What Rattles Inside Of A Can Of Spray Paint

by George Mylne // Last edited October 2, 2022
what makes the rattle sound inside a can of spray paint

To help mix the paint in a can, there is a “pea” inside of most paint spray cans. The pea can be made of metal, glass or plastic. When the spray paint can is shaken, the pea bounces (or rattles) around the inside of the can mixing up the paint mixture and making the rattle sound.

When a can of spray paint isn’t used for a while, the paint mixture inside of the can starts to separate and settle in the bottom of the can. Shaking the pea inside of the spray can enhances the mixing process, and helps agitate the paint mixture inside of the can.

What is inside of a spray can that rattles
The pea inside of a spray can is what makes the rattle sound.

Why Do Paint Spray Cans Rattle

Spray paint cans rattle because of the pea that is inside of them. The peas purpose is to agitate the paint mixture when the can is shaken.

Peas can be made of either glass, metal or plastic, and the rattle sound is the pea bouncing off the inside walls of the spray paint can.

What Is The Function Of The Rattling Noise A Spray Can Makes

When you shake a can of spray paint, the pea moving and hitting the inside of the can makes the rattle sound. The pea being shaken around acts as an agitator and mixes the paint before use.

The paint particles inside of a spray can are suspended in a fluid, and when a can is left still for some time all of the paint particles will settle on the bottom of the can. Shaking the spray paint can mixes up the paint before use, so when sprayed you will get good quality and cover of paint.

Can You Stop A Paint Spray Can From Rattling

You can stop a paint can from rattling only if the pea is made of metal. If it is made of metal you can hold a strong magnet to the paint can.

The pea will be held against the magnet, and you can move around without making any noise.

How Do You Shake A Spray Paint Can

To shake a can of spray paint, you simply do the following:

  1. Hold can in one hand, and
  2. Shake can up and down (checking that you hear the pea rattling around).

What Should I Do If The Ball Inside Of My Paint Can Doesn’t Rattle?

If you can’t hear the ball inside of the spray can rattle, you will need to hit the can with sufficient force to loosen the pea.

Ways to safely loosen the pea inside of a spray paint can are:

  • Shake the can up and down in your hands very vigorously, or
  • Hit the can against an object that is firm but not to hard. Hitting the can against a car tyre, dirt or grass may help dislodge the pea.

About the author George Mylne

George has been a surveyor for over 13 years, working across a wide range of projects and industries. In this blog, he shares his experiences and information gathered from his time on mining, civil and surveying projects.

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