I wish to replicate some vehicle amber indicator lenses. I assume I will make the mould from silicone rubber. What is the best casting material for these please?

[THANKS WARREN]

Hi Ray,

I believe you're now in contact with my colleague Rich in our technical department and that you're aware we have a Water Clear Polyurethane Casting Resin which would indeed be ideal for you and also that you're going to have a go with our Water Clear Polyester Casting Resin as a more cost effective trial whilst you familiarise yourself with the process.

In both instances, done right you could get some great results casting these parts in water clear resin but, as you'll find out, water clear casting is more 'fussy' than most casting processes and will expose issues to do with air entrapment, cure temperature and moisture presence more than most.

Rich has suggested our Addition Cure Silicone Rubber for the mould itself. Condensation cure rubbers (like our CS2) don't work well at all for water clear casting because they harbour moisture which will react with the clear resin resulting in a tacky surface to the mouldings and can exaserbate air entrapment. Whilst the water clear polyester can be cast without the need to degas; when you make the transition to the polyurethane you will need to degas the resin to get a bubble-free perfect casting.

I hope this helps and look forward to working with you.

Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales