Silicone Types

Platinum vs Tin Cure

Platinum and tin cure silicones (sometimes reffered to as condensation and addition cure) are the two main categories of silicone, they each have a wide range of properties available and which is best often comes down to personal preferance / use case.

Platinum Silicone (Addition Cure)

• Low shrinkage - molds retain the correct shape even over long periods of time

• Cure inhibition - platinum silicones are much more prone to have negative reactions with other materials stopping them from setting. 3D prints created by SLA / resin printers have a tendancy to prevent curing unless thoroughly cleaned first.

Recomended Platinum Silicones

Smoothon Moldstar 20T

• Fast cure time
• Good amount of stretch making it good for parts with slight undercuts

• Short potlife, means you have to be fast to get your moulds filled
• Part A and B are the same colour making it hard to see if fully mixed. (adding a small amount of resin dye can help) Moldstar 30

• Easy to mix 1:1
• Good Mold life - 20-50 castings
• Long pot life - 45 minutes

• Slow cure time - 6 Hours

Tin Silicone (Condensation Cure)

• Less likely to have issues with cure inhibition.

• Molds will shrink over time and lose dimensional acuracy.

Recomended Tin Silicones

MoldMax 29NV

• Good amount of stretch / tear resistance
• Good to use on SLA prints

• Need scales to measure 1:10 mix ratio
• Looks like white chocolate - might be tempted to eat

Oomoo

• Easy to mix 1:1
• Readily available

• Tears Easily
• Short mould life 10-20 casts