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Matt coat leaving a white frosting
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New Zealand
Member Since: May 13, 2013
entire network: 165 Posts
KitMaker Network: 30 Posts
Posted: Sunday, October 27, 2019 - 11:56 AM UTC
Hi guys. So I had a bit of a disaster. I tried Mr. Hobby flat cote for the first time (not the flat base, this is a matt cote). It worked fine on a test bit but then when I tried it again on the model it dried leaving a white frosting all over it.

Is there anything I can do short of painting over it?

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Victoria, Australia
Member Since: June 27, 2010
entire network: 3,959 Posts
KitMaker Network: 35 Posts
Posted: Sunday, October 27, 2019 - 12:49 PM UTC
Hi Phil

not unless you're willing to strip the paint off, (be it by sanding or solvent) unfortunately.

Often this white frosting, as you call is a result of the paint not being wet enough, this could be caused by a number of things:
1. Too much air pressure
2. Airbrush too far from work piece
3. Paint too thin
4. Too fine a needle in the airbrush
5. Moving too fast over the surface
6. A combination of the above.

Ultimately the frosting is the paint drops drying in the air prior to hitting the surface, thus giving you a frosted appearance.

sorry to be the bearer of bad news

You could try a coat of gloss clear before reapplying the matt. That way the gaps between the droplets of the frosting will be filled by the gloss before you apply another coat of matt.

If you just apply another coat of matt, without first applying the gloss coat, you will, I believe make it worse, as matt coat is essentially a porous finish, and you will be just adding another layer of porosity, compounding the problem.

As an aside, before ever applying a matt coat to my models to finish them, I always gloss coat first, so that there is a non-porous surface for the matt to go on, assuming of course the surface isn't already gloss.
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Quebec, Canada
Member Since: September 14, 2005
entire network: 2,485 Posts
KitMaker Network: 480 Posts
Posted: Sunday, October 27, 2019 - 02:59 PM UTC
Hi Phil,
I had a similar if not identical situation with a OD Sherman, this past summer.
After coating with a matte varnish, the tank went completely white after the varnish

My thought at that point was what would dissolve the matte varnish without resorting to
stripping or sanding it.

I filled my airbrush cup with TAMIYA Lacquer thinner and applied a generous amount
without actually flooding the model and to my surprise 50 percent of the white

Waited an hour and reapplied more lacquer thinner. By the 3rd application, my OD paint
returned to normal all the white had disappeared and the finished matte surface was perfect.

Give it a try...should work for you too.


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Santa Cruz de Tenerife, Spain / Espaņa
Member Since: July 04, 2013
entire network: 1,288 Posts
KitMaker Network: 337 Posts
Posted: Sunday, October 27, 2019 - 07:57 PM UTC
I have heard people solving it with another coat of matt or gloss varnish (both versions were said to work...).

Before stripping the paint or varnish you could try any of these in a small and not very visible area. If you go the matt way, avoid the troubles that RussellE pointed.