The Money Pit
Home Improvement Tips & Podcasts
Storing Paint: Best Way to Make Paint Last
George asks,
After painting I have two partially used cans of latex paint. I know that in storage it will be evaporation of water, benzene, toluene, and formaldehyde which results in paint hardening in 3-5 years. Can the shelf life be improved if all the air in the cans to be stored were replaced with water to displace all the air?
I’ve never heard of your suggestion that filling a can of leftover latex paint with water to take up the air space to preserve it. And, it doesn’t seem it’d work all that well for storing paint anyway as the water will simply mix with the latex (water base paint)! I have a few other suggestions you may find helpful.
When it comes to storing paint and the life expectancy of leftover paint, most manufacturers will tell you that paint can last 2-3 years. My personal experience is that it can last longer. Success depends not only on where the paint is stored, but even more importantly the condition of the can.
The enemy of storing paint is simply – air. The more air that gets into that can, the shorter the life of the paint. So, the seal is key to storing paint for the long run. Here are a few things I have learned that can help.
First, when you open a new can of paint, don’t use a screwdriver. Instead you a paint can opener tool. Prying open the lid this way can bend the edge and make it more difficult to get a seal when the lid is replaced. It’s ok to use the screwdriver to carefully poke drainage holes in the bottom of the channel inside the can, but don’t use it to pry the lid off initially.
When you are done with the paint, use the brush to clean the seam as much as possible on the paint can and use a rag to wipe the opposing seam on the lid. Paint that dries in either area will prevent the lid from sealing completely.
TIP: In addition, paint that sits in the seam are can cause rust which can discolor the paint, a lesson I learned the hard way. Some years ago, I tried to touch up some woodwork in my home using paint from the same can I initially painted the wood with. I noticed that the color was slightly darker. It really bugged me for a while because I could not for the life of me understand why. The solution became appeared the next time I opened the can and noticed that a few flakes of rust had fallen into the paint. That small bit of rust was like a dye that spread throughout the can when I stirred it and resulted in a brand-new shade I was not planning on!
Next, cover the open can with a piece of clear plastic wrap (like Saran Wrap). This acts as a gasket and provides and additional level of seal protection preventing air from getting into the can.
Finally, place the lid on and then tap it down, gently at first, using a rubber mallet (prevents dents and damage to the seam portion of the lid). Once the lid is in place, hit it again more firmly with the rubber mallet to complete the process.
TIP: If you lay a rag over the can before hammering the lid closed, you’ll both protect the lid and catch any paint spray that might launch off the lid and land on you or your work area!
Once this is done, store the paint in a cool, dry area, that is not subject to temperature extremes. If you have a basement, that’s perfect. If not, you can store it in the back of a cabinet or closet on your first floor.
I’ve stored paint this way and had it last 5 years, which is about twice as long as it should have. One last tip: get in the habit of writing the date the paint was first opened on the can. This way you can easily track the paint’s “shelf life”. Who knows, maybe you’ll find out you can store leftover paint a lot longer than anyone thought possible!
I like the idea of the self sealing bag above. You could also use your old plastic grocery bags & seal the the bag tightly with a twist tie or simply twisting the loose end around a few times & knotting it. I’ve used the grocery bags also instead of plastic wrap as mentioned in the article. Put the bag over the can, or even use it “double layer” by laying it across the opening & then tapping the lid back on with the mallet. I’ve then used some large rubber bands to secure the plastic down around the sides of the can. I have paint in my “cellar” that has a bag over it this way & the lid isn’t even that tight because of paint build up on the rim, but even after a couple years or more (I don’t keep track) when lift the lid off & remove the plastic seal, the paint’s still good. If you have a good seal with the plastic I don’t think you even need the lid, but I keep it because it usually has the paint mixing info on it.
AFTER YOU TAP ONE SIDE OF THE LID CLOSED, YOU,’LL STILL HAVE THE OPPOSITE END OPENED A LITTLE. PULL IT UP A LITTLE MORE AND IN ONE BREATH, EXHALE AS MUCH CO2 AS POSSIBLE INTO THE CAN AND SLAM IT SHUT. USE YOUR RUBBER MALLOT TO SECURE THE LID IN A CRISSCROS MOTION. WITH NO BOTTLED NITROGEN ON OUR SHELVES AT HOME, YOU JUST DISPLACED THE AIR WITH ENOUGH CO 2. TO STORE YOUR PAINT FOR 6 YEARS.
GET THOSE CLEAR HD 12 X 16 SHIPPING BAGS WITH THE SELF SEALING TOPS, PLACE AND YOUR GALLON IN IT – UPSIDE DOWN !!!……. NO AIR IS GETTING IN AND THE COLORANTS AND BINDERS WILL SETTLE. WHEN YOU’RE READY FOR ANOTHER PROJECT OR TOUCH UP JUST FLIP IT OVER 2 DAYS PRIOR AND MIXING IS A CINCH BECAUSE EVERYTHING IS BACK IN THE PAINT AND NOT ON THE BOTTOM OF THE CAN.LABLE WITH THE DATE, COLOR AND WHERE IT WAS USED. ALOHA………………….