What does "blushing" in paint look like?

[bykr]

 I see lots of people referring to it on here and I'm not sure what it looks like.

[StevenGuthmiller]

Usually it's just an uneven "foggy" look.

 

 

Steve

[BubbaBrown]

Most of what Ive seen no matter what color when it blush's it turns white. Alot of or most times it will rub out at least for me.

[Ace-Garageguy]

It's a surface "fogging" or milky-whiteness that appears most often when paint is shot under high-humidity conditions.

It can be barely noticeable to almost opaque depending on a variety of factors. 

The photo below is a good representation. The area in the center has "blushed". As stated above, it will almost always be on the very surface of the paint (or clear), and will polish off with no lasting effect.

 

[DPNM]

Blushing occurs when water vapor gets caught between coats in humid conditions, as Ace said. The top coat starts to dry before the water vapors have a chance to flash off so they remain in between the two coats. It is recommended to use retarder in humid conditions to slow the drying time giving the water vapors time to flash off.

[Ace-Garageguy]

15 minutes ago, DPNM said:

... It is recommended to use retarder in humid conditions to slow the drying time giving the water vapors time to flash off.

True.

Which of course you can't do with rattlecan lacquers like Testors and Duplicolor.

In that case, when one coat blushes, wait for the solvents to flash off, and then just spray another coat as usual. This next coat (and subsequent coats) will most likely blush too, but after the paint is dry and hard, the blushing will almost always polish off the surface.

If your metallic blushes before you clear it, you can just usually clear right over the blushing and it will magically migrate to the surface of the last coat.

NOTE: I say USUALLY because SOME basecoats, if they blush, clearing over them just traps discoloration under the clear. This is mostly an effect of uneven metallic particle distribution and "laydown", which can also be caused by excessive humidity in the air, or uneven substrate temperature.

The only way to know for sure is to test the specific materials you're having trouble with BEFORE you paint a model you care about.

 

[bykr]

Thanks for the responses guys!