Old paint- get a paint stirrer drill attachment and stir it with the drill for several minutes at a low to medium speed. With any paint there's going to be some separation over time. That's just the nature of paint. Old paint- if it's been.
A good rule of thumb with paint is, if you open it and it looks / feels fine (like when you stir it up) then it likely is fine.
In particular, an unopened can of latex or acrylic paint lasts up to 10 years. For unopened paints that are oil-based or alkyd-based, the shelf life could be up to 15 years. Additionally, chalk paint has a shorter lifespan from 1-3 years, and milk paint only lasts 1-2 weeks after its mixed.
If the paint has gone bad, it will look curdled like cottage cheese or overly thick like a pudding. If you dig out an old can of paint and you have either of these, it's best not to use the paint and dispose of it properly.
Unopened acrylic paint and water-based latex paint can be good for up to 10 years when properly stored. That means it hasn't been exposed to extreme temperatures and the can has a tight seal, as we describe in more detail below.
What happens if you use expired paint? If the paint has a bad smell, you'll be adding that odor to your walls. In addition, expired paint will not provide even color coverage, the finish may not be smooth, and the paint is more likely to crack or chip.
1) Repackage it. A simple and very effective way to store your paint correctly is to repackage it. Paint will always store better if it is in a fuller container in contact with less air. This will mean decanting the paint into a smaller container which can be done quickly and easily.
Since the paint has been sitting for so long, it's likely it has separated. You will have to blend the contents thoroughly with a paint stirrer for at least five minutes. Stir up the paint and then test it on a piece of cardboard. If the paint looks normal and goes on smoothly, then you're ready to start painting!
Just like rotten food in your refrigerator, there's usually a harsh smell that accompanies an old can of paint that has gone bad. Physical changes. You might notice the consistency of your paint has changed. There may be a “skin” on the surface or lumps that won't stir out.
Make dried paints liquid again with water
As acrylic paints are water-based, you can make these paints liquid again by adding water. Hot water is best for this, which you pour drop by drop into the pot. Then stir the dried paint thoroughly and wait for the water and dried acrylic paint to mix thoroughly.
While you may not love the smell of fresh paint, spoiled paint has a scent that's much worse. "Paint that is beyond its shelf life can develop a rancid, sometimes rotten-egg odor," says Edrosa. If you open a can and find either of these problems, dispose of the paint and buy new.
I coated an entire smelly acrylic painting with bleach and let it sit. Now, the smell is gone! I've painted over it with new paint and all seems fine. This solution saved me for now, but my advice is to take a sniff test before you work with old paint.
The number one rule in resealing a paint can is that the lid should always be put back on immediately. Be sure to clean the edge or rim of both the can and the lid to get the best seal possible. To achieve an air-tight seal, place a piece of plastic wrap between the lid and the opening of the paint can.
A can of oil-based acrylic paint that's been properly resealed can potentially last up to 10 years in storage. However, it's important to note that oil-based acrylic paint can dry out quickly if the can isn't completely resealed.
Scrape the raised area of the drip. Sand so the surrounding area is completely smooth. Re-prime and re-paint, making sure you feather the new paint into the old.
Most paints last one to two years in an open can. Latex paints can last an average of 10 years in an unopened can. Oil-based paint lasts up to 15 years in an unopened can. The paint goes bad by hardening or becoming rancid when air or debris gets into a can that isn't sealed well.
What to do if stored paint has separated. If paint has been stored in one place for a significant length of time it can separate to liquid at the top and other ingredients at the base. The paint, once mixed back together, should be good to go. So simply mix it together really well.
It depends on whether or not you stored it properly and what type of paint it is. Paint that has never been opened, latex or oil, will typically last about three years. If you store a can of opened paint in the correct way, it most likely will last a couple of years.
Oftentimes, people throw their leftover paint in the garage, and they assume it will be fine when they need to use it again. It can be a surprise when they open the paint, and it has gone bad. If you store paint properly, it is usable for around five years, but it is important to make sure that you do it the right way.