A Pigment Paste addition rate (by weight) of 10-15% should give sufficient opacity for most applications. They are typically used with surfboard resins to create cool designs and for casting applications such as climbing holds manufacture.
Blend thoroughly by hand or low speed mechanical mixer. Highspeed agitation is best avoided since this may introduce air voids into the final article.
Although not specifically designed for Gelcoating moulds, The fluorescent pigments may need to be dosed at up to the maximum 15% to achieve the required opacity if experimenting with gelcoats for GRP moulding applications. Start off with a couple of layers of fluorescent gelcoat. This can then be backed up with white resin to help with the opacity. We would recommend trialling on a small mould before scaling up.