Will Spray Paint Melt Styrofoam: 5 Ways to Get Rid of Melted Issue

Will Spray Paint Melt Styrofoam

Have you decided to use spray paints on Styrofoam? Do you know it can cause melting issues on the Styrofoam if you use the wrong products? Hence, before choosing a particular spray paint, you must know the answer to this question: Will spray paint melt Styrofoam?

It is good to decorate your particular Styrofoam object. If your specific spray paint damages the surface, all the hard work will go in vain. So, it is crucial to know what things can cause melting or dissolving issues to Styrofoam and how to avoid them.

In this write-up, I will go for an in-depth discussion of why does spray paint melt Styrofoam and what protective actions you can take to avoid such a scenario. So let’s start without further ado!

What Melts Styrofoam?

Different types of materials or products can cause melting issues for Styrofoam. Here 5 of them

a) Turpentine

Many oil-based spray paints can melt and dissolve Styrofoam if the formula contains turpentine solvent. This is because both turpentine and polystyrene (PS) foams have compatible molecular properties.

Turpentine is a liquid substance, while Styrofoam is solid, lightweight substance. Since the holding power of liquid molecules is higher than stable molecules, it puts extra force.

This will ultimately dissolve Styrofoam after a specific time. The time taken for dissolution may vary depending upon Styrofoam’s physical structure and properties.

b) Polyester or Epoxy

Any idea on how to melt Styrofoam? Another common solvent many solvent-based paints include is Polyester or Epoxy. However, this ingredient is not as hard as Turpentine.

Polyester or Epoxy causes melting issues when you apply too thick a layer of paints on the Styrofoam surface. So, how Epoxy melts polystyrene (PS) foams?

Applying extremely thick or too large paints leads to an exotherm process, which increases the overall heat on the painted surface. This will ultimately cause melting issues.

c) Acetone

One of the most common things people use to melt or dissolve Styrofoam is acetone. It works like magic. So, how does acetone melt Styrofoam?

Styrofoam mainly consists of a massive number of strands of styrene molecules, including ample air pockets. Hence, it is known as polystyrene.

The styrene strands play a crucial role in melting Styrofoam easily. When polystyrene and acetone come closes to each other, they react instantly. This causes Styrofoam to dissolve easily.

d) Gasoline

Another common item is gasoline, which can easily melt any polymer hydrocarbon-based Styrofoam. But the result won’t be as intense as acetone.

e) Spray Paint

What about spray paint? Will spray paint eat spray foam? A lot of solvent-based spray paint can cause deadly damage to your Styrofoam.

Many of them are so hazardous that they work instantly to dissolve foam like acetone. So, which solvent-based spray paints cause melting issues for Styrofoam?

Spray paints are made of dozens of ingredients. Before choosing a particular one, you must know whether the ingredient will cause melting issues or not.

Does Styrofoam Dissolve So Easily?

Dissolving Styrofoam is as easy as you dissolve sugar in hot water. Solvents are so powerful that a small quantity is enough to disappear a vast amount of polystyrene (PS) foams.

For instance, a while bean bag of Styrofoam beads can be easily eaten by a cup of acetone. Many people take it as a chemical reaction. But they are wrong since it is a physical reaction.

So, why does Styrofoam melt so effortlessly? The entire physical structure of Styrofoam contains a higher percentage of air. So, when it contacts any powerful solvents, it can’t hold its form.

It’s stringy with lots of visible air holes that will dissolve and ultimately vanish within a short time. So, the natural physical structure of polystyrene (PS) foams causes them to dissolve.

Does Styrofoam Really Melt If You Spray Paint It?

If you have not used spray paints on any Styrofoam, you must wonder, “Does spray paint melts Styrofoam?” Yes, spray paints can melt polystyrene (PS) foams, but not all.

Whether a spray paint will melt Styrofoam or not will depend on the type of solvent the paint has. Hence, choosing the right paint is important.

Here are the most common of them that many manufacturers use in solvent-based spray paints.

  • Acetone
  • Toluene
  • Methyl Ethyl Ketone
  • 1,1,1-trichloroethane
  • Benzene
  • Dimethylformamide

So, the above solvents are the main cause for dissolving Styrofoam. Therefore, try to avoid all of them when you choose spray paint.

