Cracking and crazing paint saga

[Jamese30]

Hi All

I'm hoping someone can help here. I think I know what's going on but need some pointers. 

I have painted loads of cars over many years and never had this issue but recently on two kits and 1 rc car body I have had cracks or crazing in the paint appear a couple of weeks after finishing painting. The cracks gradually get worse and worse. 

On the two cars I used Halfords paint (same can and colour) over autotek plastic primer then a Simoniz lacquer. All were acrylics. The rc beetle had different paints but still the same Simoniz acrylic lacquer. 

I gave a good 15-20mins between colour coats and the primer had been applied days before. The lacquer was applied about 2 hours after the paint. It was a very hot day and the camaro was left to cure outside. The rc beetle body had about an hour between coats. 

Same cracking appeared on all. I'm thinking that this is obviously a sign of paint being applied over paint that hasn't fully cured and therefore lower coats aregassing and moving under dry top coats. I am also wondering whether the lacquer is destroying the paints by eating into them..??? Any advice would be greatly appreciated and how to fix(which I think is sand and restart?) 

IMG_20190828_172910 by j p, on Flickr

Camaro cracks 2 by j p, on Flickr

IMG_20190828_172935 by j p, on Flickr

Thanks

 

James

 

 

[64SS350]

I'm thinking one of two or the combination of both. 

I've noticed some paints have a window for re coat, you miss that and you have to wait 24 -72 hours.

I don't think I would consider clearing much of anything 2 hours after any paint job.

[Jamese30]

Thanks 64ss350

On retrospect I think I clear coated too quick although on the rc I clear coated about a day later. On the rc car the paint can still be indetented with a finger nail 2 months after painting. 

[StevenGuthmiller]

I used to have this same issue when using Testors Wet Look Clear.

I'm not 100% certain as to whether it was because of spraying the clear too soon after painting, or if it was the clear itself, but since dumping Testors clear, the problem has gone away.

I now use Duplicolor clear and have not had any issues.

 

The problem was exactly as you describe.

Very small cracks began to appear shortly after the clear was applied, and continued to worsen for weeks after.

 

 

Steve

Edited August 29, 2019 by StevenGuthmiller

[Jamese30]

Thanks Steve

That is exactly what has happened here. The only common paint in all cases was the SIMONIZ lacquer and the autotek plastic primers. 

I have since used the primer on another car without issues but I used a different lacquer. I also baked that paint (first attempt) in my home modified food dehydrator. 

Thanks

James

[Jamese30]

I assume as it is proper car paint I won't be able to strip it but will have to sand it?? 

[935k3]

If it is lacquer 91% alcohol will strip it but not the primer. Super Clean should work on the primer.

[StevenGuthmiller]

4 hours ago, Jamese30 said:

I assume as it is proper car paint I won't be able to strip it but will have to sand it?? 

 

3 hours ago, 935k3 said:

If it is lacquer 91% alcohol will strip it but not the primer. Super Clean should work on the primer.

Super Clean should work, but I'm not entirely familiar with the paints that you used.

In the case of automotive paints, Super Clean works it's magic by dissolving the primer and therefore loosening the paint.

In some cases it might be necessary to put a few scratches in the paint, in various places around the body, down to the primer to give it some places to get under the paint.

Once it has begun to dissolve the primer, the paint itself, being deprived of something to adhere to, will lift off in sheets.

The only variable is whether or not the primer that you used is susceptible to Super Clean or not.

Some flat paints are impervious to it.

 

Some primers are actually easily removed with alcohol if the Super Clean is ineffective.

 

 

This is how Super Clean can affect a multiple coat automotive lacquer paint job after a soak of a few days.

 

 

 

Steve

 

 

[Jamese30]

Thanks Steve. Sounds like I need to get some.  I am in UK so may be a problem as only Super Clean available over here is a car cleaner. 

Is there anything else you know works or would recommend? 

[stitchdup]

The simoniz stuff is garbage. None of their paints are any use for modelling due to the large amounts of thinners they use in every can. The simoniz may seem like a bargain when its in the large can but in reality the size is made up with more thinners than other brands. Your better off sticking to duplicolour. You can use brown dettol to strip the paint and just now its on special in superdrug (3quid50 for just under a litre)

[StevenGuthmiller]

7 minutes ago, Jamese30 said:

Thanks Steve. Sounds like I need to get some.  I am in UK so may be a problem as only Super Clean available over here is a car cleaner. 

Is there anything else you know works or would recommend? 

 

Now that you mention it, I believe that I have heard from other UK members that Super Clean is not available there.

In that case, you might be limited to trying either alcohol or brake fluid.

Easy Off oven cleaner might be another option to try if it is available.

 

My guess is that the Super Clean "car cleaner" that you referenced is a watered down version of the full power stuff that we get here, so it will likely have little effect.

Other less effective brands of de-greaser such as Purple Power or Simple Green might be available to you, but sadly, they are no where near as effective as Super Clean either.

 

I have heard that some guys swear by a product called "Testors ELO" paint remover as well, but I have no experience with it myself. 

