I doubt that I’m the only who has at least a gallon of paint stored in the garage dating as far back as ‘god knows when’. These not-so-ancient artifacts can often be found in corners or cabinets where they have been placed “for future use”. You can store paint for a long time and use it again when the need for it arises, but you have to store it properly.
Unopened cans of paint (not aeorosol) can last for 10-15 years if they are stored at room temperature. Water-based acrylics and latex last up to 10 years if the can is sealed and stored at room temperature while oil-based paints last closer to 15 years under the same circumstances.
In a sealed aerosol can, spray paints can last almost indefinitely if stored correctly. Spray paint cans may work just fine even after 20 years in proper conditions. Some issues may arise when storing spray paint, such as; the nozzle clogging up, the can may lose its pressure, and the paint can harden. When storing paint, keep it above 41 and under 95 degrees Fahrenheit at all times. Shake the can for a minute a couple of times a year.
When it comes to open cans of paint it’s quite hard to give even a rough estimate regarding the paint’s lifespan without looking at the actual paint. By looking at the paint, smelling it and trying it on a bit of cardboard, you can actually tell if it’s suitable for use or if it’s ruined.
We’ll talk about signs of dead paint, how to maintain paint for a long time, and how to fix paint and spray cans.
How Long Does Spray Paint Really Last?
Cans of spray paint can last forever if stored and maintained properly.
Even opened cans last for a long time. I’ve stored cans of paint for years and most have worked just fine. The most common trouble you will run across when using old, stored paint is failure to shake the can thoroughly before spraying it for the first time in years.
During all that time in storage, the paint and the solvents have most likely separated, causing the paint to thicken. The thickened paint will lay like sediment at the bottom of the spray can, waiting to be pressed through the dip tube up through the nozzle and out into the air. However, the tube will not be able to push the sediment-like paint and it will definitely not be able to spray it, causing it to clog up the nozzle.
You may seem tempted to pick up an old can to give it a “test shot” but you will most likely cause pluggage the second you press the valve, causing much more trouble than you initially had. Instead, shake the bottle like a madman for a good minute or two before testing if it still sprays. That way, the sediment collected at the bottom will have mixed with the solvent, regained it’s viscosity, and should now be able to travel through the dip tube nicely.
By simply shaking a can of spray paint you will be able to restore it the majority of the time. There are exceptions but many spray paint cans will be brought back to life. However, it would be much better if you could avoid this problem all together, ensuring that every can of paint stored in your garage is in good condition, and you can – it’s simple.
Every now and then, say 2-3 times a year, I make sure to the shake every single can of paint for at least a minute to make sure that it isn’t ruined or lumpy when it’s time to use it again. Depending on the size of your collection, it could be wise to take the opportunity to reach out to family members for some shake-asisstance.
With my collection of paint, it’s been well worth “employing” my kids when it’s time to shake. I always make sure we do it together and I teach them the importance of safety when handling paint and other strong chemicals.
By doing this simple thing you can make sure your spray paint will last for a long time, multiple years, without any issues at all. Generally, unsealed cans will be more problematic than sealed ones but so far, I’ve had success with both.
If simply shaking the can isn’t enough, there’s more you can do to restore your old cans of spray paint. Covering the most common issue is important, but now let’s take a look at the rest of the problems that may be rendering your old can useless.
Why Do Spray Paint Cans Stop Working?
Spray paint doesn’t really expire per se, like food. There may be a best-before date on it but it’s hard to pin point when in time a can of spray paint will ruin, as it depends so much on how the paint is maintained and cared for. There are conditions which, if exposed to it, will ruin a can of paint in much less time than the average lifespan.
Quite often, it’s the can that stops working rather than the paint. The paint may be usable while the can is unable to spray it, as a result of clogging or loss of pressure.
The Can’s Nozzle Has Clogged Up
Some cans will still clog up even though they have been thrown around intensively for a minute or two. The sediment may still have made its way into the dip tube or nozzle and either dried there or just created a blockade, preventing the can from spraying when the button on the valve is pushed.
Rustoleum aerosol cans tend to be challenging because of the above average concetration of solids, and will oftentimes require more than just shaking the can in order to open it up.
