Acrylic paint is easily the most versatile paint in the world. It’s a simple water-based pigment that can be found in most stores for an affordable price. Artists have used acrylic to paint everything from canvas and fabric to pottery and ceramics.
One question that I’ve gotten a lot recently, though, is, “Does acrylic paint work on plastic?”
By itself, acrylic paint will not work on plastic. This is because both plastic and acrylic paint have similar surface tension, which limits how well acrylic paint can adhere to plastic. In most cases, the result is that the acrylic paint will peel off of the plastic when it’s dry.
By priming the plastic’s surface, though, you can solve this problem!
Plastic has become an increasingly popular material for artists to paint on. As long as you take the necessary steps to prepare the surface for painting, then you’ll be able to create unique pieces of art, paint your furniture, and more using acrylic paint. In today’s post, I’m going to show you all of the steps you need to take in order to prepare your plastic surface so that you can paint it!
Why Can’t Acrylic Bond Directly To Plastic?
When most people ask me whether or not acrylic paint can bind to plastic, I just give them the simple answer- no. Most people find it somewhat odd because acrylic paint usually works on just about any surface, even glass (as noted by my previous article).
The reason why acrylic can’t bind directly to plastic surfaces is rather scientific, but I’ll do my best to break it down in simple terms. The problem is that both acrylic paint and hard plastic have similar surface tension. When two materials have similar surface tension, they don’t bond well together.
Here’s a quick example to help you understand why. Let’s just say you bounce a tennis ball against the hard floor. It should bounce right back up. Now, let’s just say that there’s a bunch of velcro on the ground, and you throw the tennis ball down at the sticky velcro.
In scenario one, both the ball and the ground have similar surface tension, and no bond is created. In the second scenario, the velcro has higher surface tension than the tennis ball, causing the two surfaces to bond. Obviously, this is a rudimentary explanation, but hopefully, you get the picture.
Keep in mind that acrylic paint is also created using plastic molecules. This is what makes it such a versatile and durable paint. However, it also means that you’ll have problems if you just try to apply it straight to plastic without preparing the area first.
How To Use Acrylic Paint On Plastic
So, now that you understand the science behind why acrylic and plastic don’t play well together, it’s time to present you with the solution. Thankfully, it’s fairly simple. As long as you prepare the surface of the plastic and increase its surface tension, then you can get the acrylic paint to bind to it! This is accomplished by sanding and applying a primer to the surface.
Step 1: Sand The Plastic
Your first step should be to sand the plastic. You don’t need to use any special tools or sand the plastic down with a fine-grit as you would do with wood. In most cases, just using a 120-grit piece of sandpaper or a sanding block will be more than enough to prepare the plastic.
The main goal during this process is to make the surface of the plastic rougher. The rougher the plastic’s surface is, the easier it will be for the primer to stick to the surface. Just take your sandpaper and rapidly move it in lateral and circular motions along all of the surfaces that you plan on painting. When you’re finished, the surface should feel rough to the touch.
Step 2: Clean The Plastic
Before doing anything else, your second step should be to thoroughly clean the plastic. I recommend wiping everything down using a cloth and some mineral spirits. This will accomplish two things:
- It will clean away any plastic shavings that were created during the sanding process.
- It will clean any residual dirt, oil, or other grime on the plastic’s surface.
Making sure the plastic is clean is important because any dirt that gets stuck under the primer can cause the paint to peel or bubble prematurely, thus ruining your project.
Step 3: Prime The Plastic With A Thick Coat
Once the plastic is sanded, cleaned, and 100% dry, it’s time for the fun part- priming. For this part, I recommend using an all-purpose spray paint primer. You can usually find a can of this at your local hardware store for a few bucks. It’s usually a neutral gray color.
Before spraying, you’ll want to vigorously shake the can for 60 to 120 seconds. This will mix up the contents and ensure that they spray evenly. Next, spray a light coat over the entire surface of the plastic. Give it about 5 minutes to dry, and then spray the plastic one more time with another coat to create a thicker layer of primer for the acrylic to stick to. Let the primer [cure] for 1 hour to be safe.
Step 4: Apply Your Acrylic Paint
Now, it’s time to add some color and make your masterpiece! Using a brush, roller, or spray gun, apply your acrylic paint evenly across the primed and dry surface of the plastic. I usually recommend using an enamel-based acrylic paint as it results in a harder, smoother, and more water-resistant finish that suits the natural look of the plastic. It will also help smooth out any unevenness caused by sanding.
Step 5 (Optional): Apply Varnish Or Sealant
Lastly, you may want to apply a sealant to protect the paint from damage. I especially recommend this if you’re painting outdoor furniture, vinyl siding and shutters, or anything else that’s going to be exposed to the elements, sat on, or handled frequently.