 

 

Steve

[SfanGoch]

Testors ELO takes off every kind of paint and primer. I've been using it for years. Brush it on, but do not immerse the parts. It starts working in about 20 minutes. The paint begins to lift and you can use a toothbrush to scrub it off. Once the paint is removed, wash the part with dishwashing liquid in warm water.

[StevenGuthmiller]

1 hour ago, SfanGoch said:

Testors ELO takes off every kind of paint and primer. I've been using it for years. Brush it on, but do not immerse the parts. It starts working in about 20 minutes. The paint begins to lift and you can use a toothbrush to scrub it off. Once the paint is removed, wash the part with dishwashing liquid in warm water.

I will have to put your recommended solution to the test sometime.

I have tried virtually every main stream paint remover available at one point or another, except ELO, and settled on Super Clean as the easiest and most effective stripper to date.

I suppose that I never suspected that a Testors product would ever be "the best" at anything!

 

 

Steve

[SfanGoch]

Steve, I'll take 20 minutes and done with ELO over overnight, or longer, with them other products.

[StevenGuthmiller]

39 minutes ago, SfanGoch said:

Steve, I'll take 20 minutes and done with ELO over overnight, or longer, with them other products.

If I decide to try it, we'll put it through the paces.

My paint jobs usually consist of as many as 13 or 14 coats of automotive primer, lacquer and clear!

 

 

Steve

[ewetwo]

I had a chevy I bought with a green paint in Super Clean for almost 2 weeks before the paint came off. Same thing with Purple Power. Some strip easily. Some not. I'll look into Testors ELO and give that a try. I didn't notice in Hobby Lobby. I'll have to try someplace or on line.

[Jamese30]

Thanks stitchdup I will try dettol - worst thing about the simoniz lacquer was it wasn't even that cheap - I was away on holiday and wanted to finish the paint on a model so bought it from a garage (ironically I never used it until I got home!!) 

Steve it looks like ELO isn't available over here either. So it is dettol or I might try IPA 99.9%. I've heard mixed reviews that brake fluid embrittles plastic so won't try that for the moment. 

I'm hoping none react with the revell filler as most of the camaro speedster shaping was done with that ?

[StevenGuthmiller]

34 minutes ago, Jamese30 said:

I've heard mixed reviews that brake fluid embrittles plastic so won't try that for the moment.

Unfortunately, I have heard the same thing about alcohol from some.

That's why I use it on a very limited basis.

 

 

Steve

[SfanGoch]

Active Powersports has it for $8.36.

JP, it's available on ebay UK.

[stitchdup]

On 9/2/2019 at 10:28 PM, Jamese30 said:

Thanks stitchdup I will try dettol - worst thing about the simoniz lacquer was it wasn't even that cheap - I was away on holiday and wanted to finish the paint on a model so bought it from a garage (ironically I never used it until I got home!!) 

Steve it looks like ELO isn't available over here either. So it is dettol or I might try IPA 99.9%. I've heard mixed reviews that brake fluid embrittles plastic so won't try that for the moment. 

I'm hoping none react with the revell filler as most of the camaro speedster shaping was done with that ?

Most of the paint removers will affect the filler mate,

[Jamese30]

Oh no..... 

I might opt for hand sanding the camaro then and try on the other body. 

[Jamese30]

OK so a while on but I promised an update. 

I tried a couple of mild cleaners to get the paint off the camaro but with it being car paint it wouldn't budge. Sanding it highlighted that the cracks were deep, and we'll into the base coat so sadly I played around with some weathering techniques for a bit then advertised the kit on ebay as part built and weathered, ironically where I initially bought it!! 

I will scratch it off as experience and be a lot more careful next time i paint a body I spent so long customising!! 

Happy modelling 

[kymdlr]

Thread bump. 
 

this is airbrushed splash paints lacquer base with a rustoleum lacquer rattle can clear. This clear is usually my go-to with no problems. The base was perfectly smooth. When I sprayed on the clear, it immediately started to wrinkle and finished with this. Any thoughts on what went wrong?

[Ace-Garageguy]

44 minutes ago, kymdlr said:

...When I sprayed on the clear, it immediately started to wrinkle and finished with this. Any thoughts on what went wrong?

Yup. The solvent in the clear was too hot for either the color or the primer, pure and simple, no other possibility.

This looks like a classic "why you don't spray lacquer over enamel" example.

Even though you say the Splash stuff is "lacquer base", there are different lacquer formulations, some of which behave more like enamels...and paint labeling for hobbyist and big-box/hardware store products is notorious for being inaccurate, vague, and confusing anyway.

Have you used this exact combination of products before with no problem?

If the answer is no, then this is why we constantly harp on testing each different combination before painting a model.

Edited December 18, 2023 by Ace-Garageguy

[bobss396]

I see guys in my club do this now and then. This is something I learned by age 11, using some of my dad's touch up paints from the garage. I used to speak up, but the cheap-paint crew poo-pooed my words of wisdom. Now I just sit back and enjoy the show.

 

Edited December 18, 2023 by bobss396
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