Fibreglass Supplies Premium Addition Cure RTV Silicone Rubber is high-strength, professional-quality, silicone mould-making rubber designed for detailed casting, crafting and general mould production. Ideal for makers, sculptors and fabricators, RTV silicone is formulated for easy hand mixing and delivers excellent results without the need for specialist equipment.
RTV silicone's low viscosity allows it to flow smoothly into mould boxes and around intricate shapes, making it perfect for capturing fine surface detail on figures, art objects, sculptures and decorative components. The silicone and catalyst blend easily and can typically be used without vacuum degassing, making it a reliable option for both beginners and experienced mould makers.
Once cured, this addition cure silicone offers a Shore A hardness of 35-45, giving it a soft-to-medium feel that balances flexibility with durability. Its high elasticity allows for easy mould release, even from complex or undercut parts, while maintaining strong tear resistance for repeated use.
For best results, add the catalyst to the silicone, mix thoroughly, and allow the mixture to stand for a few minutes so trapped air can rise before pouring. When working with very fine detail and no degassing equipment, the silicone can also be brushed into detailed areas first, helping to reduce bubbles and improve surface accuracy.
This RTV silicone offers a generous working time of 40-60 minutes, allowing plenty of time for careful mixing and pouring. Cure time will depend on ambient temperature, but moulds are typically ready to release after 12-24 hours. Always ensure the silicone is fully cured and dry before demoulding, and allow extra time in colder conditions.
Mixing Ratio:
Working & Cure Times:
Code: 11097
Fibreglass Supplies use Royal Mail, APC Overnight and the National Hazardous Pallet Network for our Next Day Delivery Services.
Royal Mail
Orders of up to 2kg will usually be sent using a Royal Mail First Class Service for National Next Day Delivery.
APC Overnight
Orders over 2kg and up to 30kg will be sent using a Fully Tracked Next Day Service using APC Overnight. Some smaller Roofing Kits that weigh up to 30kg in Total would be sent on this service. This includes Resins, Gelcoats and Topcoats which are classed as Hazardous and are decanted into 5kg Tins or Pales to comply with the Transportation of Hazardous Goods Act.
Pallet Network
All our larger orders by weight would usually be sent using the National Pallet Network. Non Hazardous Items can be sent using either the Pallet Network or APC Overnight.
All Hazardous goods over 30kg (which includes Roofing Kits over 30kg in total weight) are usually sent using the National Pallet Network on a Fully Trackable Next Day Delivery Service.
Click & Collect
All orders are eligible for Click & Collect. Pick up your items conveniently from our Cattedown Store, available Monday to Friday between 7:30 am and 4:30 pm (excluding Bank Holidays).
NB - Please note that our Direct Control of the Delivery Element extends to making sure we pick pack and dispatch all orders on time. As we have no Direct Control over the performance of any individual courier we would not be responsible for refunds due to the late arrival of any order.
We always work hard with customers to overcome any issues that arise so please call us if you do have any concerns with regard to tight delivery deadlines so that we can provide great advice if needed.
Please read our Returns policy laid out below.
Under the Consumer Contracts Regulations 2014 you are entitled to return goods within 14 days of delivery for a refund of the cost of the goods. The delivery costs and any packaging are not included in the refund. The returned goods should be in the original containers and unopened. It is the customers responsibility to pay for the cost of returning goods to our Business Premises.
Some of our products are made to order and as such once ordered are non refundable and non returnable. These include coloured gelcoats, topcoats and resins.
These Consumer Regulations do not apply to business purchases (B2B). However we will always help in any way and look to find a suitable and mutually acceptable solution should any issues arise through the order process.
It is the customers responsibility to understand the suitability of the product before its use. Technical and Safety Data Sheets are available for all products where applicable. These can be found on most product description pages or if not are available on request. If you are unsure please do not hesitate to contact us for expert advice and product suitability and application.
To organise a return please contact us on the following.
