When you examine a can of oil-based paint, one thing you will notice is that there isn’t an expiration date inscribed on the can. So do oil paints expire? Here is the answer to that.
Oil paints do eventually expire but the paint doesn’t expire based on an expiration date or a specific time frame. Oil-based paints expire based on the storage conditions of the paint. Generally, oil paints last over 20 years if stored correctly.
However, if the proper storage conditions for the paint aren’t kept, the oil paint will expire in a few years.
But that’s not all. This post covers more about the shelf life of oil paints. It talks about the expected shelf life, and how to revive old oil paints. So let’s dive in.
Can You Reuse Old Oil Paint?
You can reuse old oil paints because oil paints have a very long shelf life. But you need to ensure that the oil hasn’t completely separated from the paint particles and the paint doesn’t contain any lead before using it. As long as the old oil paint is in good condition, it can be revived and reused.
One amazing fact about oil paints or oil-based paints is that they take very long to expire. Some oil paints even last up to 30 years before they begin to go bad. This means you have extended time to use your oil paints.
So if you come across a container of old oil paint, there is a high chance that the paint can still be used. But there are a few signs to watch out for and a few things to do before using old oil paint.
For starters, you need to inspect the can. If the old oil paint hasn’t been opened previously, then you have less to worry about. However, if the old oil paint had been opened before, then you need to properly inspect the can first to check if it was sealed properly after use the first time.
If you notice the paint container wasn’t sealed properly and it has been in storage for years, toss the paint in the trash because nothing ruins paint quicker than air.
You should also check for lead. Lead is a dangerous substance that shouldn’t be inhaled or even handled. So check the container. If lead is one of the compounds in the paint, toss it out.
You should also check if the oil hasn’t fully separated from the paint particles. In most cases, when the oil has separated from the paint particles, the old oil paint is past its prime and shouldn’t be used.
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Do Unopened Oil Paints Go Bad?
Unopened oil paints do eventually go bad but this takes several years especially if the oil paint is stored correctly. This is because unopened oil paints when stored correctly can retain their condition for a very long time since moisture and air can’t get in the container.
Technically, unopened oil paints will go bad eventually. But if the oil paint is stored in the right conditions, it can take decades before a container of unopened oil paint begins to go bad. This is primarily because oil paints are thicker and thus less likely to cure in the container.
Oil paints due to the thick nature of the paint take several years to expire if left unopened. This is because the solvent used is natural or synthetic oils. These oils are less prone to room temperature, moisture, and even humidity than say, water-based paints.
The increased resistance of oil paints to moisture and room temperature makes it possible for the paint to last very long if left unopened.
Water-based paints for instance generally don’t last more than 10 years even if left unopened because the paint is thin and light. This means the paint can be easily affected by moisture, cool room temperature, UV rays, and the likes.
An unopened container of oil paints generally lasts between 20 and 35 years. Some might last longer depending on the makeup of the paint. However, if the paint isn’t stored correctly, unopened oil paint wouldn’t last that long.
So a huge determinant of if a can of unopened oil paint will expire or last is if you store it correctly.
Related Read: How Long Does It Take Acrylic Paint To Expire?
How To Know If Oil Paints Are Expired?
You can know if oil paint has expired by looking at the paint. If you notice that the oil (or solvent) has completely separated from the paint particles (or pigment), this means that the oil paint has gone bad.
When the oil separates from the paint particles, the paint will become dry and will begin to harden making it difficult to paint with. So, if you open the paint container or pour out the oil paint and you can see that the oil and paint have separated, the paint has expired.
But that’s not all. Some other signs indicate that oil paint has gone bad. Let’s check them out.
Mold Growth Inside The Container
You might not be able to check inside the paint container especially if the oil paint you have is in a tube. However, if it’s a can or a bigger container, you should inspect the container. If you can notice mold growth in the can, the paint has gone bad.
Mold or mildew is a form of fungus that appears in black patches in the container. Mold is usually caused when the paint is affected by moisture.
A Foul Smell
Mold is usually accompanied by a foul smell but sometimes, the paint will smell bad without mold growth. So if you open the paint constrained and you are greeted with a rotten smell, just toss the paint in the trash.
