[1] Applications of Liquid RTV-2 silicone rubber for molding gypsum cornice is mainly be used as following:
RTV-2 silicone rubber RTV-M 25 is mainly suitable for concret and cement, large gypsum decorations, artificial stone crafts mold making , RTV-M 25 suitable for brushing way which RTV- M 20 suitable for pouring way.
[2]Features of Liquid RTV-2 silicone rubber for molding gypsum cornice :
Two part of RTV-2 silicon rubber: liquid white silicon and curing agent.
Good fluidity and excellent operation.
Good resistance to weather, temperature, aging, acid..
Excellent tear strength, comfortable duplication times.
Cure at room-temperature within 4-8 hours, but all performance will act perfectly when it cure within 24 hours.
[3]Datesheet of Liquid RTV-2 silicone rubber for molding gypsum cornice :
Product | Catalyzed Viscosity:cps | Base Color | Specific Gravity | Mixed Ratio | Shore A Hard | Tensile (Mpa) | Elongation % | Tear KN/m |
RTV M25 | 21,000 | Beige | 1.25 | 100:2 | 25-26 | ≥3.0 | ≥480 | ≥2.5 |
[4] Instructions of Liquid RTV-2 silicone rubber for molding gypsum cornice :
Step One: Take 100g of part A and add 2g of part B and mix the silicon rubber and curing agent evenly.
Notes: Moulding silicon rubber is a kind of flowing liquid and it contains two parts. Part A is a kind of white flowing liquid and part B is the curing agent. Remember to mix part A and part B evenly, otherwise the silicon rubber will be partly solidified and this will give birth to difficulties in your final operation. What’s more, the finished moulds will meet a short life. All of these will cause a waste of silicon rubber.
Step Two: vacuum pumping
Without exception, this step takes less than 10 minutes. Otherwise, it will cause cross linking reaction, and no more further steps will be available.
Step Three: Brushing cast & Perfusion Molding operation
Brushing process:
a. Evenly brush the mixed silicon rubber on the product which is covered with mold spray with a brush or a brush pen.
b. After the cross linking reaction (about 30 minutes), brush a second coat which can increase the tension and tear strength of the mold.
c. Cover a glass cloth on it after another 30 minutes of a second cross linking reaction, and use a brush pen or a brush to avoid any interstices.
d. Cover a third coat.
(Note: if you have high requirements for the tension and the tear strength for the mold, please repeat step c and step d. Hence, the finished silicon moulds will have a good quality and a longer life, which can help you save cost and increase production efficiency.)
Perfusion Molding:
The pouring molding is an easy way to make molds, it’s Slowly and evenly perfuse the mixed silicon rubber into the square frame. After the cross linking reaction.
Any question ,please feel free to contact MS Betty Xu
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