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AFV Painting & Weathering
Answers to questions about the right paint scheme or tips for the right effect.
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Why does thinned acrylic paint go bad?
Chrisk-K
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Maryland, United States
Joined: January 09, 2012
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Posted: Saturday, August 31, 2013 - 12:50 PM UTC
It seems that even when tightly sealed, Tamiya acrylic paint thinned with alcohol or Tamiya thinner goes bad after 3-4 days. Why? Anyone has a scientific explanation?
retiredyank
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Arkansas, United States
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Posted: Saturday, August 31, 2013 - 01:09 PM UTC
Only thin enough that you intend to use, that day.
didgeboy
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Washington, United States
Joined: September 21, 2010
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Posted: Saturday, August 31, 2013 - 01:23 PM UTC
I have had Tamiya paint that I bought over twenty years ago keep. Thin with water or windex and keep shaking it everyone in a while.
Chrisk-K
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Maryland, United States
Joined: January 09, 2012
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Posted: Saturday, August 31, 2013 - 02:43 PM UTC
Sure, I've never had Tamiya paint gone bad in its original form.

But once thinned, it goes bad in a few days. Case in point: I thinned Tamiya Dark Green with Tamiya thinner and sprayed it 4 days ago. After the painting session, about 1/2 oz was left. I stored it in a glass bottle with a Teflon liner cap. I spray it today. What came out of my airbrush was a green saliva-like liquid! Any chemist on this forum?
chumpo
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United States
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Posted: Saturday, August 31, 2013 - 05:14 PM UTC

Quoted Text

Sure, I've never had Tamiya paint gone bad in its original form.

But once thinned, it goes bad in a few days. Case in point: I thinned Tamiya Dark Green with Tamiya thinner and sprayed it 4 days ago. After the painting session, about 1/2 oz was left. I stored it in a glass bottle with a Teflon liner cap. I spray it today. What came out of my airbrush was a green saliva-like liquid! Any chemist on this forum?
what did you thin the paint with and what are you storing it in ? I have some mr hobby tire black thinned with Tamiya x20a and its been over six months and still good, it's stored in a mr hobby bottle . now they went bad when I use to use the testor's bottle, must be the cap .
didgeboy
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Washington, United States
Joined: September 21, 2010
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Posted: Saturday, August 31, 2013 - 06:10 PM UTC
Thick like a snot ball? Needs mor thinner and a good shake. Tis happens to me as well, usually as the thinner starts to evaporate.alcohol and lacquer thinner will evaporate faster than water or ammonia in a solution. Give it a shot or two of windex ad a shake and see what happens.
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