This hardener works on all condensation silicones. This T21 hardener from Wacker makes the silicone more resistant to polyurethane and epoxy.
This B component may also be mixed with other condensation B components to achieve a speed of your choice with the properties of the other B components. Common mixtures are:
10% T47 with 90% T21, so for 100 grams of A there is 4.5 grams of T21 with 0.5 grams of T47
Processing
You can easily mix the silicone condensation 20 or other condensation silicones by hand or machine. Mix the A and B components carefully and in the stated ratio.
T21 opinion = 5%, so for 100 grams of A component you use 5 grams of Wacker T21 hardener (B component).
You can use 0.5% less or more hardener. If you use less hardener, curing takes longer and air bubbles have more time to escape. Be careful not to use too little hardener, as the silicone may no longer harden (properly). With more hardener, curing will proceed faster, meaning the mold will be ready sooner. The disadvantage is that the mold will also age sooner and shrink more.
Process the mixture within the pot life (processing time) and never make more than you can process within the pot life. Wait until the mold has completely hardened before removing the mold.
Please note: Pot life (processing time) and demoulding time are highly dependent on the mixing ratio and humidity! When adding more silicone B (harder) or at higher humidity, the pot life and demoulding time become shorter!
Iron, spread or spatula
If you want to spread/spread/iron the silicone on something, you can add Thixo C (0.6%-2%) (usually 1%). Thixo C is a thickener and makes it possible to spread the silicone. You should take into account that in this case the mold must be provided with a support cap. This support cap can consist of plaster cast, an epoxy support cap, or acrylic resin with thickener and glass fabric /
Shelf life
Provided the silicone is stored in closed packaging, cool and frost-free, the shelf life is at least 1 year.
Safety requirements
Use splash goggles, suitable liquid-tight gloves, an apron and work in a well-ventilated area. See Safety Data Sheet for more information
Further important safety information
H-Code hazard statements
H373 May cause damage to organs through prolonged or repeated exposure.
P-Code precautions
P280 Wear protective gloves/protective clothing/eye protection.
P501 Dispose of contents/container to waste disposal.
Documentation
Product information sheet Silicone Condensation 20
EN - Safety Sheet Wacker_Catalyst_T_21.pdf
WACKER Catalyst T series for moldmaking.pdf
