CHT QM 272, very hart platinum silicone
Silicone Addition QM 727 – High-Performance Mold Making Silicone
Key Features
Relatively high hardness for silicone rubber
Low shrinkage <0.1% for dimensionally stable molds
Excellent flowability and self-degassing during processing
Suitable for rigid yet flexible molds
Outstanding resistance to epoxy and polyurethane resins
Description
Silicone Addition QM 727 is a two-component platinum-cure silicone rubber that cures at room temperature. With its low viscosity, it pours easily and self-degasses during processing. Over time the material may develop a very slight yellowish hue, but it remains perfectly colorable with pigments.
Thanks to its strength and elongation, QM 727 is extremely versatile. It is particularly suitable for casting candle molds, concrete molds, architectural elements, as well as for producing rubber rollers for transport applications.
Technical Data
Mix ratio (by weight): A:B = 100:10
Pot life @ 25°C: approx. 60 min
Demold time @ 23°C: approx. 12 h
Viscosity @ 20°C: approx. 13,000 mPa·s
Color: Beige
Hardness [Shore A]: 70 (only when cured at 150 °C)
Tensile strength: 5.5 N/mm²
Tear strength: 15.7 N/mm
Elongation: 100%
Density @ 20°C: approx. 1.25 g/cm³
⚠️ Note: While QM 727 cures at room temperature, maximum hardness of 70 Shore A can only be achieved with 1 hour curing at 150 °C.
Processing
The silicone can be mixed manually or mechanically. Mix components thoroughly in the ratio of 100 parts A to 10 parts B (by weight). Process the mixture within the pot life. For best performance, post-cure for 1 hour at 150 °C.
Important Processing Notes
Being a platinum-cure silicone, QM 727 can be inhibited (poisoned) by substances such as sulfur, nitrogen, amines, and certain metal salts. These may be found in:
Latex gloves
Certain clays (plastiline)
Paints and adhesives
Condensation cure silicones and 1-component silicone sealants
Natural rubbers
3D printing resins (especially SLA materials)
If unsure, perform a small test or apply a polyvinyl alcohol (PVA) barrier coat.
Shelf Life
When stored in sealed containers, cool and frost-free, QM 727 has a shelf life of at least 2 years.
Safety
When frequently handling the silicone, use protective gloves and ensure good ventilation. Please consult the safety data sheet (SDS) for full instructions.
