Loki is right on the money, people started using the same casting resin's that are use to make the casts from molds instead of adding fiberglass mat on the inside of their pepped items. Not only did it take less time to do but it also gave you the needed strength and durability for a good base. Also since there trial kits of some casting resin's this can be a relatively cheap way to reinforce your pepped items but it depends on where you purchase your casting resin's from. Hope this helped.