10pounder Posted November 1, 2007 Report Share Posted November 1, 2007 I just bought some RTV to make molds for some soft plastics and used it for the first time last night. I noticed this morning that the baits slipped down into the silicone too far. Should I wait a certain period of time before placing the bait into the material so that it has a harder consistency? I'm a little unsure of the best process. I was left having to cut around areas that had gone too deep and had silicone cure over top of where I should be pouring. Quote Link to comment Share on other sites More sharing options...
BBC Posted November 1, 2007 Report Share Posted November 1, 2007 The best way to make a mold with RTV is to attach (glue) the lure down and pour the RTV over them (so you're making the mold upside down). I usually glue the lures to the shiney side of a cereal box with a Duco cement (I got it at Wal-Mart). Then I cut strips of the cereal box and makes sides for the mold. Make sure you tape all the seams (bottom and sides) of the pieces of the cereal box so the RTV doesn't leak out (I just use masking tape). Also, make sure the shiney side of the box is going to be against the RTV or it'll be difficult to pull the cardboard off the RTV after it cures. This is the process I've always used. I found it in a thread on here when I started. It's easy and cheap to make a jig for a mold this way. Also, you have a lot more control over the orientation of the lures because you are physically gluing them where you want them (you can make sure they are straight and spaced the way you want them). Hope that helps. Eric Quote Link to comment Share on other sites More sharing options...
thryb Posted November 1, 2007 Report Share Posted November 1, 2007 10pounder are you talking about a 1 or 2 pieces mold ? Quote Link to comment Share on other sites More sharing options...
10pounder Posted November 1, 2007 Author Report Share Posted November 1, 2007 In this case it's a one pc mold, but I would interested in any pointers you have on 2 pc as well. Thanks. Quote Link to comment Share on other sites More sharing options...
nickcalderone Posted November 2, 2007 Report Share Posted November 2, 2007 10pounder, I have made molds both ways...that is glueing the bait to the bottom of the mold and pouring over it...and I have also used the method you used which is to pour the RTV and then place the bait upside down into the RTV. In my opinion, I have actually had better results placing the bait into the RTV as it is curing. I had to do a little trial and error, but with the type of RTV I have been using, it takes approx. 40 mins. at 72 degrees F. At that time, the RTV is firm enough to allow me to place my clay masters onto the RTV and it will stay put without sinking down too far. Then, I can tap the bait a little to push it flush with the surface of the RTV. You just have to have a light touch. After you get it exactly the way you want it, DO NOT TOUCH OR MOVE THE MOLD as this will cause settling of your bait and it will sink. You may have to experiement with different wait times, as different RTV's solidify at different time intervals. I have been using Alumilite RTV. As for a two part mold, if you do a search on 2 part molds, you will find plenty of examples both here and through google. The same basic principles apply, you just leave your bait in the RTV after it cures, apply a release agent, then pour your RTV on top of the bait and cured RTV. Let it set overnight, and then pry apart in the morning. You may want to add "keys" which actually help to align the mold...thats up to you. Good luck and don't get discouraged. You will find plenty of help and encouragement on this site! Lots of good folks. Quote Link to comment Share on other sites More sharing options...
10pounder Posted November 2, 2007 Author Report Share Posted November 2, 2007 Thanks so much for the information. I'm having alot of fun with this, but trying to minimize the mistakes along the way. Quote Link to comment Share on other sites More sharing options...
