Translucent platinum-cure silicone for mould making, concrete, and podiatry
ZA 13 Mould WT 45 is a pourable, two-component platinum-cure silicone that cures at room temperature to a translucent finished product with a Shore A 13 hardness. The mixing ratio is 1:1 by weight. With a working time of 45 minutes at 23 °C, there is plenty of time to mix, degas, and pour in a controlled manner; the mould can be demoulded after approximately 8 hours.
Key advantages
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Long working time of 45 minutes: provides room to degas and pour larger moulds in one go.
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1:1 mixing ratio: equal amounts of base and catalyst, easy to weigh.
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Low viscosity (4,500 mPa·s): flows well around fine details.
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Elongation at break 440%: ample margin when demoulding undercuts.
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Tear strength 12 N/mm: suitable for repeated use.
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Translucent: you can see the model through the mould.
Typical applications
- Mould making where dimensional stability and precise reproduction count.
- Concrete moulds and artificial stone, thanks to its good compatibility with concrete formulas.
- Podiatry and orthopedic impressions.
- Molds for plaster, coatings and acrylic resins.
- Epoxy, polyester and polyurethane resins only with a release agent, see the note below.
Processing
- Shake the base and catalyst separately to eliminate sedimentation.
- Weigh both components 1:1; use a separate spoon for each component. A deviation of up to 5% will not alter the final result.
- Mix vigorously until the color is homogeneous, ensuring you scrape the bottom and sides.
- Degas the mixture to prevent air bubbles and pour, preferably from a height of about 30 cm.
- Demould after approximately 8 hours at 23 °C. If necessary, use compressed air; do not use sharp objects.
- Additional pouring can be done within 24 hours: the new layer will adhere to the first.
At 40 °C, the working and curing time are approximately halved. At 4 °C, the working time doubles, and the curing process takes about three times as long.
Technical data
Color of base, catalyst, and finished product: translucent. Density 1.07 g/cm³. Viscosity of the mixture approximately 4,500 mPa·s. Hardness Shore A 13 after 24 hours. Tensile strength approximately 3 N/mm², elongation at break approximately 440%, tear strength approximately 12 N/mm. Operating temperature −40 to 200 °C. Typical values after 24 hours of vulcanization at 23 °C, not intended for establishing specifications.
Shelf life of up to 12 months when stored between 5 and 27 °C. Do not swap the caps of the base and catalyst.
Produced by Zhermack S.p.A.
⚠️ Casting polyurethane, epoxy or polyester
According to Zhermack's technical data sheet, you should apply a release agent to the mould before casting epoxy, polyester and PU resins to protect the silicone, and repeat this before every casting when using aggressive resins. Skip it and the resin will attack the mould faster, so you get fewer castings out of it. If you regularly cast polyurethane, choose a silicone the manufacturer itself recommends for it, such as Dow Silastic RTV 3481 R, Wacker Elastosil M 4670 or Wacker Elastosil Vario 40. See the full overview in silicones for polyurethane casting resin; a suitable release agent can be found among our release agents.
Attention: inhibition with platinum-cure silicones
This is a platinum-cure silicone. Curing can be inhibited by sulfur, nitrogen, and tin compounds, latex gloves, some plasticines, condensation-cure silicones, and certain 3D printing materials. The TDS also warns that some petroleum jellies may hinder the curing process. In case of doubt, perform a small test first. Ensure the surface is clean, grease-free, and dry.
