How To Make Your Acrylic Paint Smooth on Plastic    

Painting on plastic is a great way to label your belongings, decorate old items, or breathe new life into those that have already started looking shabby. Painting on plastic can be tricky, though, since it is non-porous, smooth, and shiny. Acrylic paint tends to slide off quickly because it doesn’t have a good surface to adhere to and has a similar consistency as plastic when it dries.

You can make acrylic paint smooth on plastic by sanding the plastic surface you’re going to paint on and applying primer before starting. Sand the surface to create a rougher layer to which the paint can stick. Then, apply even layers of primer for maximum adherence.

In this article, I will talk about the strategies you must employ to prepare any plastic surface for painting. I will also offer tips on how best to apply primer, acrylic paint, and sealant on your plastic items to make them look better and last longer. So, How To Make Your Acrylic Paint Smooth on Plastic? Let’s start!

6 Steps To Make Your Acrylic Paint Smooth on Plastic

Clean the Plastic Surface

Clean the surface of your plastic item thoroughly. Dish soap, warm water, and a dishwashing sponge will do. Make sure you get rid of all dirt, stains, and other unwanted materials that may have gotten stuck on the surface since these may, later on, give the finished product an uneven look. 

Sand the Plastic Surface

Grab a piece of 180 to 220-grit sandpaper and get to work roughening up the surface. If you’re working on a particularly large piece of plastic, consider using a random orbital sander instead.  However, make sure to sand lightly since you might end up melting the plastic. If you’re not adept at using an orbital sander, opt for doing it by hand. 

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Sanding is necessary to create a more ideal surface for the acrylic paint to bond thoroughly. This helps get rid of the shiny, non-porous surface so that your paint has increased chances of adhering. Sanding can also eliminate any films or grease that washing with soap couldn’t get rid of. 

Wipe Off the Debris

When you’re done sanding the plastic surface, grab a piece of damp cloth and wipe away all the dust. Next, cover the entire surface with rubbing alcohol and gently wipe away with a clean piece of cloth. This removes any leftover debris, grease, or oil on the surface. Leave the plastic item to dry in a well-ventilated area. 

Apply the Primer

Choose a primer that is formulated to work well with plastics. A coating or 2 of primer will help paint stick better to the plastic surface. When it comes to acrylic paint, at least 2 layers of primer are advisable to help the paint adhere more strongly to the surface. 

This is how to do it:

1. Use masking tape or painter’s tape to block off areas you don’t plan on painting. This strategy is good if you’re looking into painting small details later on or if you want certain effects on the finished product. Make sure that the tape is completely flat, so no primer or paint seeps in.
2. Apply a thin, even coat of primer on the entire surface using a brush. Leave the plastic item in a well-ventilated space to allow the primer to dry completely. 
3. Apply the second coat of primer. Wait for this to thoroughly dry as well. 

If unsure whether your primer is compatible with your acrylic paint, you can do a simple test. This is how to do it:

1. Select a small plastic item made of a similar material to the plastic item you’ll be painting on. 
2. Apply the primer, then wait for it to completely dry. 
3. Apply another coat of primer and wait for this layer to dry.
4. Apply acrylic paint and wait for it to completely dry. 
5. Scratch the surface of the plastic item with a kitchen knife.
6. Cover the scratch mark with a piece of masking tape and smooth it down thoroughly. 
7. Rip the masking tape off. 

If paint comes off with the tape, your primer and acrylic paint are incompatible. If no paint comes off, you can go ahead with your project because this means that your primer and acrylic paint work well together. 

Primers in Spray Cans

Some primers come in spray cans, which can help make the job a lot easier for you. However, there are a couple of precautions you need to take notice of since working with any type of sprayable substance can be harmful to your health.

Here are some tips in case you decide to go for a sprayable primer:

• Ideally, it is better to work outdoors because there is excellent air circulation. If working outdoors is not possible, make sure the area you’ll be working in indoors has good ventilation. Opening doors and windows would significantly help.
• Wear protective gear. Arm yourself with a face mask, goggles, and gloves. 
• Spray primer from about 20 inches (50 cm) away. Make sure to spray lightly and evenly across the entire surface. Use masking tape or painter’s tape to block off areas you don’t want any paint on.

Apply Acrylic Paint

Applying acrylic paint on your plastic item is pretty much similar to applying primer.  Apply a layer of paint and wait for it to dry before adding the next coat. However, if you’re already satisfied with the shade from the first layer, adding a second one isn’t necessary. 

Also, make sure that you’re painting in an area with good ventilation. Outdoors is best, but if this isn’t feasible, throw open the windows and doors to allow air to freely go in and out of the area. It would be wise to keep children and pets away since the fumes from the paint may be harmful to them. To protect yourself, wear your protective gear: gloves, face mask, and goggles. 

Whether you’re applying paint using a brush or spray can, there are some crucial factors you must remember so that your work is neat and the paint job lasts longer. Here are some tips:

• Apply even, thin coats of paint. Avoid layering on thick coatings since your paint job might be prone to peeling.
• If you’re applying a second coat, allow the first layer to completely dry up. Each coat takes about 15-20 minutes to dry.
• Make sure that each coat is even in thickness. This helps prevent flaking and peeling. 
• Remove the masking tape or painter’s paint at once. Make sure to do this before your paint dries since you might end up peeling off some of the fresh paint as well. 
• Allow the finished product to dry in a well-ventilated area. This usually takes at least 12 hours. Some people let their plastic items dry for 24 hours to ensure the paint is completely dry. 

Seal the Acrylic Paint on the Plastic

Applying a sealant over the acrylic paint will help make your work last longer. It will also help prevent scratches, bumps, and peeling. Furthermore, a suitable sealant can add a waterproof layer to the plastic item to protect it from the damaging effects of moisture or rain. 

Here is how to apply a sealant over acrylic paint on plastic (this applies to both brush and spray application):

1. Apply a thin, even coat of sealant on the entire surface. Allow the sealant to dry in a well-ventilated space. 
2. Apply a second coat of sealant, ensuring that this layer is of the same thickness as the first. Wait for this layer to thoroughly dry as well. 
3. Apply an extra layer of sealant if the item is intended for outdoor use. This will provide added protection from the elements. 
4. Wait for the final layer of sealant to completely dry. It would be best to leave the plastic item in a well-ventilated area for at least 24 hours.

Final Words

Using acrylic paint to paint on plastic doesn’t have to be tricky. All you need to do is sand the surface and apply primer before painting. By following these tips, you’ll be able to paint smoothly on plastic!