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Casting Resin Baits
3 replies to this topic
Posted 17 November 2009 - 04:06 PM
got a question for you guys who have cast hard ( resin ) baits using a silicone mold.
i ordered some material from Smoothon and the silicone mold appears to be pretty firm. i'll be making a one piece mold of each body segment ( it's going to be a multi-jointed bait like the ones i hand carve. wanting to try another approach. after approx. 300 lures it's getting repetious ).
just wondering how hard it is to get the model piece out of the silicone and how well the mold retains the shape. i plan on using the mold cast container to hold the mold when i pour the resin so i'm thinking it should retain the shape.
any tips, advise appreciated.
Posted 17 November 2009 - 05:17 PM
I have never done a one-piece. I currently have a 3 piece swimbait set up in one 2-piece mold. I've made about 10 different molds so far and having all the pieces in one is definitely the way to go... not sure how this would work with a 1-piece though. For the 2-piece, arrange the pieces side-by-side only have each part configured to have the desired pour vent vertical. In other words, don't just put your pieces side-by-side as they would normally puzzle together. Look at each piece, figure out where you want the pour spout coming in (I try to hide mine in the joint section of the lure). Be sure to add vents for air bubbles too! Put your vents in the areas of the lure that could potentiall trap air as it fills with resin. Don't be afraid of putting several vents in your mold, because its better to have to spend a minute trimming a nice lure than wasting time, money, and effort on a bad pour.
Silicon isn't cheap stuff either so pour as little as necessary. My final mold is rectangular in shape. The reason for this shape is so that the mold sits level when you pour. I put a 2x4 block on each side of the mold and place a clamp on it. I don't actually put much pressure on the sides with the clamp... just enough to keep resin from seeping out.
I'm not saying this is the way you have to do this (like I said, I've never done a one piece)... but its a system that works really well for me.
If you have release agent your mold will definitely last longer. The more detail, cuts, curves in your mold the faster it will wear. I'm sure its even harder on the silicon with a one-piece.
Posted 17 November 2009 - 06:28 PM
Without kwowing what you mean by pretty firm it is pretty easy to get one out. I use the silicone rtv from tap plastics. I pour my mold material around the master with two dowels out the top in a box. When dry pull the box off then at the dowels cut the mold apart till you can squeeze out the master. It is ready to use. I put my pour spouts where it is easy to sand after say like on the nose or top of the back. I will try to post pictures tonight when I get home.
Posted 18 November 2009 - 12:21 AM
Here they are. It does stretch out pretty good. Look at the hardness posted on the spec sheet and you will get the differances this one is 25a shore hardness material. I know it is hard cause you only have one but you can get pretty close to compare. I see that smoothon has different levels do you know witch one you have? This product is not cheap but it takes alot of time to fix the parts every time in a bad mold. With a one piece mold you should have at least 1/4" of wall between the part you casting. If not you could distort your part cause of no support.