Crackled paint coat

Tools, Techniques, and Reference Materials Painting and airbrushing
1

Just finished my first all or almost all airbrush model. I came out OK for a first attempt. I’ve learned a bit about thinning and masking and all the good stuff. Sadly, I also learned NOT to put the canopy on until after the final flat clear coat!

I want to ask about to problems that I don’t know the hows and whys of. When putting on a clear gloss spray can coat before decals, some of the underlying acrylic appears to have gained a grainy texture and some parts show a crackled spider like pattern. Since this coat was a rattle can, I know-I think-that it’s not my airbrush skills.

Any suggestions as to cause?

2

Yep - either the rattle can propellent or solvents reacted with your paint. I’ve had this happen before, normally when I get a little ham fisted with the clear coat or don’t shake the can enough to mix the paint and solvents. Next time shake the can twice as long as you think and try multiple, light coats vs. heavier coats.

Rob
Iwata Padawan

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3

Thanks! So your suggesting it’s a reaction between acrylic and lacquer? Would it be best to use Tamiya X-22 instead of Krylon Gloss?

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I use krylon rattlecans for gloss and matte over acrylic all the time. The key for me is to make sure the acrylic cures for at least 48 hours to prevent reactions…and shaking the cans an unreasonably long time. Your milage may vary.

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5

I airbrush my clear before decals, one or two very light coats is all I use. In fact they are just mist coats.

By the way, I found out the hard way that applying too heavy a lacquer coat over X series acrylics will crack the color coat wide open. If not right away then over time. I bet there is a bunch of lacquer thinner in Krylon paints. X series paints can be a little temperamental as to what goes on top of them, and or, to how it goes on.. IMO, if you shot the color in Tamiya X, then use X series clear. Plus X-22 is a good clear anyway.

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6

Thanks, I think that’s the way I’ll go in the future. Do you coat again after decals?

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Generally yes, it seals in the decals. And gives the overall look you seek.

Edit: By the way, you don’t have to seal with X series gloss only. Depending on your build you may want something less glossy, like X-35 semi or XF86 flat.

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8

I’ve had this happen too. It seems to be a couple of things from what I gather either experimenting or reading online.

  1. putting the clear coat on too soon. the underlying "color’ layer needs to really be completely dry and cured, and rushing this could cause problems
  2. A combination of 1) and then putting on too thick of a clear coat layer, or putting on multiple layer too quickly and heavily
  3. Apparently some combinations of acrylic (for the color layer) + other non-acrylic paints (for the clear coat) can have problematic chemical interactions and can cause problems.

I found in 2 cases, one of them required me to complete strip off the paint and restart from scratch. Not happy about that at all.

Slow is smooth, smooth is fast. Plus Chemistry…

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By the way, I found out the hard way that applying too heavy a lacquer coat over X series acrylics will crack the color coat wide open.

Had the same problems with this as well. Very frustrating.

At this point I think I’ll only stick with Tamiya clear. 3-4 coats, spread over a day or two or three gives a pretty good effect.

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10

I’m no paint expert like a lot of the folks here but I will say I’ve put too thick of coats on too soon and had bad cracking or spider webbing. No chemical reaction just too much paint too fast.