Technical Lacquer primer problems. Cracking, peeling right out of the gun.

Ok, Here's what's going on. I live in Missouri, and it*****s here. It's been very hot and really humid. I primed a bare metal Bobber fender, and a steel gas tank, as well as a new plastic air dam for an off topic car. The tank and fender I used the premixed Lacquer you by at the parts store. This stuff,
http://www.oreillyauto.com/site/c/d...472_-1_114&keyword=lacquer&pt=N0472&ppt=C0171
On the air dam I used A good brand of primer (can't remember the brand) as well as a good brand of thinner and the primer cracked, and flaked off almost immediately, within a half hour of spraying it. I prepped the parts before I started. I've been painting for a long time, just not much since moving to this hell hole. I'm from CA. and never had this problem. Is it the humidity causing it? Remember I tried 2 different types of primer, as well as two different paint guns. One was gravity fed, and the other was an old favorite Binks that I use to do completes with. Here's some pictures of the air dam, the tank and fender did the same thing. I painted the Bobber parts first, then the air dam the next day. Most of the primer blew off with my air gun. Thanks, Dean

 

I use the old school way of mix it yourself, I myself have learned this lesson too, you'll need to get some hot weather thinner for lacquer. The mid temp stuff is prob what they had pre mixed, with our temp/humidity it'll do exactly what u experienced. Get the 90 degree plus stuff. Good luck sir. Flux

 

Humidity can play hell with any paint. Don't know why you would use that paint anyway

 

Is it just the paint that's making you angry? Really? Or is there something else that's bothering you.

 

What did you prep the surfaces with and are you painting over existing primer or paint? It looks like the new paint didn't like the old paint or what was there first.

 

The fender is bare metal, the tank is old lacquer on the bottom, and bare metal with a small amount of filler, and the front air dam is plastic. I've used this lacquer before with good results. I haven't used the premixed stuff before, but I used the premixed lacquer paint in the same brand with good results. I'm thinking it's the humidity causing this. I'm going to buy some plastic parts primer for the air dam and try that. As for the tank and fender, I'll get some different thinner and try that. I'm using this paint because I've used it before and had great results with it. The tank and fender is a freebee I'm doing for a friend at work, and I'm doing an old Watson style panel job on it with maybe some lace. I'm trying to use what I have, and grew up using Lacquer. Thanks for the advise, Dean

 

I think what is happening is this: The evaporation of the thinner is dropping the temp at the panel below the dew point, that causes the humidity to change into water droplets that hit the surface at the same time as the primer. In reality you are spraying a water covered panel. On a less humid day, your materials would work fine.

 

Move back to California.

 

we use to put a small amount of retarder to stop this problem in lacquer especially in humid climates. also stops blushing in top coat, this was before blended thinners, but it still works

 

That's my plan. Just going to take a little longer than I want it to.

 

I primed the plastic part with a SEM's plastic primer today and it came out fine. Hopefully paint it tomorrow. I haven't touched the tank and fender yet, but I was going to get some Lacquer retarder to use in the primer. Thanks.

 

x2 on adding retarder or using a slow dry thinner! the primer is drying before it hits what you are spraying. also painting early in the day will help too.
jim

 

What I like about Lacquer is I can mix it and let it sit, either in the gun, or pour it back into the can of primer, unlike catalyzed paint.. I tend to clean my gun now though, as the Missouri weather makes everything dry up. I paint a lot of small parts and like that option. That being said, can I add the retarder to already thinned Lacquer primmer? If not I'll just buy some more lacquer primer, and the retarder too.
The plastic parts primer worked great, and I was able to paint the air dam today. I did paint that with acrylic enamel with a medium reducer and a catalyst. It came out great! Thanks!

 

Maybe not allowing enough time to dry between coats?

 

I would agree maybe not enough time between coats, or maybe too heavy, and thinner is evaporating too fast before the paint can dry

 

Looks to me like you have a adhesion problem. Make sure you wash the panels before you prime with soap and water then with wax and grease remove. you might have to have to remove the primer and start over.