Why Does Spray Paint Melt Styrofoam?

what melts styrofoam

Not all spray paints will melt Styrofoam. Spray paint can only melt or dissolve Styrofoam when it affects the physical properties of this polystyrene (PS).

Oil-based, latex or enamel-based spray paints can cause melting issues on Styrofoam. Here are a few factors that will determine whether spray paint will affect the existence of this foam.

a) Chemicals or Solvents

How many chemicals or solvents does your oil-based, latex, or enamel-based spray paint have? For example, Styrofoam may start to melt if your latest spray paint contains a higher number of resins (binder) and limestone (extender).

According to studies, enamel-based paints are most hazardous for Styrofoam — because they contain dimethyl ketone or propanone (acetone), methyl ethyl ketone, etc.

So, when you want to use such type of spray paints, double-check their ingredients. If the paint contains these chemicals or solvents, you must avoid them.

b) Excessive Amount of Paints

Some spray paints may have limited or little solvents or chemicals that are less likely to harm these polystyrenes (PS) foams. But applying too much paint on the Styrofoam surface will cause melting issues. An extra thick layer of paints will cause an additional force to soften quickly.

What Happened When You Spray Paint on Styrofoam?

Using Styrofoam-friendly spray paints won’t cause any harm to it. But applying solvent or chemical-based spray paints will make it soft gradually and cause stress release.

Its softening temperature range is approximately 240 deg C. When the chemical contacts the Styrofoam, the foam softens and becomes fluid.

Since Styrofoam is not a crystalline polymer, there is no paint melting point or range. Instead, it mainly alters its physical structure rapidly to amorphous, and it will start to collapse.

What Are the Tips to Safe Styrofoam When Applying Paint?

Looking for Styrofoam safe spray paint? If yes, you must find what chemicals are not harmful to Styrofoam. Whether it is a small, moderate, or heavy amount, spray paints include chemicals or solvents. But their types and quantity will vary from one to another.

i) Use Acrylic or Water-based Spray Paints

What safe chemicals do acrylic or water-based spray paints contain? Chromium, manganese, cadmium, cobalt, lead, etc., are the few chemicals you may see in water-based paints.

But it will vary from one brand to another. Some brands may not have one or two chemicals, while a few may use more than these. So, you must know whether the particular chemical will harm spray paints or not.

According to most experts, acrylic or water-based spray paints are the safest options for Styrofoam. These foam-friendly paints don’t contain any chemicals that will harm and melt Styrofoam. They won’t brittle over time. This paint is perfect for repainting a surface. Also, provide better coverage.

Therefore, painters will have more accessibility to painting. It will ensure no or minimal dissolving or damaging issues.

ii) Surface Preparation Is the Key!

Regardless of the surface, you want to paint, appropriately preparing it is crucial. Otherwise, you won’t get a reliable result. So, how to prepare Styrofoam for spray painting?

Make sure you properly clean the foam surface before applying the paint. If the foam has any cracks, refilling them is necessary. You can use a craft sealant like Mod Podge.

Mod Podge Waterbase Sealer

It is one type of super-strong spray formula that will create a high adhesion level on the Styrofoam surface. Apart from concealing cracks, it will protect the surface.

iii) Use a Light Glue (Alternatively)

Another alternative option is using light glue, such as UHU Styrofoam glue, Weldbond, 3M 77, or any ordinary white glue. So, why use this type of light glue?

This foam-friendly glue will protect the surface from having any physical reaction from the chemicals. They add a permanent bonding on the Styrofoam surface for enhanced protection.

Make sure you apply a thin coat. It is better to get spray paint from a reliable brand. Also, don’t forget to go through the instruction manual to apply the glue properly.

What if I Can’t Find a Water-Based Spray Paint?

It is always best to use water-based spray paints for Styrofoam. But you may not always find the type of paint. So, what to do in this situation? Here are a few alternative solutions.

a) Use Regular Acrylic Paint

If you don’t have the accessibility to water-based spray paints, you can use regular acrylic paints. Stir it properly before applying. Don’t add too thick layers of paint.

