The Mouldmaking & Casting Forum

Hi all,
I have just made the first part of my 2 part mould. It has set well except for a couple of small parts in centre of the top which are still gooey after 30 hours. Will this cure? If not can I make up some more silicone and pour it over the top? Without adding Vaseline will this stick together? Any help much appreciated! Sean

Hi,
Soft spots in a mould are usually an indication of incorrect or insufficient mixing. I always make it a practice to mix in one container and then pour into another new container to ensure that the silicone that may be adhering to the walls of the original mixing container received a good final mixing. Sometimes low heat applied to a poured mould helps the curing process but generally speaking there is no cure for this condition. My commiserations it happens to all of us at some time. Stan Alderson.