How To Use Flex-Coat



1. Carve your foam prop or set. Give the foam a light sanding for a better surface hide. This helps the Flex-Coat adhere to the surface.

2. Working with Flex-Coat is a time sensitive process. Flex-Coat has been formulated to set up and cure like Portland cement. This means that the batch size you mix up will need to be used or discarded. Once mixed, you can't store Flex-Coat for a later project. The Brutal Rust team recommends working with small batches to minimize product waste.

3. At Brutal Rust, we use three (3) different mix ratios that are dependent on how thick or thin we want the Flex-Coat to be.

[The Brutal Rust Team always mixes with (1) Cup and (1/2) Cup measurements]

  • Thick Flex-Coat is for creating heavy mortar between faux bricks.

    THICK: 1:3 Ratio of Water to Flex-Coat.

  • Medium Flex-Coat High traffic or high usage sets and props. 

    MEDIUM: 1:2.5 Ratio of Water to Flex-Coat.

  • Thin Flex-Coat is used for background walls or objects with low traffic and usage.

    THIN: 1:2 Ratio of Water to Flex-Coat.


  • Pour (1) Cup / 8oz water in small bucket
  • Mix in (2) cups / 16oz of Flex-Coat and stir
  • Wait 3-5 minutes
  • Use Flex-Coat 

4. After mixing, let the Flex-Coat sit for 3-5 minutes before using.

5. Once mixed, use a cheap chip brush to paint or stab Flex-Coat onto your project.

6. The drying time depends on the temperature and humidity in your area. The Flex-Coat will go from a dark charcoal gray to an almost dull white/gray when fully dry.

7. If you’re staining the Flex-Coat, We recommend waiting about 10-20 minutes after applying the Flex-Coat. Flex-Coat will age nicely with our line of Brutal Decay stains and Highway Rust patina. 

8. The Flex-Coat will also take stain once fully dry. To do this, spritz the dry Flex-Coat with water and then apply the stain.



1. Using Flex-Coat on PVC is easy to do. If you are going to put the PVC in a high traffic area, you might want to try the following tips. 1. Prime the PVC with self etching primer or alternatively you can use 3M 77 Spray Glue to create a hide. Simply spray the project with 77 and let it dry. This will create enough surface texture for the Flex-Coat to adhere.