Talk Composites - The Forum for Advanced Composites

Silicone Mould Reaction

http://www.talkcomposites.com/Topic6175.aspx

By Riptide - 5/22/2013 4:04:28 PM

Hi

I am producing a silicone mould using RTV addition cure.  We have created the mould previously using an aluminium plug but needed to be altered.  We have created a GRP plug and used plastercene as an infill.  However, all avound the GRP the Silicone hasn't gone off but has left a sticky and bubbling resedue.  Could you advise why this was and how I can resolve the issue please?

Thanks
A damsel in distress Kim
By Warren (Staff) - 5/23/2013 11:25:34 AM

Addition cure silicone rubbers are susceptible to cure inhibition by a number of products and materials. Take special care to ensure that the uncured silicone does not come into contact with any of the following materials or substances otherwise byou may well find that the silicone does not cure at all in the contaminated areas.

Products with a high moisture content or a high sulphur content are potentially themost damaging.

  • Inhibiting Substances

  • Wood

  • mastic epoxy resin

  • Natural rubber

  • Silicone sealants

  • Neoprene adhesive

  • Vinyl adhesive

  • Transparent wood glue

  • Flexible compact PUR

  • Plasticised PVC film*

  • Foam latex and latex gloves*

  • Cyanoacrylate adhesive* (super glue)

  • Polyester resin

  • Adhesive tape

  • Coachwork polyester mastic

  • Shellac

  • Transparent PVC tubing*

  • Condensation cure RTV

  • CAF (all types)

*  PARTICULARLY ACTIVE

If you used Polyester resin for your GRP plug then that may well be the cause.