370 Silicone Rubber

From: £28.06

Grade 370 is the softest grade of Sylmasta Silicone Moulding Rubber used for creating moulds with deep undercuts

SKU: 370 Category:


Grade 370 is the super soft grade of Sylmasta high tear strength moulding rubber for producing moulds used in the casting of polyurethane resins.

Due to its softness, flexibility and high tear strength, 370 rubber is particularly good for when there are deep undercuts.

Sylmasta Moulding Rubbers are produced to the highest standards for use in industry and model making to produce flexible, highly detailed rubber moulds of all sizes.

The high-quality of Sylmasta silicone rubbers means that once a mould has been taken from the master, it can be used again and again to pour multiple castings using Sylmasta PU Casting Resins.

Moulds made from Sylmasta Moulding Rubber have low shrinkage with no distortion and good dimensional stability. The long pot life means that there is plenty of time to pour the rubber and allow air bubbles to disperse.

Each pack of 370 Silicone Rubber contains catalyst and comes with a free reusable pipette, mixing cup and stirrer. You can order additional accessories from our Casting & Mould Making Accessories section.

370 Silicone Rubber can be purchased as part of our Sylmasta Casting Kits. Each Kit also contains Polycast Resin, Release Agent and all the other equipment needed to create moulds and begin resin casting at a cheaper cost than when purchasing products separately.


“I use 370 Moulding Rubber in all my casting and the quality of the resulting mould is always extraordinary. I get around 20 complete buildings before the mould starts to break up which shows just how durable and long-lasting a mould made from 370 can be.” – Peter Hallett, resin casting historical buildings expert


370 Silicone Soft Moulding Rubber details:

  • Pot Life: 45-120 minutes
  • De-mould time: 10 hours
  • Mixed viscosity: 11,000 mPa-s
  • Shore A hardness: 15°
  • Elongation at break: 622%
  • Tensile strength: 2.8 mPa
  • Tear strength: 20.18 kN/m
  • Young’s modulus: 0.79 mPa
  • Linear shrinkage: 0.46% min.
  • Service temperature: -50°C max.
  • Service temperature: 200°C
  • Colour when mixed: Pale blue

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