paint primer

I am dumb enough to know that if I don't get a good primer coat I won't get a good finish coat.
My primer is cracking and peeling. I feel like it is going on dry. Any suggestions???
Lacquer primer w/ 50-50 thinner.

 

Why are you using lacquer?

 

Is that the sand able lacquer primer surfacer? 50-50 sounds too thin to me. If it's going on dry your pressure may be too high.
Edit- I take that back. Looking at a primer surfacer I have used is a 50-50 mix. Using a siphon feed gun pressure should be 40-45 PSI. With a gravity feed gun should be 35-40 PSI.

 

If your primer is cracking and peeling its more than likely something on the metal or the prep work. also 50/50 seems a bit to thin. I use lacquer on my cabinets and don't thin nearly that much but auto might be different

 

This primer happens to be all that is available at the local flaps. The can actually says to thin 1 part primer to 1 1/2 thinner but that would make it even thinner.
After drying it feels rough but sands easily. I have put in too much time and money to mess it up now.
I want to have it primed and painted before assembly.
please feel free to comment.

 

Are you painting bare metal or a painted surface? Putting lacquer over some paints will make it crack and bubble/turn loose.
If it's painted try rubbing a spot of the paint with a rag wet with lacquer thinner. If the paint comes off then you can't use lacquer on it.

 

I would try to source something different than lacquer primer. I haven't used that stuff since the late 1970s.
The best primer I have used recently is a 50/50 true epoxy, specifically, Southern Polyurethanes #6700-4.
Strip down to clean metal, apply primer, then add filler and high build prime, then color of your choice. This stuff is the toughest material I have found yet. If your going to do the job right, this is a great foundation. They even have a U/V protected black that does great on frames with no topcoat.
-Donny

 

Another satisfied user of SPI epoxy primer here. Seems like epoxy primer is the favorite of hot rod builders. I got mine from the local SPI jobber - and he dropped off my order at my house.

http://www.southernpolyurethanes.com/tech sheets new/2013.2/epoxy 2013.pdf

The Transtar and Kirker epoxy primers are rec'd pretty often to. Or you can go to your local auto paint store and buy a name brand, like DuPont or PPG.

For a sanding coat, I would use a polyester primer.

As mentioned, lacquer is really old-fashioned stuff.

 

Finally used up all my Nason's 2 part epoxy. Called Southern Poly Urethanes, they sent me a catalog with prices and specs. and told me the nearest distributor or I can buy direct. Super easy to deal with. I will be using their epoxy primer soon. Looks like great stuff.



Dave

 

Thanks for the replies. Don't know why all the flaps here only sell lacquer primer.
I will switch to either polyester or epoxy.
I

 

Just make sure the primer you buy is suitable for a first coat over bare steel, or over solid original paint. Epoxy will do both. Amateurs usually pick epoxy, but shops seem to prefer etch primer which has less wait time to top coat.

Are you stripping this car down to bare steel? Or are you painting over old paint? If the car has been repainted once or twice, you should probably strip to bare steel. You can paint over solid original paint if you sand first, but it has to be a good base and not too thick.

Polyester primer is a sanding coat, basically a thin coating of bondo. Bondo is a polyester resin, with a talc filler. Polyester is not suitable as a first coat, but is used to get that super-smooth sanded finish. Epoxy is too hard as a sanding coat, and etch is not meant to be sanded.

 

OK, here is where I came from and where I am.
Having only done one other restoration ('48 CJ2, 225, Saginaw steering, disc brakes) I am for all practical purposes a novice concerning paint and body work. My sandblaster is worn out and money is not available to have it professionally done.
My jeep body had been painted once. Every place I could reach was DA sanded with 80 grit and/or wire wheeled. Places I could not reach were cleaned as well as I could. Bondo was used where and when needed to get a straight surface but not heavily applied. Rusted areas, and there were plenty, were either patched with new panels or sprayed with "Rust Converter" and then primed with Rustoleum "Professional grade" rattle can primer. Lacquer primer went over that and now I'm wanting to use a final primer before painting.
Is this a disaster or what?

 

I decided to finish with a Urethane primer.
Thanks to all who posted comments.
I will post photos when finished.

 

I would think the problem is the lacquer primer not playing well with the Rustoleum. Looks like a lot of elbow grease, sanding to make sure all the peeling paint is sanded down and then coated with some type of primer to tie it all together for the paint. Not sure what type of primer that would be, but just like there is Tie Coat primer for painting over POR15,so it will stick. A little research should turn up a suitable primer for the final coat. I think the lacquer thinner in the primer is lifting the coat of paint underneath it. I would probably take the peeling paint down to bare metal with 80 grit, feather it out with 180, and then 220. Then spray on a good primer to seal it all together. Before investing in paint make sure the primer has stopped peeling. When you go to bare metal, an etching primer will help the primer and paint get a good bite. There is urethane (2k) primer and epoxy primer. 2k is available in spray cans and fairly easy to use. Epoxy is great stuff, but expensive and mixed in two parts sprayed with a paint gun. Last for a long time but hard to sand so it has to be top coated with in a certain amount of time. Try some etching primer on the bare metal then 2k in spray cans, then paint over that. Hope this helps. Hard to know if more will peel up but hopefully once the lacquer thinner dries it won't cause any more problems.

Dave

 

You replied while I was replying to your post. I hope it works for you. That's what I was suggesting.


Dave

 

A quality 2k primer is the ticket. Gonna have to sand the lacquer off though

 

Agree, and

Also agree. I've found that the Rustoleum primer stays soft a long time, and comes off with lacquer thinner. Before you start sanding, try plain lacquer thinner in a spray bottle or on a rag (ventilation!) Guessing most of it will come off with no effort.

According to a body man on another site, coating with spray bomb paint is a good strategy for covering your work to keep it from rusting while you work on the rest of your body work. When you are ready to paint, wipe it all off with lacquer thinner, lightly sand, wipe with reducer and/or wax and grease remover, and shoot your primer base. But the spray bomb paint is a lousy base for anything but more spray bomb.

 

Spray bombs make excellent guide coat paint. Or 22 targets...

 

Thanks for the advise. When I was ignorant I was happier.
I would have never thought Rustoleum primer would need to be removed

 

depends on how long its been on. id start with sanding the laquer primer off and test a spot out,with some 2k. rustolem sticks good just dries slow. also a light almost dust coat of 2k may hold down without lifting spray a few with plenty of flash time between coats.