Oct 43 min read

What Are The Benefits of Epoxy Hard Coating Over Foam?

How can we give a foam product a stronger and smoother finish? Is Epoxy hard coating the right solution?

Styrofoam (EPS and XPS) might appear hard and strong, however, being about 96% air and only 4% resin, it might be susceptible to damage, breakage, or scrapes and is might not be strong as other foam materials such as High Density Urethane (HDU) foam.

To reinforce EPS or XPS, coating it with Epoxy might be an economical and useful solution.

Styrofoam is a lightweight material that is easily machined, sculpted, and molded into custom shapes, but it lacks strength and rigidity for extended use.

Applying a hard coating to increase its durability may be necessary under certain circumstances, such as:

If the item is intended for outdoor use
If it will be utilized in multiple events or over an extended period, rather than for a single use
If there will be direct contact with people

CNC machined and rpoxy hard coated cowboy hat large foam prop fabricated by WeCutFoam — Epoxy Hard Coating on Oversize Foam Prop

The Epoxy coating can be applied directly onto the styrofoam material and it can enhance its durability and hardness without causing it to melt or dissolve.

This coating is specifically formulated to safeguard against impacts, as well as environmental factors like wind, moisture, and sunlight that could deteriorate the foam structure. It is particularly effective in resisting moisture and humidity by serving as a protective sealant for cracks and small openings, preventing water infiltration that could harm the foam if left uncoated.

Advantages of Using Epoxy Coating

Low moisture absorption - Epoxy absorbs very little moisture.
Low shrinkage - Epoxy shrinks very little.
High thermal and chemical stability - Epoxy has high thermal and chemical stability.
Durability - Epoxy coatings are durable and can withstand intense heat and cold.
Resistance - Epoxy coatings are resistant to water, stains, heat, UV, sunlight, and shocks.
Safety - Epoxy coatings can provide extra traction and stability in hazardous areas like loading docks, ramps, stairs, and aisles.
Cost-effective - Epoxy coatings are cost-effective
Protection - Epoxy coatings provide long-lasting protection from spills, stains, and shock.
Strength - Epoxy coatings are strong and can be used to restore structural strength and weld cracks.
Appearance - Epoxy coatings can provide an attractive, glossy, smooth surface. They also come in clear or in color.

Epoxy hard coating and painting over sie foam props for candy store fabrication of WeCutFoam — Epoxy Hard Coated and Painted Lollipops Foam Props

Disadvantages of Using Epoxy Coating:

At the end of the day Epoxy coating is not expensive and is a nice solution for making props, letters, signs, exhibits and prototypes smoother and stronger than using just the raw foam. However, there are some points to consider:

Temporary solution - It is not an ideal solution if you are looking for permanent long-term protection for your foam creation. If this is the case, you will need a stronger more durable coating solution, such as Polyurea, Polyurethane or Fiberglass.
Not extremely strong - Epoxy can peel, chip break, crack or flake over time and sometimes can discolor as well
Hard to repair - It is not easy to repair it and in most cases, the product might need to be sanded down and hard coated again rather than being recoate

Applying epoxy does not remove any carved details on the foam; it can be layered multiple times for added protection. Typically, we use 1-3 coats based on the customer's requirements and product usage.

The epoxy coating is beneficial as it creates a tough, protective layer over the foam.

It is usually applied by brushing or rolling, although some varieties can also be sprayed. Unlike Polyurea or Polyurethane, it is typically applied in thinner layers, making it a cost-effective option.

Being solvent-free, it can be used on most types of foam. Once the epoxy has cured and completelt dried, you have the option to sand it for a smoother surface before priming and painting, although this step is not necessary as you can paint directly over it.

Here are some letters, props, sculptures and decor with epoxy coating