K IN A SALT TEST 4-5 TIMES LONGER.. WHOA

5. Best corrosion resistance hands down.. again remember etch soaks, epoxy seals..

6. Epoxy can be used from start to finish... Our resident builder Shine uses it only.. no 2k primer for him at all.. Cant do that with etch

7. Epoxy can be blocked, and you are still 100% sealed.. cant do that with etch.. cant block etch at all

8. Etch is a rip off, really when you think about it.. You are buying lacquer primer.. Who uses lacquer primer in 2007.. No self respecting resto shop..

9. Etch is not recommended to go over blasted metal, blasted metal is perfect prep for epoxy

epoxy will seal the surface, and is the only primer that is not porous. Epoxy will provide good corrosion protection because air and moisture can't get to the surface, say a paint chip or break in the paint, epoxy will protect. Not true of etch, if moisture gets to the etch layer, it can get to the metal. Same is true of urethane. The zinc chromate that etch leaves behind does provide some corrosion protection.

Epoxy - 2k should not be soluable with chemicals, and makes a great sealer. Not true of etch, and solvents from coats you put over it can be sucked up and soften it. In fact I think the softening is how its designed to work to provide protection to the metal.

Self etch needs another primer applied over it before paint, it can't be painted over, epoxy does not.

Epoxy has good adhesion and good compatability with most things you will use. Etch you have to watch compatability. Many have strict warnings against apply filler over, or over filler areas. Better make sure you use it properly and know what your using with it, if it will be compatable.

Icar when I started use to always recommend etch primer, followed by epoxy primer, and now believe they even changed there tune. I always just sanded and used epoxy and skipped the etch. I saw no need for it in most cases. The only place I seen etch somewhat regularily used was on aluminum. My opinion is just to make sure you have clean, sanded metal, and skip etch and get it in epoxy right away. No reason having an 1k product with acid and possible issues if not needed.

THe only advantage of etch would be it will etch and bite into the surface on areas that can't be sanded, and the acid will take care of small stuff like flash rust. I think etch is a bit cheaper, haven't really bought any for stuff I do, just used it before at some places I"ve worked. Since epoxy is 2k, metal temps should stay above 60 for awhile for proper crosslinking.

Here is the problem, first the paint companies will not just pull this product because it is so cheap to make unlike epoxy or 2k primers.( Its a big money maker) The next problem is acid etch works very well under lacquers and enamels (20 years out of date) but the product never locks down so if you sprayed a fender with acid etch and let it set two years, you could walk up with Urethane reducer and wipe off.

So what do 2K primers, base, and clears have in them urethane reducers!

So what happens is the urethane reducers melt the the acid etch and you don't know it. So depending how much sun the car gets

the "pinhead" type bubbles can show up in a week or 10 years.

The reason for the bubbles is when melted the solvent along with the air in the vinyl acetate that the acid etch is made of start rusting the top surface and soon a little bubble will show up, if you pop the bubble it will look like rusted water and if you blow on it, it will go to bare metal.

the epoxy seals off the surface from ANY oxygen (unless it's rusted through, and then it needs more than just paint) so it can't rust anymore

etch primer is old school, like lacquer paints and primers, they are outdated, and should be replaced with the newer, better technology.

(that was hard, I'm an old timer)

they also cause problems later on, if when sanding you accidentally expose the etch primer layer.

I skip it altogether, grind the bare metal clean, treat with metal prep solution, and rinse lightly with water (it should have a very thin haze of white residue when dry). then shoot the DPLF over that, and your ready to go from there.

I usually do the filler work on the epoxy, then hit it with the high build, block, seal again, and paint[/b]

[ToddK]

Sounds great Esty, but what is this stuff. I did most of my painting back in the day with enamels. What is epoxy primer? How do you mix it? What is the brand name? What is the difference between 2k epoxy, 2k high build? The stuff the guy sold me was about $100 for a gallon of primer and a quart of activator. The can says 2k urethane primer- superior 2k fill and holdout.

[donfjohnston]

(nt)

[esty]

Sounds great Esty, but what is this stuff. I did most of my painting back in the day with enamels. What is epoxy primer? How do you mix it? What is the brand name? What is the difference between 2k epoxy, 2k high build? The stuff the guy sold me was about $100 for a gallon of primer and a quart of activator. The can says 2k urethane primer- superior 2k fill and holdout.

epoxy is the current state of the art primer to go over bare metal to prevent rust...it's what it says, epoxy any place you buy paint can tell you about it and sell it...it's a 2 part product like your hi-build so you'll need the matching activator

the 2k hi-build is intended to be the last thing you use to fill sand scratches, pinholes, etc from the body work...when you have your body work like you want it, you shot a coat or 2 of your hi-build then start blocking it for flatness...i use a guide coat when blocking...the guide coat will let you see the hi and low spots when blocking the flat panels...if you break thru the hi-build, shoot some morte and block it again

bare metal

Epoxy

2K Hi-Build

Paint

[Derek]

I may have posted this question previously. . .

Since the resto of my '73 2002 will take many months and I will be stripping, banging, cutting and welding one small area at a time, what is the best way to seal bare metal a spot at a time?

I can't see mixing epoxy every time I need to etch/seal a small area. Can I just hit bare metal with a spray can of etching primer and then when the body (or a significant portion) is done in this manner- scuff it and spray with epoxy?

Will that impair the adhesion of the epoxy?

Help. What's the best strategy to keep my work from rusting before I can complete the metal restoration? I want the excellent sealing and adhesion that epoxy provides.

Thanks,

Derek