Why Do You Have to Shake Spray Paint?


How to Paint Over Spray Paint

Most homes around the world have a can of spray paint lying around because of how useful it is for different types of projects. But when you read a can of spray paint’s instructions, it will almost always tell you to shake the can before using the spray paint. So, why do you have to shake spray paint in the first place?

You should shake spray paint because the paint inside the can will most likely settle at the bottom and won’t be as dispersed inside. That means that using the spray paint without shaking it will only release pressurized gas that doesn’t contain a lot of paint pigments because the paint was not mixed well inside.

One might think that using a can of spray paint is quite easy. To some extent, it actually is but you have to consider the fact that you really need to follow the instructions down to the letter if you want to make sure that you are doing things right. That’s why we are here to talk more about why you need to shake a can of spray paint.

Why do you have to shake spray paint?

Using spray paint might look quite easy but there are plenty of people who may not be aware that you have to read the instructions and follow them down to the letter when it comes to using spray paint. And one of the most common mistakes that people make when using spray paint is not shaking the can itself even though the instructions will always tell you to shake it.

But why do people make the mistake of not shaking the can of spray paint? Well, there may be a few reasons:

  1. The first is that some people might not have read the instructions and are inexperienced enough to think that pointing and shooting is the way to go when using spray paint.
  2. Meanwhile, the second reason is that some people just don’t understand the purpose of shaking the can and would rather not do it.

How spray paint works?

For you to understand why it is necessary to shake a can of spray paint, you have to look at the simple mechanics of this nice household tool.

  • Spray paints are actually aerosol cans that are similar to the disinfectant sprays and deodorant sprays you have at home.
  • A can of spray paint works by placing thinned paint inside the can together with pressurized gas (usually carbon dioxide).
  • The pressurized gas, when released and mixed together with the paint pigments inside the can, will spray the paint onto a surface the moment you press the button.
  • The two components (the pressurized gas and the paint) must be mixed well together inside the can so that the gas carries the paint whenever you are releasing it by pressing on the button of the spray.

Paint tends to settle at the bottom

The problem here is that, when the spray paint is left untouched and unused after you had just bought it from the store, the paint tends to settle at the bottom and hasn’t mixed in well inside the can. That means that the paint has “slept” and has not mixed in well with the pressurized gas that the can is housing.

So, when you try to use the spray paint without first shaking the can to mix the paint inside the can, you will only be releasing the pressurized gas that was settling at the top portion of the can. The propellant or the gas that propels that paint will not carry a lot of paint pigments because of this.

As such, you might end up wasting and using up the propellant even though the can still has plenty of paint inside of it. You have to be efficient with the use of your spray paint and make sure that every particle of gas used carries with it paint.

That said, there is a need to thoroughly mix the paint inside the can of spray paint so that it will blend together with the gas. Doing so will make sure that you will not end up wasting the propellant with every use of the spray paint.

How long should you shake spray paint?

The instructions in most brands of spray paint will tell you to shake the can for a minute or two but, to be sure, we recommend that you shake it for about three minutes at first before you are ready to use it. That way, you don’t have to worry about under-mixing the paint inside the can. This applies when you are using the spray paint for the first time.

After your first use of the spray paint, there will be instances where you won’t be using the spray paint for short intervals. When that happens you need to shake the can again because the paint has settled at the bottom. But, this time, you might only need to shake it for about five seconds instead of taking three minutes to do so because you have to make sure the paint inside the can is properly mixed once again.

We have a whole article about how long should you shake spray paint so you can check it out.

Can you over shake spray paint?

When it comes to shaking your can of spray paint, you can never overdo it. That’s because shaking the can will only make sure that the paint inside it is properly mixed so that the propellant will be able to efficiently spray the paint whenever you release the gas. As such, you can take as long as you want when shaking the can of spray paint. But maybe shaking for more than three minutes might end up becoming a waste of time on your part.

Under-shaking the spray paint, however, is a different story. Regardless of whether you are using the spray paint for the first time or for a fifth time, you always need to make sure you never under-shake it. Take as long as you want when shaking the can so that you can be sure that the paint is mixed well inside.

How often do you need to shake spray paint?

There are moments where we may have to stop using the spray paint for a while especially when we have things to do in between. The intervals may be as short as a few seconds or may be as long as a day or two. But, the fact is that there will be times wherein you don’t get to use up all the paint inside the can in one sitting and you will naturally have to let the can of spray paint sit out for a while.

So, when that happens, do you need to shake the spray paint again? Yes, you need to shake the can as often as you can especially when you paused after every use. That’s because the paint inside the can will steadily settle at the bottom even though you are still using the spray paint.

That said, if you want to make sure that the paint doesn’t settle at the bottom and is mixed properly inside the can, you have to shake the spray paint as often as possible.

Best way to spray paint

If you want to make the most out of your spray paint and use it like a pro, here are the tips you might need to know if you are looking for the best way to spray paint:

  • Cover up or use a respirator. Spray paint contains a lot of toxic fumes that can be quite harmful to your body if you inhale it directly. That’s why you need to cover your nose and mouth up by making use of a face mask or even a respirator.
  • Covering your eyes with goggles will also help protect them from the fumes.
  • Work in a well-ventilated area because you want to make sure that any of the toxic fumes coming from the spray paint gets dispersed.
  • It is best to work outdoors and not indoors but make sure to stay away from direct sunlight.
  • Keep a distance of about 10 to 12 inches away from the surface you are spraying on to get the most out of your spray paint. That way, you get to spread the paint across the surface well enough.
  • When spray painting a wide surface, use your entire arm instead of just moving your wrist. Do so in a fluid sweeping motion as your finger is pressed firmly on the spray paint button.
  • If you want to paint a larger surface, try to overlap your presses a bit because you want to give the surface several layers of light coats instead of just one heavy coat for the paint to look better.
  • Allow the paint to dry up a bit before overlapping to ensure that there are multiple coats instead of one heavy coat.
  • Finally, after you are done using the spray paint, turn the can upside-down and then give the button a light press until you see the spray becoming clear.

Dean Luoma

As a long-time homeowner, Dean has been working on his own home projects for over 30 years. He is a licensed real estate agent in the state of Minnesota, helping clients with the buying and selling of their homes.

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