Can You Spray Paint Styrofoam [Step-By-Step Guide With Precautions]

Spray painting is not just a fun activity, it’s also one of the most effective ones. It allows you to reach all the nooks and crannies you could never hope to reach with regular brushes. And it allows you to paint those nooks and crannies in record time.

But can you spray paint styrofoam as well?

Yes, you can use spray paint to paint over styrofoam as long as it doesn’t carry any oil-based solvents or thinners. Enamel or similar chemicals help to corrode sensitive materials like styrofoam and its derivatives. To spray paint styrofoam, you will need to use water-based latex/acrylic spray paint instead.

While there are limitations, it’s not impossible to use styrofoam as a canvas for your spray painting cravings. Today, let’s figure out the proactive solutions to these limitations so that you can safely and efficiently spray paint styrofoam around the house.

Does Spray Paint Melt Styrofoam?

Under certain circumstances, spray paint can melt the styrofoam. Here’s a brief overview of some of the prominent chemicals found in normal spray paint & their effects on styrofoam –

ComponentEffects On Styrofoam
AcetoneDegrades the fragile polymer makes the foam shrink makes the surface flammableReacts hazardously with the hydrocarbon-based styrofoamDissolves the upper surface with extensive application
EpoxyReacts with VOCs in the styrofoamTraps heat within the polystyrene moleculesHelps the styrofoam to melt faster in contact with heatWorks like a catalyst to melt the styrofoam with the help of exothermic reactions
BenzeneResponsible for reacting with the polymer and causing a bad odorMelts the styrofoam with time
TolueneBlackens the surface significantly after melting the styrofoamCreates toxic hydrocarbon fumesCreates new solid hydrocarbon layers after melting and ruins the smoothness of the surface.
Oil-Based SolventsReacts with VOCs in the styrofoamTraps heat within the polystyrene moleculesHelps the styrofoam to melt faster in contact with networks like a catalyst to melt the styrofoam with the help of exothermic reactions
TCE (1,1,1- TriChloroEthane)Separates the color pigments after molecular reactions between the componentsDissolves the styrofoam directly if there’s a high concentration of toluene alongside TCE

Once the surface layer is compromised, it doesn’t take much for the corrosive chemical agents in certain spray paints to destroy the integrity of the rest of the styrofoam. Hence, it’s important to read the labels on the spray paint cans before buying them impulsively.

Read more – How Old To Buy Spray Paint?

Spray Painting Styrofoam: Step-By-Step Guide

Once you’ve got the correct non-corrosive water-based spray paint, you don’t have to worry about melting the styrofoam. Here’s a step-by-step guide on how to spray paint styrofoam effectively with minimal repercussions –

Step 1: Prepare The Materials

Check out the following list of materials you should keep nearby to thoroughly spray paint some styrofoam –

  • Styrofoam
  • Spray paint cans
  • Gloves
  • Face Masks
  • Painting mats
  • Mask tapes
  • Fans, etc.

Once you’ve got all of these materials, select the painting area. Make sure the area is secluded and well-ventilated. Place down the painting mats so that the paint doesn’t ruin the floor. Wear gloves and face masks to avoid spray paint fumes.

Step 2: Apply The First Coat

For free-hand application, apply the first coat however you see fit. Just make sure to hold the can at least 7-8 inches from the styrofoam so that the paint can dissipate properly. Again, if you want strict lines, place light masking tapes around the edges first & apply the first paint coating.

To ensure an even amount of paint everywhere, always stay in motion while spray painting. Follow a linear pattern to cover the entire area thoroughly. Don’t spray without pause. Instead, paint with short intervals to avoid sudden streaks.

Step 3: Apply The Second Coat

Since the first coat is not too dense, it shouldn’t take more than 20-25 minutes to dry up. Follow step 2 to apply the second coat in the same manner. It’s important to remember and follow the same linear pattern while spray painting.

Otherwise, you’ll risk painting over the same area multiple times. Alternatively, you’ll end up creating a puddle of paint in the nearby regions while trying to fill up the empty spaces.

Step 4: Allow The Paint To Dry Naturally

You can go for multiple coatings to cover the area properly. However, make sure to let the previous coating dry up completely before applying the next one. And avoid applying too many layers, as they can lead to paint clumping.

After the final application, leave the styrofoam under a ceiling fan for proper air circulation. Don’t dry styrofoam under the sun or with the use of any kind of heat.

Step 5: Final Touches

After the paint dries up, get rid of the masking tape. Use brushes to touch up the lines personally for better texture. People mostly use spray paint on styrofoam to establish a background for further creative arrangements.

