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