hi
please help me

I apply gel coat on the mold ( . but some area I applied more gel coat and these area  is thicker than another area ( some area has  mm gel coat and some area has 1.3mm gel coat. is it possible to different thickness effects on the
de-molding of my part from mold?
if yes, please let me know what is it exactly?

2- if i add more cobalt to polyester resin what is the effect of de-molding the part? is good or is not good?

tanks so much

Sometimes with variation in thickness you need to allow more time to ensure an even cure throughout otherwise you can get issues where subsequent resin layers react with the gel causing delamination or surface shrink back and aligatoring type effects.  Most gels will have a sufficient open time for double gelling or layup against to allow sufficient cure time and getting the backing layer on safely. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

If its not coming out the mould, assuming release agent applied correctly, then it probably needs a bit more time to cure. Part cured or green resins tend to grip the mould and can be hard to demould.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant