BassJunky Posted April 10, 2017 Report Share Posted April 10, 2017 Today I poured the second half of a few 2pc molds I had been working on. The issue I came across is that the silicone completely sealed togther and I had to cut them apart, salvaging one maybe two of the molds. i did use a mold release and sprayed it down prior to mixing my silicone (Oomoo 30) how can I avoid this in the future? Quote Link to comment Share on other sites More sharing options...
uttexas Posted April 10, 2017 Report Share Posted April 10, 2017 Silicone sticks to silicone maybe I'm not comprehending, but you have to cut a two piece silicone mold in half after the second half cures no amount of mold release will prevent the silicone from bonding with the other half of the mold Quote Link to comment Share on other sites More sharing options...
Jig Man Posted April 10, 2017 Report Share Posted April 10, 2017 Corn starch applied liberally should keep them from sticking. Quote Link to comment Share on other sites More sharing options...
BassJunky Posted April 10, 2017 Author Report Share Posted April 10, 2017 7 hours ago, uttexas said: Silicone sticks to silicone maybe I'm not comprehending, but you have to cut a two piece silicone mold in half after the second half cures no amount of mold release will prevent the silicone from bonding with the other half of the mold I guess that was a misunderstanding on my part. Every video I watched showed guys just pulling apart the two sides afterwards If I have to cut them part What's the point on making the locking holes. They just sealed togther. Quote Link to comment Share on other sites More sharing options...
Baitjunkys Posted April 10, 2017 Report Share Posted April 10, 2017 Check with smooth on, If you are using oomoo there has to be something to keep them from bonding. They have a excellent technical support if you call them. Quote Link to comment Share on other sites More sharing options...
Anglinarcher Posted April 10, 2017 Report Share Posted April 10, 2017 A proper mold release does allow you to pull two piece molds apart. Silicone does stick to silicone, but it can be prevented. I use UMR from Alumilite for all of my mold release. You can also paint the first mold half with petroleum jelly and that also works very well. If you don't use enough mold release, getting the two pieces apart is a real pain, or impossible, so even when I use UMR I spray, allow to dry, spray again, allow to dry, then mix and pour. Grab your petroleum jelly and make another one and you will have no issues. Quote Link to comment Share on other sites More sharing options...
Roger Linnell Posted April 10, 2017 Report Share Posted April 10, 2017 I read that 2 parts liquid dish soap- 1 part alcohol also works Quote Link to comment Share on other sites More sharing options...
BassJunky Posted April 10, 2017 Author Report Share Posted April 10, 2017 4 hours ago, Baitjunkys said: smooth on, If you are using oomoo there has to be something to keep them from bonding. They have a excellent technical support if you call them thanks, I reached out and they were helpful with some tips. For those interested here is what they told me: "Thank you. We do not have information on how Castin' Craft Mold Release Agent will work with our silicone rubbers. Instead, you will want to use our Mann's Ease Release® 200, applying it using the steps below. 1) Apply a light mist coating over the entire surface of the model and surrounding forms (any surface that will come in contact with the rubber). Do not over-apply! 2) Use a clean paint brush to brush the release agent over the surface of the model and surrounding forms. Make sure that intricate detail, undercuts and hard-to-reach areas are coated as thoroughly as possible. 3) Apply another light mist coating and let dry for 10 minutes. Do not soak your model with release agent. Over-applying release agent will result in tiny bubbles on the working surface of your finished mold (pin-holing) and will be reflected in castings taken from the mold. This is undesirable" Ill give this a shot this weekend, hopefully round 2 is better Quote Link to comment Share on other sites More sharing options...
Anglinarcher Posted April 10, 2017 Report Share Posted April 10, 2017 Quote https://www.alumilite.com/mold-making-casting-how-to-tutorials/molding-casting-beginner-basics#prettyPhoto/3/ Another video of making a two piece mold. Quote Link to comment Share on other sites More sharing options...
Anglinarcher Posted April 10, 2017 Report Share Posted April 10, 2017 https://www.alumilite.com/fishing-lure-making-supplies/making-lure-larry-dahlberg#prettyPhoto/10/ And another one that might be fun for you. 1 Quote Link to comment Share on other sites More sharing options...
wchilton Posted April 10, 2017 Report Share Posted April 10, 2017 You should be ok once you use the correct mold release for silicone to silicone. I'd recommend a test run using a small batch of silicone (no lure model) to make sure you have the process down and can get a clean release. A lot of mold releases contain silicone oil and the silicone rtv just sucks it up. Looks like the mold release you used before is meant for resin or plaster casting, so that's where the problem was. 1 Quote Link to comment Share on other sites More sharing options...
