SILICONE MOLDS FOR SCULPTURE how to make perfect slice mold for a seamless casting

So let's go ahead and jump right into it. This is John Burns with John Burns Fine Art. In this video I'm going to show you how to make a slice mold and how to create perfect realignment for a perfect casting with minimal seam lines. So in my last video I showed how to make the mother mold and in this first part I'm just deconstructing, opening up the mother mold. We're not going to spend much time on this so if you haven't subscribed to my channel by now I ask that you take the time to do that. Select all notifications so that you can be informed when I release a new video. I'm usually available for about the first 30 minutes after I post a video to answer any questions or comments you might have. And be sure to check out the description where I have my social media links. You can follow me outside of YouTube to see what goes on behind the scenes in my studio. And also there's a lot of products that I use in my studio. Everything from supplies to equipment that you can find there that will redirect you to Amazon and they can get it shipped to your door so you can get started on your sculptures right away. Thanks for coming along today. Okay let me go ahead and get started here. So we are going to cut open this silicone. I'm going to show you a technique that was taught to me and it has made so much of a difference. I used to do these matrix molds and it was basically you'd cast one side of the silicone and have to flip it and cast the other side of the silicone. It's very complicated for someone who's never done it before but this is such a straight on approach it makes it very easy for people that are very right-brained also. So the idea here is that you have your X-Acto blade coming in and with a traditional slice mold like this a lot of times people like to just drag their knife through it and cut the sculpture free and that's not the best way. The best way, this technique that I was taught, is to take the X-Acto blade and stick it in and you're pretending that you are reaching the point on the inside where the silicone meets the sculpture. I mean you're gonna have to guess you know and it's okay in theory it's supposed to be a straight line and this creates a very clean seam line inside. However on the outside we're going to do kind of this back and forth like this and while we do that it creates a zipper on the outside. We're keeping our tip on the line and then going back and forth as we drag it down and what that does is creates like a zipper cut on top so that the mold sits inside of these cradles on both sides and doesn't fall in. If you just do a straight slice it can sink and not line up and you have terrible gaps to fix. This as it sinks okay here's the church here's the steeple just kidding so you put your fingers like this and then when you flip it open in theory the line is straight underneath so it cradles and you have a very clean line that doesn't fall in on it. So that's the theory and let's go ahead and get started here. So my sculpture's in here got the mother mold done in the last video and I have her propped up because I mean she's only held up by her little clay ankles. It's so sad okay um oh yeah. I usually like to cut it open where the the mold opens up because in theory again in theory what happens is when you're putting the two molds together you can see when the teeth are lined up or not. If you put the teeth together and then put the mold on top you can't necessarily see it's just very much a faith thing and it has its limitations. Sometimes you don't find out until after you've cast material. Okay so right here this is a good spot to start. Sharpen your blade or replace it. So I'm going to put my X-Acto straight in and pretend that there's a straight line on the bottom that's pretty much guiding. Now if you find that it didn't go through I mean you'll get to that point like I'm gonna pop this back up this might fall. I'll put that right there just just just in case you want to reference that. Okay so if that doesn't go through this is when you just cut your straight line because you've created the zipper on top and you can see how this creates on both sides and it's not perfectly straight but it's very good and it will hide your lines and these go back together so perfectly that you're not going to be able to see your seam once that's back inside of the cradle. You don't have to worry about trying to get it perfectly lined up and you have to aim so we want to start here perhaps I'm going over the toes and you know what if you can't get it perfectly lined up I forgive you and if you have to make many serrations here a bunch of little cuts that's cool it actually creates registration marks. Well I hope I started the camera. So this Rebond 25 that's just what I chose I'm finding out that with Smooth-On most of the time you know if you get like a 25 or a 30 or a 40 or a 50 that's more important than the type of silicone in my opinion when you're using it for this type of application. See that looks more straight on the inside here the outside is more curved. And I know I'm pretty close to where the mold is because those little holes right there are my nail holes obviously I missed the mark there but up here I'm getting much closer. So here we go we're coming down the back side so we're kind of on the home stretch I hope. Okay so I didn't catch the demolding there of the last part but you can see these serrations here so hopefully I can get this zoomed in correctly you can see how my knife only came in halfway and this is fine too and actually I prefer this to be the way that it works out. So my knife only went in halfway as I was kind of zigzagging back and forth and then when I went to open it up it was only pulling open you know so far and then I would finish cutting with all these little serrations so I didn't have this type of weave cut on the