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andrew30
Does paint go bad?

I had a quart of Benjamin Moore low luster enamel paint that I used to paint the basement bathroom below a tile chair rail. The walls were primed first using a Kilz primer

The paint looked good and went on easily, but is not drying. After 24 hours the paint is still very tacky. I have a dehumidifer running and the basement does not feel humid at all.

Above the Chair rail was painted using a latex paint that was dry to the touch the following morning. (approx 8 hours)

The date on the paint can was 2001

Thanks

jkirk
Re: Does paint go bad?

yes paint does go bad, over time it will and if stored in the cold or overly warm places it will, the bonding agents and pigment will seperate. you can tell if it looks like congealed milk in a cup of coffee, (not the same color but similar effect

ordjen
Re: Does paint go bad?

Andrew30,

Paint that is stored in a well sealed can with little air at the top will keep for years unless frozen. All good paints have mildecides in them, which helps keep them from going rancid. I have, however, opened cans of paint or sealers which had a lot of air in the can go really rancid. Smells terrible!

As to drying: obviously coolness and humidity slow down drying and curing of both latex/acrylic paints and oil paints.

Another factor that slows drying is the amount of tint in the paint. Was your paint a very dark color? "Universal" tints have pigment in a base of ethylene glycol, ja, kissin' cousin to auto anti-freeze. In fact glycol is in many paints, especially the ones that say you can use it at low temperatures.

Unfortunately, very strong, dark colors will often use as much as a pint of tint per gallon. This dramatically slows the drying/cure time. Behr recommends that you give one hour of dry time for each ounce of tint before re-coating. Latex/acrylic paints normally take a full month before being fully cured. The surface will not be wet, but will feel really gummy until dry.

Premature re-coating can actually pull the first coat off the wall, especially if the underlying coat of paint is on the slick side.

Amateur paint mixers often overdose paints with tint colorant. Not drying properly is one of the consequences. Also, too much colorant will cause the colorant to float to the surface and look streaky, with uneven sheen.

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