Oil paint in good condition would have a very strong chemical smell. The strong chemical smell tells you that the chemicals in the paint are still active. But if you can smell a rancid odor or a rotten smell, the paint has gone bad.
If The Container Is Puffed
A puffed paint container shows that the oil paint has gone bad. The container is swollen because gasses are being released by microorganisms (bacteria) that are eaten the oil paint.
If the oil paint container is puffed or swollen, don’t even open it.
If The Oil Paint Has A Different Color
Another sign is if the paint color is different from what it’s meant to be. Old oil paint that has gone bad might turn yellow or appear differently than it’s meant to be. This is usually caused by heat, moisture, and sometimes a foreign chemical in the paint before it was stored.
For instance, if you mixed the oil paint with another chemical or paint thinner while painting, it might turn a different color after a while in storage due to a clash and reaction of chemicals.
If you notice any of these signs with your oil paint, chances are the paint has gone bad and is unusable. But the best way to be sure the oil paint has gone bad is to: Test the paint.
To test the paint, carefully mix the old oil paint and then apply it. If the paint goes on fine, dries properly, and has a smooth and glossy finish, then the paint is still good and can be reused.
However, if the paint is difficult to mix, doesn’t dry properly, and gives a rough or discolored finish, then the paint has gone bad.
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How Long Do Oil Paints Last?
Oil paints last between 15 years and 40 years. On average, oil paint would last about 25 years before it begins to go bad.
There is no specific time frame for how long oil paint lasts. How long oil paint would last depends on the storage conditions of the paint and if the paint has been previously opened.
Unopened oil paints tend to last longer than leftover or opened oil paints.
Oil paints have one of the longest shelf life. Oil-based paint can last up to 40 years and remain in good condition. This is very impressive, especially when compared to other paint types. Water-based paints for instance lasts less than 10 years and many acrylic paints don’t even last that long.
However, for oil paint to last that long, the proper storage conditions for the paint have to be kept. Oil paints should be kept at the right room temperature (between 60 degrees Fahrenheit and 80 degrees Fahrenheit), humidity, and in a dry room.
When the right storage conditions are kept, the oil paint can last decades and can be reused anytime. All you just need to do is to revive the paint before using it. So how do you revive old oil paint? Let’s find out.
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How Do You Revive Old Oil Paint?
To revive old oil paint, you need to make the paint softer and reusable. This involves mixing the old oil paint with paint thinner and stirring it with a paint mixer till it has uniform color and consistency.
Let’s check out how to do this in detail but first, here are a few tools you will need to revive old oil paint.
- A Pair Of Work Gloves
- A Face Mask
- A Paint Thinner For Oil Paints. Turpentine is a great choice
- A Large Plastic Container
- A Paint Mixer
Now let’s get to work
Put On Your Safety Gear
When reviving old oil paint, you will be working with chemicals including a paint thinner (turpentine) which for the record isn’t safe to handle with bare hands. So put on a pair of thick gloves and breathing protection.
Pour Out The Oil Paint
The next step is to pour the old oil paint out of its can into a large bowl or plastic container. Be careful when doing this to avoid splashes.
Add Turpentine Or Oil-Based Paint Thinner To The Oil Paint
The next step is to add a paint thinner into the container where you poured the old oil paint. Turpentine is a great choice but if you can’t get your hands on one, ensure to use a paint thinner designed for oil-based paints.
You shouldn’t add too much paint thinner if not you will ruin the thickness of the oil paint.
Stir The Paint And The Paint Thinner
The next step is to stir the paint and thinner with a paint mixer. You can also do this manually but if the oil paint is hard, a paint mixer will work better.
After adding a bit of turpentine, stir the paint for a few minutes. If the paint still feels like it’s hard, you can add more turpentine to the paint and stir again. Paint thinners are active chemicals that soften paint so again, be gentle.
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Test The Paint
After stirring for a few minutes, test the paint by applying it with a paintbrush. If the paint goes on smooth and fine, then you have successfully revived the old oil paint.
If the paint still has a few lumps, you can add a bit more turpentine and stir for a few minutes till you notice even consistency and uniform color.
Overall, oil paints do expire but the paint can last very long before it expires especially if it is stored correctly.
So if you have leftover oil paint, seal it tightly and keep it in a cool and dry room. Whenever you want to use the paint again, revive it with paint thinner and you are good to go.