|
Group: Forum Members
Posts: 11,
Visits: 65
|
Hi
If you are casting a full piece in a silicone mold,you might be experimenting a shrinkage issue due to exotherm reaction,wich is fairly normal in clear poliester.The reaction takes place from the inside to the outside,and polyester in full pieces will kick faster where there is more mass concentration of material.As silicone has its self release properties,when it shrinks,it separes easily from the mold surface,the interior of the piece cures faster than the surface,and this gives this wrinkled surface in my experience.
We cast clear polyester in silicone molds often in my studio,for making fake eyes for example.If we get a wrinkled surface,we have to sand and polish(with special paste).I have sometimes tweaked the cathalist ratio.For bigger batches than 100-200 gr using the minimum cathalist recommended by the manufacturer,and for smaller batches,you can try increasing it(you will have to test).But it will all depend on the material mass concentation you have,and your room temp.This material wont work the same in cold winter than in hot summer.
Clear PU resins can be an interesting option to avoid these issues.
Hope it helps
|