Not sure where you live in the OC, but if your near the coast try West Marine. westmarine.com. I know there is one in Newport Beach and Orange CA. Also a good place to buy West Systems epoxy. A little more than Spruce but you do not have to pay for hazmat shipping.
Crystaliner in Costa Mesa. It's a boatbuilder's supply.
1626 Placentia, Costa Mesa
949.548.0292
All kinds of glass and carbon fiber cloth, West Systems resins and in general a cool place to visit. A heck of a lot cheaper than West Marine (but closed on weekends).