Avoid using any wire brush to apply spray paint on Styrofoam. Instead, use a foam brush because foam surfaces are pretty soft and slippery.

b) Apply Tempera Paint

Another alternative is using tempera paint, which is also liquid-based paint. It has a heavy pigmentation formula. They work effectively on many porous and foam surfaces.

But you should not always rely on this option. It should be your last choice. This type of paint doesn’t adhere well due to its high susceptibility to water.

c) Use Less chemical-based Spray Paint

If you have no option but to use chemical-based spray paint, choose a safer option for Styrofoam. Read the product label to learn the percentage of solvents.

Apart from that, read some online reviews. Or, take suggestions from someone who had already used the paint on the Styrofoam surface.

Is There A Spray Paint that Doesn’t Melt Styrofoam?

Just because Styrofoam is a highly porous surface doesn’t mean you can’t use any spray paints. Hundreds of spray paints are available to use on this polystyrene (PS) foam.

In fact, some brands make special products for Styrofoam. You can check out this- “spray paint for Styrofoam” article to find a perfect option.

When looking for reliable spray paint for polystyrene (PS) foam, many particular factors need to be considered. You will all find all details in this post. Just tap on it to learn!

How to Prevent Spray Paint from Melting Styrofoam?

Following the right painting approach is as important as using the correct product. Otherwise, it will cause melting issues on Styrofoam.

a) Test Before Applying

Not all Styrofoam surfaces will react similarly. Make sure to test the spray paint in an obsolete piece of Styrofoam to check out the surface reaction. If it seems okay, you can proceed.

b) Prepare The Surface

Surface preparation is essential. It should be free from dust, dirt, and cracks. Your Styrofoam surface may show melting issues due to damage. Use light glue to fill cracks.

c) Use A Quality Primer

Some spray paints may release heat after application. This may soften the polystyrene (PS) foam. Use a quality primer to create a protective layer. The Montana TECH Primer is the one I like best. I have used it several times and have had good results with it. It will safeguard the surface.

Montana TECH Primer

d) Ensure Proper Ventilation

Don’t let the spray paint sit on the Styrofoam surface for too long. So, ensure proper ventilation. It won’t disrupt the natural drying time of Styrofoam.

e) Avoid Applying In Too Hot Temperature

Extremely hot temperatures will force the paint to dry too fast. This will lead to shrinkage issues. If the Styrofoam is massive, you are more likely to notice melting points.

What to Do with Your Melted Styrofoam?

How will you handle the situation if your Styrofoam is already melted? Well, I have a simple solution for you.

When Styrofoam is fully melted, its shape is changeable. So, take a bowl and make a particular shape using paper boards.

Then, gather all the melted Styrofoam and move all of it inside the internal area of the cardboard. Keep all foams inside the area.

Make sure to wear gloves since the melted Styrofoam has chemicals. Let it dry properly, at least for 8 to 10 hours. You can keep it overnight.

Now, see the magic! It will create a hard plastic-type object. Looks awesome, isn’t it? This way, you can utilize melted Styrofoam.

Frequently Asked Questions (FAQs)

Is It Safe to Spray Paint Styrofoam?

Using spray paints on Styrofoam is safe when you use the right product and prepare the foam surface appropriately before applying the paint.

What Is Spray Paint Safe for Styrofoam?

Acrylic or water-based spray paints are the safest spray paints for Styrofoam. But you should check out the product to know whether it contains any harmful chemicals that may cause melting.

Can You Use Rustoleum Spray Paint on Styrofoam?

If the Rustoleum spray paint has a water-based formula, you can use it. But avoid using any Rustoleum spray paints that have enamel or solvent-based formula.

Is Krylon H2O Latex Spray Paint Safe on Styrofoam?

Since Krylon H2O Latex spray paint has an acrylic or water-based formula, you can use it safely on Styrofoam.

Final Thought

Does your query on “Will spray paint melt Styrofoam?” already get cleared? Styrofoam is not a typical surface where you can use any random spray paints. Apart from choosing the right product, adequate preparing the surface is important.

Aside from that, being extra cautious is vital to get a reliable result. Otherwise, you won’t get your expected outcome and may end up damaging the polystyrene (PS) foam. Hopefully, this post has given you a clear overview of the melting issues of Styrofoam.