 

I am with you on the using lacquer primer. I have used them all and feel it works best overall . The only real problems I have experienced over the years is mixing brands of paints and thinners and water from the air compressor. Some work , some don't. I have learned to always use the same brand paint and thinner together.

 

Hey this guy knows his stuff.......Hi Matt

 

Thanks for the reply. I prepped the panels the same way I have for years, and it's always worked before. And I've used this primer, and thinner with good results before. I'm leaning towards it being the very high humidity. It's even humid here at 5 am when I get up for work.
I put on very light coats, and gave it plenty of time to setup, like I always have.
I went to drive my Roadster Saturday after letting it sit in my shop for about 2 weeks, and the clutch disk was stuck to the flywheel. I'm sure it did that because of moisture putting surface rust on the metal surface. The disk brakes on my wife's car squeak when it sits for a few days. You can see the surface rust on the rotors. It's been really bad this year.
I used to do body and paint for a living, now I just do it for myself.

 

Yes you can add retarder to thinned lacquer primer. Better to use hot weather lacquer thinner and add retarder if needed.

 

Thanks

 

Humidity wouldent do that. so the plastic part and steel parts did the same thing? And both had no paint on them before you sprayed them right?
Considering you said this happened right out the gun its not a over application or not enough flash time problem. This effect wouldent show untill there were multiple coats on the panel and the solvents on your first coat were trapped cracking through all the layers of primer so the solvents could evaporate out and the primer could dry.
As for plastic parts cleeing is very important because they have mold release agents sprayed in to the molds when they are made. those chemicals are oil like and wont alow paint to stick some times. Thats why you use soap and water then a wax and grease remover so you get off the water soluble and grease contaminants. also make sure plastic parts are scuffed good with a 3M gray or gold scuff pad and soap and water. Next spray a plastic adhesion promoter on the plastic part. Let it flash according to the cans directions. Then prime.
As for steel cleen the part with soap and water then wax and grease remover before sanding. You can actually sand the grease contaminants in to the sand scratches on the metal. Sounds weard but I've seen it happen where it only lifts on your sand scratches.
To fix this remove all the primer and start over. Personally i would use a good 2k primer lacquer is old school, dosent fill as well, and shrinks more them modern stuff

Hope this helps

 

Thank you. I did wash all the parts, as well as use wax and grease remover. The fender was bare metal, the tank bottom was old Lacquer, and the plastic part was brand new. Maybe saying right out of the gun was jumping the gun a little. The fender did have 3 coats of primer layed down on it over maybe 30 minutes. The tank bottom didn't get looked at until the next day and had 1 or 2 coats on it. All that primer has been removed. The humidity has died down for now, so I hope to get them primed by the weekend. I know the lacquer isn't as efficient as the new stuff, but it's what I like to use. The plastic part I'm replacing was painted for 10 years with lacquer, and held up well until a Raccoon decided to walk out in front of me on the highway. Again thanks for your advise, it's well taken, and I'm not disagreeing with you.

 

I don't have any experience spraying Lacquer but have taken plenty of it
Off at the shop I used to work. Every lacquer job had surface rust under all the paint and deep pitting. Did you apply any type of etch or epoxy product on the bare metal? Like I said I'm not familiar with lacquer so I don't know if it requires that or if it's direct to metal. The plastic part is odd since its painted with lacquer already.. I had the same thing happen with some PPG primer when I over applied it too fast. Hope it goes better next time around! I've been fighting tri-stages the past 2 weeks in Topeka spraying at 104 with a dew point of 78! Spraying PPG envirobase water none the less..

 

I shot some Duplicolor white over SEM lacquer primer a few weeks back and had something similar happen in a few odd spots. It wasn't overly warm or humid. I think I had too heavy a hand with the finish white coats. This was on the floor pan of my Ford.

 

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