High-Quality Foam Coatings for Small Theming Projects

Foam coats for theming projects like sculptures, props, and architectural shapes are desirable for small fabricators, scene shops, and DIYers alike. In order to protect your foam project in the long term, it needs to be coated, especially if placed outdoors.

There are a range of coatings available, but not all materials will stand the test of time. If you’re going through the effort to make an intricate piece, you’re going to want to make sure it lasts.

What Is a Foam Coating and What Is It Made Of?

A foam coating is a material used to create a durable shell over various foam materials, including EPS, XPS, Styrofoam, or polyurethane. Without a coating, these foam projects are exposed to daily wear, weather, impacts, and other conditions that degrade them.

Some basic coating options are made of a mix of plastic paint, plaster, mortar, or sand, but these materials have a habit of chipping, cracking, or breaking over time. Other materials are dry powder that you mix with water, and it hardens, but they won’t provide a finish as smooth as some other options.

We’ve also seen some people use Drywall mud, but that is another material we wouldn’t recommend. Over time, the material will crack due to temperature changes. It also weighs a lot more than a standard foam coat.

VFI offers several high-end foam coatings for small projects. There are two distinct options we would recommend: brushable hard coats or cartridge-based hard coats.

• VFI-2519 75 D Brushable Hard Coat
• VFI-2626 65 D Brushable Hard Coat
• VFI-6171 70 D Qwik Spray Hard Coat
• VFI-2538 QS 70 D EPS Form Hard Coat

These coatings are polyurethanes. Depending on your requirements, there are both ASTM E84 Class A fire-tested options and options where regulations are not a concern for outdoor themed elements.

The coatings will enhance the performance characteristics of the foam as well as its aesthetics. They also allow you to handle the piece without worrying that it will break from accidents or planned impacts.

Smaller fabricators normally choose to use a brushable hard coat. These coatings are convenient with a simple 3A:1B by volume mix ratio, and they give you greater control over smaller pieces during application. You can easily coat small corners, intricate designs, and curves without diminishing details. Plus, you only use what you need, whereas spraying can lead to wasted material from overspray.

On the other hand, if you’re a small fabricator or scene shop that is consistently working on new projects, the Qwik Spray formula can be more beneficial. The cartridge-based system is great for low-volume applications for projects up to 4 x 4 or 4 x 6 feet in size. Compared to high-pressure spray equipment, the VFI-7500 Qwik Spray Gun is more portable if you need to create theming projects on the go.

What Is the Process of Foam Coating?

Once your foam piece is carved and shaped, you can apply a urethane hard coat directly to the raw foam. Depending on the product you choose, the material will have specific application requirements.

A brushable coating, for example, will require mixing and measuring before application. This part of the application process is where mistakes tend to be made. It’s essential to combine the correct amounts of the two components (A and B sides) for the coating to work and dry properly.

You also have to be wary of the environment you’re working in. Urethane is a moisture-sensitive material. If you do not work in a well-ventilated, temperature-controlled workshop, you may experience bubbling.

For more information and tips on using brushable coatings, check out VFI’s blog.

Alternatively, VFI’s cartridge-based formula doesn’t require mixing. You just uncap the cartridge, put on a static mix tip, assemble it in the gun, and it’s ready for spraying. It’s faster to apply and post-work as it sets in seconds.

The Qwik Spray applicator can provide a smoother, consistent finish that gives the foam piece a more polished look. This finish is especially beneficial for theming applications where aesthetics are crucial to the overall design.

For a step-by-step tutorial on the applicator and cartridge assembly, check out VFI’s How to Use the Qwik Spray System blog.

The hard coat itself is only one step in the theming process. After the hard coat has cured, it should be sanded for a smooth, aesthetically pleasing finish before paint is applied.

An acrylic or industrial-type automotive paint can be used to make them appear more realistic. The hard coats alone are not UV stable, so a top coat is required to prevent them from yellowing and degrading.

How Long Does a Foam Coat Take to Dry?

The time after application that a hard coat needs to dry will depend on the formula and application environment.

VFI brushable coatings are usually ready for sanding and painting the next day, while the Qwik Spray formula dries much faster, and post-work can begin a few hours after application. Ultimately, the coating needs to cure to a desirable hardness first.

Temperature is a big factor in the curing of these coatings. Cooler temperatures below 72°F can delay cure. That is why it’s recommended to work at or above room temperature whenever possible. Just be aware of the relative humidity because a large amount of moisture can affect the finish.

What Is a Foam Coating Used For?

We’ve seen theaters and scene shops across the county use brushable and Qwik Spray foam coatings to protect various projects. From handheld props and small scene elements to outdoor holiday, garden, and lawn décor, theming hard coats are only limited to your imagination.

These coatings are also useful for creating small displays for retail stores, amusement parks, and museum exhibits. A high-pressure sprayable coating should be used if you are working on larger projects.

If the piece will be subject to physical abuse or needs to last a long time, urethane hard coats are your best bet. They improve the abrasion, weather, chemical, and fire resistance of the foam as they encapsulate it entirely.

Most foam coatings are generally not very flexible or pliable. If you’re using softer foam, we also have alternative coatings that can be applied to those surfaces to prevent cracking. VFI-270 70 A Polyurea Spray Coating is a polyurea coating on the Shore A scale, meaning it can maintain the flexibility of flexible surfaces. This material will require high-pressure equipment.

Contact VFI for more information on all our foam coatings for your next project.