I keep reading about various paints that require 3 or 4 different primers; a self-etching primer over the metal, then a high-build primer, then a sealer primer, all before the color.

Then there are 2-3 layers of clear over the color (which may involve 2-3 layers in itself).

Is all this necessary, or is this just show guys trying to trump each other (I did 17 layers -- anyone doing 16 is a slacker!!)?
What was done 20-30-40 years ago?

Bob, who is SERIOUSLY considering just a primer/sealer and some synthetic enamel...

 

For a good long lasting job you need them all.
Self-etching primer cuts into the bare metal and it is hard, it provides rust prevention also. Without it rust could form and that would pop the paint off.
High build primer is to get everything smooth. It covers all the small sanding scratches and imperfections. You need to put it on spray a guide coat then sand the guide coat off. You will need to do this as many time as needed to get a smooth finish. I just did a tach cover on my bike and did it 6 times. This does not build up as you sand it off every time so the only thick areas will be in the scratches.
Sealer if you used any body filler it will show up in the topcoat as it sucks something out of the paint. If I had taken a pic I could show you just why you need it! LOL I don't need that crap! Then I sanded all the paint off. Sealer will not stick to bare metal or old paint very well. If you have no body filler you could get away without it but I would not.

The color coat is very thin and I mean thin on the new paints, you recoat in 5 min then can clear in 30 min. So once the car goes into the booth you can put 2 color coats 30 min later 3 clear coats and have the booth ready for the next car in less than 2 hours.

Best of all if you are good (I am not!) you can put the clear on wet and then never have to touch it with sand paper or polish and still have a finish that looks better than a new car.


In the old days paint was good for 4 years or so, today 10 or more with the same care. Old days rust formed on the surface and popped the paint off. Not a big problem with newer paints. Last to get the same finish with older paints you had to do a lot more work and it took a lot more time. lol

 

Well Bob, the choice is yours. Apply a sealer, a couple coats of enamel and call it good. Of course, that is assuming you are content with sanding marks, small nicks and dents, and want to do it again in a couple of years.

Actually, there are some bragging rights to the paint you use. Enamel is old technology. It is cheaper but doesn't have the 'staying power' of the newer urethanes. All newer rigs come from the factory with urethane paint.

Self-etch primer
Still used by many but has been replaced by a number of people with epoxy. Self-etch bites into the base metal and helps additional layers stick to the metal.

Epoxy primer/sealer
Keeps out mositure. Keeps in rust. Great stuff and about the best you can get besides a factory applied e-coat. When used as a sealer, it protects the old paint from the solvents in the new paint you are applying.

2K (hi-build) primer
Usually found between the your base primer (epoxy or self-etch) and your paint (single stage or basecoat/clearcoat. Certainly not a 'have-to-have' primer but necessary if you want a blemish free surface. Apply 3 or 4 good coats and then sand most of it off. Thats right. You sand most of it off. You sand until the high spots are even with the low spots. Gives you a flat surface.

Color coat (single stage or basecoat/clearcoat)
This gives you your color. Usually 2 or 3 coats are needed to get even coverage. Single stage simply means the color and shine (the clear) are all mixed together and applied at the same time.

Clearcoat
Applied over the top of basecoat to provide protection and shine to the basecoat. Two coats are the minimum. I apply 3 because, I sand off at least one of the coats. The sanding removes any orange peel or nibs (dust, bugs, & etc.). The sanding process gives you your paint (not bodywork) defect-free finish.

How was it done many years ago
Well, they applied a coat with a brush, sanded it flat and brush painted again. This was continued until they got a flat surface. By the way, a lacquer finish is sprayed on, sanded, and repainted. Just like the hand brushed days.

My perception
I've never heard anyone bragging about the 'number' of coats. I have heard bragging about the process though. Coats don't count. Workmanship does.

 

Thanks for explaining. Sometimes I get overwhelmed by the amount of money I'm spending on my truck. The thought of spending $800+ just on painting supplies blows me away.

Bob

 

Try $800 for a one color paint job on a motorcycle.

 

Ouch. I restored an old Honda 650 Dominator (NX650) a couple of years ago. Lightly sanded the tank, fenders, and side covers, then found some duplicolor that came very close to the original honda paint. Primered it, sanded the primer till it was really smooth, and used the rattle can duplicolor. Followed it with some rattle can clear coat. After a few hot summer days here in Dixie, I polished it. Came out real nice, for about $50 bucks in rattle cans.

Bob