Shelf life of mould making rubber.

[Jim R]

I wanted to make a mould for resin casting. I had some Sylmasta 380 Silicone Rubber and catalyst. I followed the instructions as I've done many times but the mould didn't "set" properly. The rubber stayed rather soft and sticky. I've had the rubber for a few years and the tub was half full.
What I want to know is does the silicone rubber and/or the catalyst have a limited shelf life?
Thanks in advance.
Jim

[Jim R]

Just bumping this up to see if anyone has an answer. Maybe a long shot as even the internet didn't really help.
Jim

[Tim Marlow]

Not something I know anything about Jim, but have you tried asking Sylmasta?

[Neil Merryweather]

Unfortunately yes, about 6 months.....

[Jim R]

Tim and Neil
Thanks guys. I will send Sylmasta an email - don't know why I didn't think of that :rolling: I did suspect that it had degraded as it was old. The rubber is expensive stuff and it goes against the grain to throw it away. Trouble is I don't do enough resin casting to use a whole tub of rubber within it's time.
Thanks again.
Jim

[rtfoe]

Hi Jim, there is a shelf life although I don't know how long so I buy in small quantities if I'm into casting. Storing in a cool dry place helps a little.

Cheers,
Richard

[Niho]

Jim
In my experience a year and the rubber can 'go off' hence me binning 3 lots last year, keep the catalyst though, .....always handy
Nick