Cover styrofoam with gypsum using two methods

Especially in modeling Styropor is used as a design tool. To model buildings and landscapes, it is common practice to apply plaster. Gypsum is a frugal material that easily adheres to clean Styrofoam surfaces. In aquaristics and terrariums, gypsum is not suitable due to its solubility in water.

Two construction paths

When coating styrofoam with gypsum, two approaches are possible.

1. Free modeling similar to plasticine
2. Pour into molds and apply the styrofoam as a carrier

In general, the Styrofoam does not need to be worked to apply gypsum. Rough blanks on the mold sizes are sufficient. Precise adjustments can be made on the dried plastered component.

Stir and color plaster

In order to make the gypsum mixture homogeneous, the gypsum should always be stirred into water. If water is added to dry gypsum, lumping is unavoidable. After stirring, the gypsum compound is allowed to rest for about one minute. Then stir again for a creamy consistency.

As the percentage of gypsum increases, the gypsum compound becomes tougher and resembles softer clay. For free modeling, this consistency is required. When stirring, it is important to always follow a stirring direction when distributing the dye. This keeps the gypsum fluid for a longer time and the added color has more time to spread evenly.

Dry color pigments in powder form are not suitable for dyeing gypsum. Suitable liquid and mixable colorants are:

  • Ayrylfarbe
  • Batik Color
  • Food coloring
  • Easter eggs color
  • watercolor

Use molds and put on polystyrene carrier

In order to produce components such as facades, walls and walls, the plaster is poured into a negative mold made of silicone. Subsequently, the Styrofoam is pressed and forms the carrier element.

The silicone mold must be sprayed with a water-detergent mixture to allow the subsequent break-free detachment of the gypsum. The styrofoam component is pressed onto the shaken and thus compacted sprue. Drying hardens the surface. It can be smoothed by a thin plaster during or after drying.

Tips & Tricks

If you do model making, you can easily recycle styrofoam from other uses for many structures and models. Collect pressed mold packaging elements, such as those found in electrical appliances such as televisions and food processors.

Artikelbild: kojala / Shutterstock

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