How To: Repair/Avoid a BLUSHING When Applying Flat Top Coat

If you have sprayed flat top coat on a cold or rainy day, you probably have seen a layer of frost appearing, as shown in these heart breaking pictures:

This is called BLUSHINGA milky appearance of a topcoat caused by high humidity where water condenses on or in the wet coating. This can be eliminated by use of heat or a slower solvent or retarder. (

It appears that temperature (<13°C) and humidity (>90%) are the two major contributing factors. I have done several things in the past and try to solve this issue.

Addressing Temperature Factor: Keep It Warm

Addressing Humidity Factor Method 1: Using Semi-Gloss / Gloss Top Coat

Spray a thin layer of semi-gloss or gloss should do the trick.  Note this is just a quick fix.  In my experience, applying another coat of flat afterwards will unfortunately bring back all blushing.

So, flat no more.

Addressing Humidity Factor Method 2: Using Mr Retarder Mild

This method works particularly well with Mr Color 182 (flat coat) and Mr Retarder Mild (retarder).  Simply prepare 182 for airbrushing as usual, and add a few drops of retarder to the solution.  Spray a thin layer should do the trick, and you should see any blushing gradually disappear while it is drying.

Now take a look at the result using Method 2 in this delightful picture:

I developed Method 2 not only to fix  blushing, but it also prevent the very issue from happening.

NOTE: As much as I want to brat about Method 2 being the perfect solutions, it is not. If in doubt, then for the love of Gunpla, FLAT COAT AT ANOTHER TIME.

[original posted: 2015.02.22]
[2nd version: 2016.11.23]
[this version: 2018.12.02]