How many square feet (meters) will a unit of brush-on mold rubber cover?

The approximate coverage area depends on how much material is contained in a unit (A+B by weight) and what the material yields on a cubic inches per lb. (or cubic meters per kilogram) basis. Since each brushable mold rubber has a different yield, coverage rates will vary.

The following offers flat-area coverage rates for some of Smooth-On's brushable mold making rubbers. The below values assume a final rubber thickness of 3/8" (1 cm) – 4 layers of rubber applied as directed.

Rubber Product Coverage

  • Mold Max® STROKE - 1 Gallon Kit (11 lbs. / 4.99 kgs.): 4.8 ft² / 0.45 m²
  • Mold Max® STROKE - 5 Gallon Kit (55 lbs. / 24.95 kgs.): 24 ft² / 2.23 m²
  • Rebound™ 25 - 1 Gallon Kit (18 lbs. / 8.16 kgs.): 7.8 ft² / 0.72 m²
  • Rebound™ 25 - 5 Gallon Kit (90 lbs. / 40.82 kgs.): 39.2 ft² / 3.64 m²
  • Rebound™ 40 - 1 Gallon Kit (18 lbs. / 8.16 kgs.): 7.8 ft² / 0.72 m²
  • Rebound™ 40 - 5 Gallon Kit (90 lbs. / 40.82 kgs.): 39.2 ft² / 3.64 m²
  • Brush-On® 35 - 1 Gallon Kit (13.4 lbs. / 6.08 kgs.): 5.3 ft² / 0.49 m²
  • Brush-On® 35 - 5 Gallon Kit (75 lbs. / 34.02 kgs.): 29.9 ft² / 2.78 m²
  • Brush-On® 40 - 1 Gallon Kit (18 lbs. / 8.16 kgs.): 7.9 ft² / 0.73 m² 
  • Brush-On® 40 - 5 Gallon Kit (90 lbs. / 40.82 kgs.): 39.5 ft² / 3.67 m²
  • Brush-On® 50 - 1 Gallon Kit (18 lbs. / 8.16 kgs.): 7.9 ft² / 0.73 m²
  • Brush-On® 50 - 5 Gallon Kit (90 lbs. / 40.82 kgs.): 39.5 ft² / 3.67 m²
  • Brush-On® 60 - 1 Gallon Kit (18 lbs. / 8.16 kgs.): 7.8 ft² / 0.72 m²
  • Brush-On® 60 - 5 Gallon Kit (90 lbs. / 40.82 kgs.): 39.2 ft² / 3.64 m²

Doing the Math

Below are some examples for how these coverage rates can be calculated by hand. The first step is to calculate the total cubic inch yield of a kit (Net Weight times Specific Volume). Then, divide out the mold thickness (3/8"). Lastly, convert square inches to square feet.

How many square feet will one 5-gallon unit (90 lbs.) of Rebound® 25 or 40 brush-on silicone rubber cover at 3/8" thickness?

  1. 90 lbs. x 23.5 cubic inches per pound = 2,115 in³
  2. 2,115 in³ ÷ 0.375 in. (3/8") = 5,640 in²
  3. 5,640 in² ÷ 144 in²/ft² (no. of square inches in a square foot) = 39.2 ft²

39.2 square feet is the coverage of a 5-gallon unit of Rebound® 25 or 40 applied 3/8" thick.

One-gallon Unit (18 lbs.) Coverage

  1. 18 lbs. x 23.5 cubic inches per pound = 423 in³
  2. 423 in³ ÷ 0.375 in. (3/8") = 1,128 in²
  3. 1,128 in² ÷ 144 in²/ft² (no. of square inches in a square foot) = 7.8 ft²

7.8 square feet is the coverage of a gallon unit of Rebound® 25 applied 3/8" thick.

How many square feet will one 5-gallon unit (75 lbs.) of Brush-On® 35 urethane rubber cover at 3/8" thickness?

