The Complete Guide to Painting Styrofoam and Making It Hard

The Complete Guide to Painting Styrofoam and Making It Hard

Expanded polystyrene, or Styrofoam, is a petroleum-based plastic manufactured from styrene monomers. EPS foam is the generic name for it. Because it is 98 percent air and has strong insulating capabilities, this white material has the advantage of being lightweight.

It’s not easy to paint styrofoam. This is due to the presence of acetone or solvents such as benzene, toluene, and tetrahydrofuran in many paints and varnishes. They all degrade polystyrene’s structure by dissolving it. All of the air escapes when it dissolves, reducing the EPS foam to nearly nothing.

This post will look at how to deal with hardening and painting styrofoam, both as a craft material and on a bigger scale, in this article.

Table of Contents

EPS Foam’s Uses

Food packaging and the building industries both use EPS foam. It has a strong impact resistance, which is useful for protective packaging, in addition to superior thermal insulation. EPS foam, like other plastics, can be moulded, giving it a wide range of applications.

Its applications in the construction industry include, but are not limited to:

Insulated Panels for Structural Use (SIPs)
Walls, floors, and roofs all benefit from thermal insulation.
Insulation for cavity walls
Insulation from noise

EPS foam works well as a sound insulator. A styrofoam hard coating can be used as a partition wall or wall covering in industrial applications.

Painting styrofoam is a fun activity for youngsters and a great way to decorate your home. Painting and hardening styrofoam is a rather basic craft.

Styrofoam Painting for Craft Projects

Acrylic paint does not disintegrate styrofoam and adheres well to it. Local and internet craft businesses carry acrylics and tempera paint, which are alternative options. There is a vast selection of hues available, and such paints are normally sold in modest quantities of roughly 2 ounces.

Several branded ordinary craft sealants are available in craft stores. With a foam brush or a paintbrush, apply the sealant to the styrofoam object you want to paint first. The easiest way to create an even finish on the surface is to apply a small bit at a time.

Before we can paint the styrofoam object, we need to let the sealant cure. Painting can be done with a foam sponge, foam brush, or soft-bristle paintbrush. Allow 20 minutes for the first coat of paint to dry completely before applying a second coat if necessary.

However, a whole different technique is required for industrial and commercial reasons. To allow paint to be sprayed easily on top of the EPS foam, it requires a strong covering.

EPS Foam with a Rigid Hard Coating

EPS foam coating is produced in a factory setting. A two-component, semi-rigid, 100 percent solids polyurethane polyurea hard coating, designed specifically for EPS foams, is available. It’s administered as a spray to make it easier to reach all portions of the non-uniform surfaces where it’s generally used.

It’s utilised to make signage, ornamental themes, and exhibitions, as well as concrete moulds made from EPS foam. There are applications that don’t require the use of high-pressure spraying equipment to apply the hard coating.

The surface of the hardened styrofoam can be sanded or machined once the hard coating has fully dried. In some situations, EPS foam with a strong hard coating might be a good substitute for fibreglass. Water-based or solvent-based paints can also be used to decorate it.

Required Primer For Rigid Hard Coating

Before applying the coating, you must use a primer, like with most other coatings.

The water-based acrylic latex rubber coating used as a primer for the rigid hard coating stated earlier is formulated to dry quickly. It also attaches effectively to EPS foam surfaces that have been chopped or carved.

Before we apply the rigid hard coating, it seals the surface of carved or moulded EPS foam. The primer prevents air bubbles from forming in the hard coat. When the rigid hard coating is applied, it also prevents air bubbles from escaping from the EPS foam surfaces. You can also read biofit reviews.

Is it necessary to use both the primer and the rigid hard coating?

Only use the primer if you want a smooth surface. In all other circumstances, relying solely on the inflexible hard coating to complete the task will suffice.

The advantage of employing a primer is that it is extremely flexible across a wide temperature range. It also has a strong tensile strength and operates well at sub-zero temperatures.

Using the proper preparations for the material you’re working with is always a smart idea. There are numerous alternative ways to paint styrofoam, but if you want a long-lasting finish with a professional touch, you’ll need to utilise professional supplies.

Solutions for long-lasting

Follow the manufacturer’s instructions when using these professional goods. It’s crucial to apply the primer at a minimum thickness of 7 mm wet or 6 mm dry, for example. You’ll get the most out of its tear and tensile strength features if you do it this way.

Before spraying on the rigid hard coating, the primer, which is white like styrofoam, must cure completely. The primer takes approximately 24 hours to cure at 72°F ambient temperature. High humidity, colder temperatures, and a thicker priming film require more time to cure.

The strong hard coating takes 20 to 30 minutes to harden. After that, you can apply paint to the surface that is suited for bonding with plastic as needed.

Because neither the primer nor the stiff hard coating contain volatile organic chemicals, they are classed as Class 55 non-hazardous solid waste (VOCs). Empty containers must still be disposed of in accordance with federal, state, and local requirements.

Greater Creativity Through Technology

There are no limits to your imagination once you’ve figured out how to paint styrofoam and make it rigid. Shops, restaurants, children’s play centres, advertising points of sale, and even outdoor signs can all benefit from colourful interior decorating.

Look through our magazine for more decorating ideas and much more.

Paint General