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Username Post: lacquer paint problems - HELP!        (Topic#84546)
captainkurt 
Member
Posts: 15

Loc: Highland, Michigan
Reg: 06-10-02
12-19-04 07:38 PM - Post#578941    

I am about to go nuts with a paint problem. Started this project years ago with lacquer topcoat... am just getting back to it now. I know, lacquer is old technology, but only the hood is left to do. Silver metallic lacquer over 1) epoxy primer, 2) feather fill and 3) regular lacquer primer.

After buffing I get cracks that appear in the color coat and seem to penetrate into the primer. Cracks are very thin, about 1-2" in length in random directions. They get worse over the weeks following painting. Have redone the whole job once, spending extra care to let everything dry well, didn't put paint on too thick, etc. Am about to lose my mind. Help?! What can I do to get this job done?!

 
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Gray Headed Mule 
"11th Year" Silver Supporting Member
Posts: 4732
Gray Headed Mule
Loc: Fort Worth, Texas
Reg: 12-11-03
Re: lacquer paint problems - HELP!
12-20-04 05:36 AM - Post#578942    
    In response to captainkurt

The only help I can give you is a site that is great for painting questions only! Although their is a Paint and Body forum on this site that I've looked at it may be your choice!
Here is a great site with lots of knowledge!
Paintucation Forum

The guy that owns the sight is Kevin Tetz. He is on the DIY channel on the show Classic Rides. He also painted the truck CopperHead that is on the show Trucks. Great guy great forum!
Mule

I'm sexy and I know it!

My 49 Chevy Fleetline Deluxe Restoration Project


 
SAM_57 
Very Senior Member
Posts: 2945
SAM_57
Loc: Hampton, VA USA
Reg: 06-20-01
Re: lacquer paint problems - HELP!
12-20-04 06:02 AM - Post#578943    
    In response to captainkurt

Sounds like the under coat is not compatable with the top coat.
S.Pollard 57 Belair sport coupe 69 C/10 stepside (wife's) 84 Monte Carlo SS


 
Anonymous 

Re: lacquer paint problems - HELP!
12-20-04 10:33 AM - Post#578944    
    In response to captainkurt

HI Captain,

First, you do not want to put an epoxy primer over a lacquer primer. The lacquer is "too weak" for the epoxy primer to achieve its desired traits.

But, that is not the reason for your cracking.

The lacquer top coat dries by evaporation.
The enamel primers you are using dry by oxidation.

The lacquer top coat dried and sealed in the gases from the primers - trying to escape during the normal curing process.

Only fix is to sand it down to metal and start over - just use the epoxy primer first. Do any body filler on top of the primer - then prime, then shoot the color.

If you are hell bent on using the lacquer top coat - better give that primer a few weeks to gas off.....

 
cdmhenry 
Very Senior Member
Posts: 2358

Loc: Minden, NV.
Reg: 09-14-00
Re: lacquer paint problems - HELP!
12-20-04 10:58 AM - Post#578945    
    In response to

I advise an oven cure of 260F for 2 hours at full temp.

 
Rick_L 
Honored Member
Posts: 25673

Loc: Katy, Tx, USA
Reg: 07-06-00
Re: lacquer paint problems - HELP!
12-20-04 11:01 AM - Post#578946    
    In response to

BTO, you took the order of application from Capt's post exactly backwards from what I did. I interpreted what he wrote was that he had epoxy primer first, then feather fill, then lacquer primer over it. Looking back, looks like it can be taken either way. Also I see no "enamel" type primers here, unless the epoxy is considered an enamel?
I agree with your answer given the way you interpret the question.

With the order of application and materials as I assume them, it should have worked. However, something has gone wrong here - either there's a material incompatibility or a curing/drying time window issue here.

