therustytracks Posted March 3, 2017 Report Share Posted March 3, 2017 I'm about to make my first silicone mold and had a few questions about the process. I have watched a lot of videos and noticed that most people glue the baits or masters down on a piece of glass or other flat surface before pouring the mold. This leaves a flat spot on the bait. I've also seen people make 2 piece molds, pouring one half at a time. Is it possible to pour a small portion of the silicone into the mold form first, place the baits down on the thin layer, then cover them with the rest of the silicone. After it has cured, would I be able to make very precise incisions with a razor blade over each bait and remove them? Would I have issues pouring plastic into the tight incision or could I use something to hold each cavity open while pouring? This seems like it would only leave me a small sliver of plastic to trim off of the baits instead of a big flat spot. Am I correct in this assumption? Quote Link to comment Share on other sites More sharing options...
wchilton Posted March 3, 2017 Report Share Posted March 3, 2017 If you're making a mold using a plastisol bait as the master it's best to have it held in place somehow. Silicone is denser that plastisol and you don't want the bait floating to the top. You can make a one-piece mold with no sprues, etc. like you mention and slice them open with an exacto knife. I've done that. You just may want a little thickness (1/8-inch absolute minimum) on each side to have enough stiffness to maintain the shape of the bait. You also have to be really careful filling those because when you let them close they can ooz/spurt hot plastic. One thing I've done is to mount my master on a thin strip of wood (upside down) so I only get a thin flat region at the top of each bait that is easily trimmed. You basically pour into a long, thin sprue and since the silicone is so flexy it's not problem getting baits out. Quote Link to comment Share on other sites More sharing options...
uttexas Posted March 3, 2017 Report Share Posted March 3, 2017 (edited) Welcome and have fun If your prototype is a firm substance like wood or oven baked clay, pressing it down lightly into a flat sheet of plasticine has worked best for me. Two piece silicone molds are definitely better. When you flip the mold to pour the second half (two piece), you just remove the flat sheet of plasticine. If your prototype is soft plastic/plastisol, I've found that pressing the flattest side onto a length of double sided tape works best. Then, when you flip the mold to pour the second half (two piece), you just remove the tape before pouring. Honestly, if your prototype is soft plastic, one piece POP molds work very nearly as well as two piece silicone molds. Most of your questions are answered in this thread (be sure to click on the links and watch the videos) http://www.tackleunderground.com/community/topic/32516-new-to-making-soft-plastics/ Edited March 3, 2017 by uttexas link added Quote Link to comment Share on other sites More sharing options...
therustytracks Posted March 3, 2017 Author Report Share Posted March 3, 2017 Thanks for all of the great info. I'll take a look at that thread. Quote Link to comment Share on other sites More sharing options...