If that is the case, take out your painting kit and finish the rest of the painting before you can seal the surface up.

How To Make Spray Paint Stick To Styrofoam?

Let’s face it. You can’t hope for a glossy finish on styrofoam cups, boards, toys, etc., with spray paint. Since the surface is incredibly porous, spray paint can’t adhere to it all that well. So, you have to seal the surface to both beautify and increase the longevity of the raw application.

With water-based spray paint, use lacquer varnish to seal the paint on the styrofoam. In addition to securing the paint layers, the varnish also prevents premature discoloration, and styrofoam degradation due to sunlight, dust, chemicals, etc.

How Not To Melt Styrofoam With Spray Paint: Precautionary Measures

Spray painting styrofoam might sound like a fun project, but styrofoam fumes can produce some of the most toxic chemicals on earth. As such, it’s important to ensure proper precautions to avoid melting styrofoam at all costs –

Always Test Before The Application

Not all styrofoam can take spray paint, and not all spray paint can accommodate styrofoam. Depending on the materials used, the results can vary every time. Hence, it’s important to conduct a test phase before mass application.

Before spray painting styrofoam, cut out a piece or use a scrap piece to see how the paint reacts with the foam. While spray painting, if you hear any sizzling noise or if the foam starts to go black, it means the spray paint is toxic.

Toxic in the sense that it’s toxic for that specific foam. It either contains turpentine or similar oil-based agents, and most spray paint will melt if these chemicals are involved.

Always Use Clean Styrofoam

Don’t spray paint on dusty styrofoam and waste both your time and money. If the surface is dusty, the spray paint molecules won’t adhere to the surface at all. And after the painting sessions, you’ll be left with empty colorless splotches throughout the styrofoam.

So, before spray painting styrofoam, clean the surface with a wet sponge to get rid of the dust. Refrain from scrubbing so that you don’t end up loosening the styrofoam particles.

Alternatively, you can scrub the upper surface with sandpaper to get rid of the dirty layer completely. Keep the styrofoam board on a solid table/floor, etc., and sand the top to bring out the fresh styrofoam underneath the dirty one.

Buy Spray Paint Cans With More Coverage

While buying spray paint cans for styrofoam, you have to check the label for three things. And they’re – whether the solvent is oil-based or water-based, whether they’re safe for painting fragile items like styrofoam, and their coverage.

Because with styrofoam, you need to apply at least 2-3 coats for the color to pop properly. With low coverage, it’ll not only take longer to paint the board, but it’ll also take more paint. Hence, we’d recommend checking out the coverage rate before ordering the spray paint cans.

If the coverage rate is similar to that of oil-based spray paint, look for other options since water-based spray paint already offers more coverage than oil-based spray paint.

Read more – Can You Use Acrylic Paint On Walls?

Frequently Asked Questions

Q: Can you use masking tape on styrofoam?

Yes, if you’re looking to maintain proper lines, then it’s a good idea to use masking tape on styrofoam. However, make sure the surface is properly sealed before putting on the tape. And don’t take the tape off before the paint has dried completely. Otherwise, the paint might seep into the crevices and ruin the straight lines.

Q: How long does it take for spray paint to dry on styrofoam?

With proper airflow, it shouldn’t take more than an hour or two for spray paint to dry on styrofoam. However, it’s best to avoid direct airflow during the painting procedure itself. Since the spray paint particles are quite light, direct airflow will hamper the application process.

Q: Can you use acrylic paint on styrofoam?

Yes, most acrylic paint can be safely used on styrofoam. Because quality acrylic paint is not only water-based but also water-resistant once they dry properly. So, not only does it let the foam breathe, it protects the surface from further damage.

Q: Can you reuse the melted styrofoam?

With minimal deformation, you can cut off the deformed area and reuse the rest of the styrofoam. And with major structure degradation, wear gloves to alter the shape personally. Consequently, if the damage is severe, it’s best to cut your losses and throw away the melted styrofoam to recycle.

Q: Can you use a hair dryer on spray-painted styrofoam?

No, a hair dryer will heat up the air and consequently melt the styrofoam instead of drying it. It’s best to let styrofoam dry naturally in the open air or use a fan for a cold flow of air.

Before You Go

While you can spray paint styrofoam, make sure to arrange for proper ventilation during the procedure. And don’t forget to use intact styrofoam since it’s easier to seal the intact ones.

If you’re looking to use the leftover paint on other objects around the house, check out – Can You Spray Paint Shoes?

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