My clear cracked

[Sixx]

another long night of bustin' my ass on a model and then the clear cracks on me!!!!!!

I primed it with duplicolor sandable primer, painted it with tamiya laquer and clear it with urethane clear.....everything was looking great.....after the first two coats of clear, I added decals.....put it in the dehydrator to let the decals evaporate any moisture.........when i went to clear it with wet coats, the paint just cracked EVERYWHERE!!!!!!!

I just don't know what to do anymore, can anyone help me figure it out...

[gionc]

Originally Posted by Sixx

another long night of bustin' my ass on a model and then the clear cracks on me!!!!!!

I primed it with duplicolor sandable primer, painted it with tamiya laquer and clear it with urethane clear.....everything was looking great.....after the first two coats of clear, I added decals.....put it in the dehydrator to let the decals evaporate any moisture.........when i went to clear it with wet coats, the paint just cracked EVERYWHERE!!!!!!!

I just don't know what to do anymore, can anyone help me figure it out...

2K urethanic?
A pict of the disaster with the kind of crack would be useful.

If the uretane was a fast 2K may be the laquer under wasn't cured, it moved and cracked the rigid clear coat.

[cyberkid]

How long apart were the primer, color, and clear coats applied?
From what you said, it sounds like Gio is right...

[Sixx]

cyber,











here are some shots of it.....


I primed put in the dehydrator for a bit
painted, dehydrated
clear, dehydrated
decaled, dehydrated
then cleared again.....cracked!

each time in the dehydrator about 15 min. each
This was never a problem when spraying tamiya laquer with tamiya clear.

Another problem that my wife said could have caused it is I measured my clear, and reducer in seperate shot glasses before sucking them up into my airbrush jar (i'm using an testors aztec brush).

I had some of the clear mix left in the jar from when I shot the first few coats of clear prior to decaling.

While the car was in the dehydrator I started working on the interior and only placed a peice of index card over the seperate shot glasses with the clear and reducer.

by the time I was ready to suck them into the jar, the reducer had turned to an almost solid jelly. I scraped it out of the glass, cleaned the glass with laquer thinner and poured fresh reducer into the glass.

I mixed the clear that had been sitting in its jar in the air for about an hour or so, and the fresh reducer to get my mix, then I poured the new mix in with the remainder of the mix in my AB jar.

Could the air have caused the clear to harden?
Should I have used fresh clear to mix with the fresh reducer?
Could mixing the new mix with the remainder of the already mixed parts caused a problem?
Most importantly, from the pictures, is there a way of fixing this without stripping it completely?
Thanks a million
Derrick

[Lownslow]

looks like the clear prior didnt dry. you could cut the clear then reclear again but i would use something less abrasive

[Sixx]

do you mean wet sand it? or 600 grit dry? I'm not sure I know what you mean by cut the clear?

just cut the cracked areas and re- spray the urethane?

will the urethane even its self out on the clear that's already laid?
Thanks man for the help

[Lownslow]

Originally Posted by Sixx

do you mean wet sand it? or 600 grit dry? I'm not sure I know what you mean by cut the clear?

just cut the cracked areas and re- spray the urethane?

will the urethane even its self out on the clear that's already laid?
Thanks man for the help

600 would worki use 800 and 1000 to make sure i dont wreck it yeah the cracked areas only. thats the stuff i was refering to if it reacted once itll do it again when i get the scalies from laquer or urethane i spray with enamel

[Sixx]

i'm gonna try it, wish me some luck, i'll let ya know how it turns out later
have a nice thanksgiving! and thanks again for the help

[freakray]

That looks more like crazing than cracking to me, two completely different reactions. How about some clearer photos?

[Lownslow]

Originally Posted by freakray

That looks more like crazing than cracking to me, two completely different reactions. How about some clearer photos?

doesnt tha only happen when you spray hot paint on bare plastic

[Didymus]

You have a lot of variables there, but one thing is for sure: Tamiya lacquer (TS series) takes days to dry, and urethane two-part clear takes minutes. Lacquer also requires exposure to air. Those disparities are the most likely sources of the problem.

I'd try Lownslow's approach first, before trying to chemically strip the car.

Sorry to be the bearer of bad news, but I have tried to remove urethane clear with CSC and DOT brake fluid, and neither were successful. It's very tough stuff. (That's one reason I went back to clear-coating with Tamiya clear lacquer.) I did NOT try either lacquer thinner or a caustic lye solution. If all else fails, you might try the thinner (ASAP!) or either Drano or Easy Off.

I really hope this project works out for you. Happy TG!

Diddy

[Sixx]

yeah, i hear ya Didy, i've sanded it down, being careful of the decals, I'm gonna dry it and make sure the gases are out before trying to clear it again! I'll let ya know what happens......you too man, have a good TG
i'm sure my wife doesnt feel like listen' to me whine about my car all day....i do owe her that
i'll catch ya later, thanks for the help

[freakray]

Originally Posted by Lownslow

doesnt tha only happen when you spray hot paint on bare plastic

No, crazing can occur when you have reactions between different layers of paint too.

[Decs0105]

What brand 2k clear did you use?

Finisher's for example says this for their urethane clear:
"<Caution> Will get spider webbing if overcoat AFTER 24hrs."

But I never had any problems with overcoating after 24hrs.!

[cyberkid]

Originally Posted by Sixx

I primed put in the dehydrator for a bit
painted, dehydrated
clear, dehydrated
decaled, dehydrated
then cleared again.....cracked!

each time in the dehydrator about 15 min. each
This was never a problem when spraying tamiya laquer with tamiya clear.

It sounds to me like the paint isn't dried enough...
15 minutes basically is not enough. The reason why it worked when you used Tamiya before is that these are all synthetic lacquers, with won't give you incompatability problems.

You used 3 different medias without letting them cure, thus creating this reaction...
I let my coats cure in the dehydrator for at least 12 hours before a second coat. Up to a week if its Tamiya clear.