  1. 75 lbs. x 21.5 cubic inches per pound = 1,612.5 in³
  2. 1,612.5 in³ ÷ 0.375 in. (3/8") = 4,300 in²
  3. 4,300 in² ÷ 144 in²/ft² (no. of square inches in a square foot) = 29.9 ft²

29.9 square feet is the coverage of a 5-gallon unit of Brush-On® 35 applied 3/8" thick.

One-gallon Unit (13.4 lbs.) Coverage

  1. 13.4 lbs. x 21.5 cubic inches per pound = 288.1 in³
  2. 288.1 in³ ÷ 0.375 in. (3/8") = 768.27 in²
  3. 768.27 in² ÷ 144 in²/ft² (no. of square inches in a square foot) = 5.3 square feet

5.3 square feet is the coverage of a gallon unit of Brush-On® 35 applied 3/8" thick.

How many square feet will one 5-gallon unit (90 lbs.) of Brush-On® 40 or 50 urethane rubber cover at 3/8" thickness?

  1. 90 lbs. x 23.7 cubic inches per pound = 2,133 in³
  2. 2,133 in³ ÷ 0.375 in. (3/8") = 5,688 in²
  3. 5,688 in² ÷ 144 in²/ft² (no. of square inches in a square foot) = 39.5 ft²

39.5 square feet is the coverage of a 5-gallon unit of Brush-On® 40 or 50 when applied 3/8" thick.

One-gallon Unit (18 lbs.) Coverage

  1. 18 lbs. x 23.7 cubic inches per pound = 426.6 in³
  2. 426.6 in³ ÷ 0.375 in. (3/8") = 1137.6 in²
  3. 1137.6 in² ÷ 144 in²/ft² (no. of square inches in a square foot) = 7.9 ft²

7.9 square feet is the coverage of a gallon unit of Brush-On® 40 or 50 applied 3/8" thick

How many square feet will one 5-gallon unit (90 lbs.) of Brush-On® 60 urethane rubber cover at 3/8" thickness?

  1. 90 lbs. x 23.5 cubic inches per pound = 2,115 in³
  2. 2,115 in³ ÷ 0.375 in. (3/8") = 5,640 in²
  3. 5,640 in² ÷ 144 in²/ft² (no. of square inches in a square foot) = 39.2 ft²

39.2 square feet is the coverage of a 5-gallon unit of Brush-On® 60 applied 3/8" thick.

One-gallon Unit (18 lbs.) Coverage

  1. 18 lbs. x 23.5 cubic inches per pound = 423 in³
  2. 423 in³ ÷ 0.375 in. (3/8") = 1,128 in²
  3. 1,128 in² ÷ 144 in²/ft² (no. of square inches in a square foot) = 7.8 ft²

7.8 square feet is the coverage of a gallon unit of Brush-On® 60 applied 3/8" thick.

How many square feet will one 5-gallon unit (55 lbs.) of Mold Max® STROKE cover at 3/8" thickness?

  1. 55 lbs. x 23.5 cubic inches per pound = 1,293 in³
  2. 1,293 in³ ÷ 0.375 in. (3/8") = 3,448 in²
  3. 3,448 in² ÷ 144 in²/ft² (no. of square inches in a square foot) = 24 ft²

24 square feet is the coverage of a 5-gallon unit of Mold Max® STROKE applied 3/8" thick.

One-Gallon Unit (11 lbs.) Coverage

  1. 11 lbs. x 23.5 cubic inches per pound = 259 in³
  2. 259 in³ ÷ 0.375 in. (3/8") = 691 in²
  3. 691 in² ÷ 144 in²/ft² (no. of square inches in a square foot) = 4.8 ft²

4.8 square feet is the coverage of a 1 gallon unit of Mold Max® STROKE applied 3/8" thick

Disclaimer
This FAQ article is offered as a guideline and offers possible solutions to problems encountered during mold making and casting. No warranty is implied and it is up to the end user to determine suitability for any specific application. Always refer to the provided Technical Bulletins (TB) & Safety Data Sheets (SDS) before using any material. A small scale test is suggested to determine suitability of any recommendation before trying on a larger scale for any application.