High-detail mold making. Dow SILASTIC RTV-4230-E Silicone Rubber Kit is a two-component silicone rubber. It offers easy release, high elongation, minimal shrinkage, long work time, high strength, and tear resistance, and it is acceptable for food contact. After mixing with its curing agent, it becomes a pourable liquid that forms durable, flexible molds.
Where it excels. Because the mixed rubber pours and captures fine detail, it can produce parts with unusual configurations, severe undercuts, and tight tolerances. Its high strength and tear resistance help molds survive repeated demolding of intricate shapes, extending mold life in demanding reproduction work.
Cure inhibition caution. Like many addition-cure silicones, RTV-4230-E can be inhibited if it contacts certain contaminants during cure, including sulfur-containing and organometallic-salt-containing compounds such as some organic rubbers and other RTV silicones. Surfaces previously in contact with such materials may also inhibit cure. Dow recommends a small compatibility test if there is any doubt, since inhibition leaves the rubber gummy or uncured.
Handling. The two components are combined and mixed, then poured over the master; setup rate for thick sections depends on the size and shape of the piece. As with all silicone rubbers, the master surface should be clean, and the product and Safety Data Sheets should be reviewed before use.
Recommended For
Flexible mold making for intricate parts
Reproducing parts with severe undercuts and close tolerances
Applications requiring high tear strength and low shrinkage
Food-contact-acceptable molds
Production molds needing long working time
Product Details
Product type: Two-part pourable RTV silicone mold-making rubber
Color: White
Key properties: Easy release, high elongation, minimal shrinkage, long work time, high strength, tear-resistant
Food contact: Acceptable for food contact (per source)
Described by source as acceptable for food contact; no formal third-party certification stated
FAQs
What is SILASTIC RTV-4230-E used for?
It is a two-part, pourable silicone rubber for making flexible, durable molds. After mixing with its curing agent, it can reproduce parts with unusual shapes, severe undercuts, and close tolerances. Its high strength, tear resistance, and low shrinkage make it well suited to detailed, repeatable mold-making work.
Is RTV-4230-E safe for food-contact molds?
The source describes the rubber as acceptable for food contact, which is why it is used for molds such as confectionery and bakery forms. Because formal food-contact compliance can depend on the specific application and jurisdiction, users should confirm suitability and review the Safety Data Sheet for their intended use.
What causes cure inhibition, and how do I avoid it?
Addition-cure silicones like this can be inhibited by sulfur- or organometallic-salt-containing materials, including some organic rubbers and other RTV silicones, and by surfaces previously in contact with them. Dow recommends brushing a small amount of catalyzed rubber on a test area first; gummy or uncured results indicate inhibition.
Why is high tear strength important in a mold rubber?
High tear strength allows a mold to flex and stretch during demolding without tearing, which is important when reproducing intricate shapes with undercuts. Combined with high elongation and tear resistance, it extends mold life over many casting cycles, protecting your investment in complex, detailed molds.
How is the rubber prepared and poured?
The two components are combined and thoroughly mixed to form a pourable liquid, which is then poured over a clean master. Setup rate for thick sections depends on the size and shape of the piece. Consult the technical data sheet for mix ratio and cure details before starting production.
