High Quality Mold For 3 inch Soft Plastics Bait Plastisol Mold 3 inch Hellgrammite Fishing Lure. Bugmolds USA - 1 Cavity Mold. Bugmolds USA offers a high quality stone mold for soft plastics fishing baits. This mold is a single cavity piece that produces one 3in water insect bait soft lure bait amazing for big Trout, Smallmouth and Largemouth Bass. We recommend using lubrication for our stone molds and an injector size for this mold of 5/8in. Create a large variety of soft plastic baits in colors of your choosing! Great inexpensive durable molds that are compatible with plastisol. Make your own fishing lures with Bugmolds USA! Free Shipping in the United States On All Bugmolds USA Products!