Looking for some advice as to why my silicone has never seamed to set.
I've made many many moulds before which have always set within 24-72 hours. 
I use the mould with Xencast Resin.

I used CS25 Condensation Cure Silicone Rubber with MEKP Catalyst, exact same measurements as I always do, in the exact trays with the exact masters (3D printed model car parts). This was in late November and today (2/1/18) the silicone is as runny as it was the day I poured it. It has plenty of Catalyst in, I ususally put maybe even slightly too much to be sure of a quick cure but it's never set. Anyone know of any reason why it won't have set? Only thing I can think of is it was a fresh bottle of MEKP Catalyst and for some reason it isn't right?

Thanks in advance for any help,
Tom
 

Hi Tom,

MEKP is not the correct type of catalyst for CS25 (or indeed any Silicone). MEKP is a catalyst for Polyester and Vinylester Resins and so if you have used MEKP then unfortunately, the silicone won't cure at all. You need the CS25 Silicone Catalyst for the CS25 Silicone.

Sorry to be the bearer of bad news.

+x

 

Rich (Staff) - 1/2/2018 3:26:50 PM

Hi Tom,

MEKP is not the correct type of catalyst for CS25 (or indeed any Silicone). MEKP is a catalyst for Polyester and Vinylester Resins and so if you have used MEKP then unfortunately, the silicone won't cure at all. You need the CS25 Silicone Catalyst for the CS25 Silicone.

Sorry to be the bearer of bad news.

Thanks for letting me know, I always buy the start kit as it always has everything I need in it. This was the first time I’d brought the catalyst separately! I’m always learning and I’ll be buying the correct catalyst from now on! Thank you for your reply