Sometimes when lacquer is sprayed over lacquer primer, the thinner in the topcoat will attack the primer and cause this sort of thing. It is sometimes called "sand scratch swelling", and somtimes there's little you can do to avoid it. Sometimes the application of a non-sanding lacquer sealer prior to topcoating, such as PPG DAS 1980 or 1987 will help. If a "slow" thinner was used, that might be a factor too.

To fix it, you have to sand down through the damaged area. You'd be well advised to use a more modern catalyzed paint system.

 
Ronnie44 
Senior Member
Posts: 9041
Ronnie44
Loc: Tampa Bay, Florida
Reg: 12-23-03
Re: lacquer paint problems - HELP!
12-20-04 11:33 AM - Post#578947    
    In response to captainkurt

All I can give you is my experience with lacquers. Right now all of my Classics have lacquer paint and I wouldn't have anything else for cars that spend most of their time in a garage.
With lacquer paint, and most other paints, there is a certain amount of "shrinkage" that takes place as the paint ages. Little flaws in the final sanding prep, that are not noticable after being painted, or for a year or so, will begin to show up. Depending on the color, it may take three or four years.
I have seen paint jobs that looked great for the first two years, and by year three you could see almost every sanding stroke, if the light was hitting it at the right direction.
I'm not saying that this is your problem, but rather saying something that I have seen before. Look closely and see if these might be undercoat scratches, instead of cracks.
I have only seen lacquer crack on finishes where the paint was put on to thick, without allowing sufficient curing/drying time between coats. On my '55, from the time the first coat of black was applied to the vehicle, until the last coat was applied was almost three months.
As I mentioned, this might have nothing to do with your situation, just my experiences with lacquer paints.
In memory of George K Fullam(Goodwrench) Died 31 Mar 2005

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Anonymous 

Re: lacquer paint problems - HELP!
12-20-04 12:15 PM - Post#578948    
    In response to Rick_L

Quote:

..Also I see no "enamel" type primers here, unless the epoxy is considered an enamel?





You got it Rick - I used "enamel" as the reference term for his system which was non lacquer.

I thought of sand scratch swelling - but when he said "crack" - I have seen this quite often on a job which was rushed through the shop, or as you stated - flash off or cure times not being followed.

It sure is a strange combo.

 
Rick_L 
Honored Member
Posts: 25673

Loc: Katy, Tx, USA
Reg: 07-06-00
Re: lacquer paint problems - HELP!
12-20-04 12:25 PM - Post#578949    
    In response to

Our language is wonderful in that we can express ourselves in many ways, and confuse ourselves in just as many.

Hopefully the Capt. has gotten some idea of what can help, or what question to ask next.

 
Anonymous 

Re: lacquer paint problems - HELP!
12-20-04 01:45 PM - Post#578950    
    In response to Rick_L

Yep, and the internet can compound the language issue at times - since its only one dimensional.

I think the Captain has an idea where to start. I just ran out and bought some Norton stock - I figure sandpaper futures just went up!

I can sympathize with him. Its gotta be frustrating to put effort into something you enjoy - then slowly watch it "do what it feels like doing" - unfortunately, not the desired result.

 
captainkurt 
Member
Posts: 15

Loc: Highland, Michigan
Reg: 06-10-02
Re: lacquer paint problems - HELP!
12-20-04 06:15 PM - Post#578951    
    In response to

Great ideas, guys. Yes, I can see that I'm in for a bit more work. What the heck - I enjoy working on the car. The order of the coats was epoxy primer on the metal, then the feather-fill, then lacquer primer. I let stuff cure a (very) long time in between steps. I all looks good until a couple of days after I put the color on. This got me thinking... maybe I should seal the lacquer primer with something. I'm in the Ditzler system, and see that they have an epoxy primer called DPLF. Located the technical data sheets online. They indicate that it may be applied over just about anything, including lacquer. There is a note that says the lacquer must be cured, then sanded. So I guess I'll let the lacquer cure, sand the damage out and try this procedure. Does lacquer cure in a couple of weeks at room temperature?? Any opinions about this course?

 
Coley 
Super Senior Member
Posts: 3973

Age: 71
Loc: Milledgeville, IL. 61051
Reg: 11-23-00
Re: lacquer paint problems - HELP!
12-20-04 06:19 PM - Post#578952    
    In response to

I was the longest holduot for using the new urethanes. For most of my bodyshop work I lacquered everything!! A lot of my experience with lacquer problems is on the older street rods with ther raised belt lines and raised detail lines on the cars. Lacquer is the worst for shrinking over years to "bridge" at these lines. I have since quit using lacquer of any kind. My 33 coupe took 20 years to haze crack all over the car but it has. All I use now is the urethanes......
Any man that thinks he is too old to learn new things, probably always was....


 
67SS427 
Ultra Senior Member
Posts: 12683
67SS427
Loc: Lawrenceville, GA, USA
Reg: 05-26-01
Re: lacquer paint problems - HELP!
12-20-04 07:20 PM - Post#578953    
    In response to captainkurt

You said you first put down epoxy primer on the metal and you're using Ditzler(PPG) products. That's good, but now you just discovered the DPLF epoxy primer? DPLF is normally the PPG epoxy primer to use, so I was just wondering what kind other kind of epoxy you used before?
I presume you used the featherfill over the epoxy to fill in rust pitting, sand scratches, or to fill body filler imperfections? That should be okay, but since it's like liquid bondo, if it's too thick, I could imagine it shrinking and cracking. I prefer to use a 2 part finishing glaze like Ultimate Glaze, etc.
If you're using Ditzler acrylic lacquer primer(Kondar, maybe?), it oughta work okay, but a urethane 2K primer/surfacer like K36 or K38 is much better. I like the K38, since it's higher build and sands nicely. It's not always necessary, but in your case, I recommend you do seal up the sanding primer, after you're done blocksanding, with DPLF epoxy primer reduced about 20% with DT reducer.
If you are using Kondar(DZ), you can also seal it with the epoxy primer.
If you are using the old DZL primer, then epoxy primer is NOT a compatible topcoat and should not be used as a sealer on it. And the recommended sealers probably aren't available anymore, so I wouldn't use DZL.
So, instead of using lacquer primer, I'd also recommend spending more for the better urethane primer and sealing with epoxy so you don't have to do it again.
You can still use your lacquer color topcoat, since you can spray lacquer over epoxy with no problem.
Steve F., professional resto work since 1985, http://smg.photobucket.com/albums/v159/67SS427/E xa...




 
Anonymous 

Re: lacquer paint problems - HELP!
12-21-04 02:06 AM - Post#578954    
    In response to 67SS427

Quote:

So, instead of using lacquer primer, I'd also recommend spending more for the better urethane primer and sealing with epoxy so you don't have to do it again.





Badda BING!

 
57_sedan_delivery 
Old as Dirt Member
Posts: 6720

Loc: Hog Valley, Fla.
Reg: 02-19-01
Re: lacquer paint problems - HELP!
12-21-04 03:09 AM - Post#578955    
    In response to Coley

Quote:

I was the longest holduot for using the new urethanes. For most of my bodyshop work I lacquered everything!!




You're not the only one, I still have lacquer primer put away but then again I still do DuPont Centari over it too.
Mike W.

Founding father Desert Classic Chevys in Phoenix, Az.

1957 sedan delivery 454 TH400
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1956 Chevy 3100 US Navy pickup
1959 rare GMC 100 fleet option 100 pickup


 
captainkurt 
Member
Posts: 15

Loc: Highland, Michigan
Reg: 06-10-02
Re: lacquer paint problems - HELP!
12-21-04 06:19 AM - Post#578956    
    In response to 57_sedan_delivery

Got it - urethane, then epoxy. Many thanks for everbody's assistance. Grandmother's car will roll once again! (maybe next summer

 
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