You can either clean the nozzle by using compressed air, which will remove much of the dried paint that’s stuck inside the tube or soak the can in a bath of warm water. The warm water makes the paint thinner and causes it to atomize faster – allowing the can to spray it once again.
Tip: When you’ve finished a can of spray paint, remove the nozzle and store it as a replacement nozzle in case another one clogs up.
The Can Has Lost Its Pressure
Over time, most of your household cans will depressurize, be it shaving gel, cooking spray or paint spray cans. It’s quite frustrating to give up on a can that’s half full of perfectly fine product simply because the can doesn’t cooperate. It’s a process that doesn’t happen overnight but it can happen relatively quickly once the can has been opened.
To my understanding, the propellant (gas) inside the can acts as a force that pushes the product out of the nozzle when the delivery tip is pushed down. There’s a valve under the delivery tip that’s designed to keep the product and the propellants from escaping the can when the button isn’t pushed down.
The gas helps the valve stay closed but the more the can is used, the more the gas escapes as it forces the product out of the can – leaving less and less gas inside the can to seal the valve. Ultimately, this may cause a used can to start leaking, allowing the pressurized gas to escape the can, making it very difficult to get any paint out of it.
Bringing the non-working cans back to the retailer to get them pressurized would be an option, but more often than not, the cans will have depressurized well beyond most store’s return policies.
I don’t recommend pressurizing the cans at home, by yourself. Most spray cans aren’t filled with just air, as it would have dried out the product before it’s even sprayed. Instead, they’re pressurized using propellants. The process often involves butane and propane, which are flammable gasses and unless you’re familiar with them and have the proper equipment, I wouldn’t think about doing it.
With that in mind, I try my absolute best to purchase only the amount of spray paint needed to finish a project, I want as few half-full paint cans as possible whenever I’m done painting, but to be frank, I rarely get it right. This can be verified by the collection of used cans residing in our home.
Can You Get Paint Out of a Spray Paint Can?
If you think I just dispose of them because they’ve stopped working, you’re not completely right. Depending on the amount of paint left in the can, I may try to get the paint out of the can, in an effort to prevent my hobbies from ruining me financially. The withdrawn paint can then be used with an airbrush or a spray paint gun.
To get the paint out of the can, carefully penetrate the top of the can with a sharp object to let excess pressure vent out before pouring the paint into a sealable container.
It’s called decanting paint and it’s a sraight forward method that requires little experience. If you are harboring doubts and feel insecure about opening up a can of paint, I recommend watching this guide on YouTube first.
How To Store Cans of Spray Paint
In order to make spray paint cans last as long as possible, it’s important to store them in optimal conditions. Failing to do so may ruin the cans, rendering them useless the next time you need them. With that said, here are a few guidelines that, hopefully, will extend the lifetime of stored spray paint cans.
- Put the lid back on the can to keep the paint fresh and preventing the can from accidentally triggering, which could happen if its forced into a tight space.
- Spray paint must be stored at the right temperature, neglecting that fact may cause your paint to ruin or your can to burst. The perfect temperature seems to be somewhere between 41 and 95 degrees Fahrenheit.
- Never store paint in a spot where it may have direct contact with sunlight.
- Don’t make it easily available for kids or pets.
- Keep it in a dry spot and away from flames and sparks, as they may cause the can to burst.
Does Spray Paint Expire?
Unless the paint inside the can cures through a chemical reaction of sorts, it won’t go bad. It’s rarely the paint that’s unusable but rather the can that’s lost its function because of loss of pressure over time. Sealed spray paint cans that are stored in the right temperatures won’t really go bad and can many times be used several years after purchase.
How To Tell If Spray Paint is Bad
It’s not as much “the paint going bad” as it is “the paint might need maintenance prior to use”. Paints that have been standing idle for a long time may simply need a shake in order to mix the solvents properly.
You could also come across a scenario where your paint spray isn’t spraying through the nozzle. Instead, the paint has changed into a thick dripping liquid falling out of the nozzle. Always spray a piece of cardboard before spraying the object you intend to paint to see if there’s bubbles or lumps in your paint. If so, you may have to shake the bottle, place it in warm water to raise the internal pressure, or decant it.