Did you know that oil paints are considered good for up to 15 years and latex paints for up to 10 years? Most people do not know that there is no expiration date printed on paint cans. That being said, a good rule of thumb is that once opened, paint will typically last for 2-4 years. There are a few things that can cause your paint to go bad more quickly, though, such as freezing, mildew and drying out. So just how can you tell? The following information will help you determine if your paint is still good.
1) Has the paint ever frozen? If your paint has frozen and thawed multiple times it will begin to get chunky and no longer be good for painting.
2) Has the paint dried out at all? If the lid of your paint was not completely sealed the paint will begin to dry out. This will happen to different degrees; if there is a light skin on the top of the paint you can most likely remove this skin and your paint will be fine. Any more drying usually causes the paint to become too hard and chunky for proper use.
3) Has the paint been contaminated? If you have mixed water into the paint you have most likely introduced bacteria. This will cause the growth mold and mildew. Other things that can contaminate paint are: rollers, brushes, hands, or anything that may harbor bacteria. A good test is to smell the paint when you open it. If it stinks, throw it away.
4) If you paint has separated, don’t worry yet. Paint separation is completely normal; you should only discard that paint if it has separated to the point where there is a solid film on the bottom that cannot be mixed back into the paint. Otherwise stirring your paint will fix the separation problem.
5) If there are minor chunks (sand size grit) from drying or slight freezing, you can strain your paint through an old nylon or a paint strainer from your local paint store.
Remember, paint can have a very long shelf life, so proper storage is key. Make sure your lids are on tight, temperatures do not drop below 50 and not to introduce any bacteria into your paint and it should have a long shelf life.
Disposing Of Old Paint
If you determine that your paint is no longer any good, you can throw it in the garbage only if it is no longer in liquid form (throwing liquid paint into the garbage is illegal). You can harden the paint two ways, the first is to let it dry out naturally. This can take a long time though and needs to be stirred every couple of days. A quicker and more efficient way to harden paint is to use paint hardener. Paint Hardener will harden any latex or oil based paint over night. You can purchase Paint Hardener From Amazon for $2.47 (will harden 2/3 gallon).