inside it follows more of a straight path you can see it on both sides there. And then when you get down to the legs there you just got to decide I wish I would have gotten that for you. So also what's fun to notice is there's the patch job I did on removing the pipe so that looks pretty sweet there's a little bit of a line here that's going to be a lot easier to fix than a hole in the back and it looks like it slightly wants to let go a little bit right there but that's probably because I had oil on my knife blade I didn't wipe it down before I made the cut but the rest of it looks pretty good I'm pretty pleased with that and so that's one half old Andromeda here so there's where her feet stood and you can see where I had initially made my parting line with the nails on this side and I pulled them out of the rubber you didn't see nail holes anywhere and that's because when you pull the nail out it just closes up around itself so these then the nail holes come down the back and there's my patch job with the piping I would have done a much better job had I you know not had to work around a pipe and silicone and all that to begin with but it is what it is and I'm pleased with that so she's out so let's go ahead and take a look here and get it recradled I'll show you how to do that here's the second half really quick and you know you don't have to cut these completely into two parts you can just cut one side and pull it off but I find that it's easier to work with two parts it does create a with that one arm that would have been almost impossible to pull out there so I went ahead and cut that open pretty good signature came out with no bubbles it's nice the face I'll be able to tell a little better once I have a casting but from what I can see the face looks really good I'm very pleased with it because the problems with faces are typically the nose and the eyeballs where air can get inside this is a tip so you take your Vaseline and what I noticed when I tried to fit this back in the mold there there are some problems you're going to do a casting hopefully not with resin or a more expensive material at first inside of your piece maybe you're going to use wax or plaster that would be ideal to do just a proof of your mold and what I found was one part of my mold when I cradled the second half on top it actually pushed the mold inside the rubber and unregistered it which would have made a very flawed casting so I'm going to put Vaseline on the two halves especially where the two rub as they come back together and what that's going to do is help that slide over it and kind of pop and not create that resistance that forces something out of alignment the idea is that it just sits in there a little better a little easier and if you really if you're really ambitious you can go ahead and grease the whole inside of the mold and what that does is if you have a leak the leaks will shell off easier because if you like cast plaster and it gets out and sticks to your hydrostone sometimes that's very difficult to remove and sometimes it'll permanently deregister the silicone and sometimes that matters sometimes it does not okay I've got my two halves all greased up let's get it put together so I again I greased with Vaseline the plaster mother mold and that's going to allow these to slide into place much more easily see how that just slid right in and almost did like a vacuum into it now one of the first things I notice is this cut on the silicone landed below the line here doesn't make me feel good because I'm not going to be able to see that when I if I would cradle the second half here into that mold and then clamshell the two together so what I'm going to do set that one to the side and put this one here now this one does it too to some degree but because this side is more complex because of this opening here that would be troublesome to try to line up the other way so I'm going to shove it in here while I have the opportunity to look at it and that looks pretty good inside of there I don't know if that can be seen but that line is almost non-existent I mean I can see it if I want to get really creative I can wipe I can take some of this Vaseline off the shell just rub my thumb on it and wipe it on the inside here where the two halves come together and that allows zero resistance of friction anyway so when you're trying to line it up when you get it close and tap it in there get a good light that should just slide right into place better and it did it sits better now there because that's where the cut is right here you see it and with that seam the way that I cut it hopefully we're not going to see any more trouble so I'm going to put this half in here this piece because I'm going to take the second silicone and just lay it in here now I'm going to take my piece out of there and lay it on here see I can lift that up and see that that isn't aligning quite yet so I can get in there at this point and straighten that up and again if you want to you know you can give it a little more Vaseline and you know be careful with this I wouldn't brush Vaseline onto the silicone I mean I might but it's not the best way to do it would be because I wasn't thinking get it on your fingers and then rub it on the edge outward and again this helps reduce friction when the mold is going back together and it would be good right here this is a cut that comes down inside which I'll never see and that is all just straight cuts because of the nature of it I had to come down and cut it open so I don't have the claws to you know hold it like that and again I'm not using a brush because I don't want to find a big clump of Vaseline in my casting and I really don't want Vaseline on the outside of my casting if it does appear I want it to be minimal because my casting it may give me grief when I'm trying to patina so and patina meaning acrylics on the plaster and here's another tip if you see things like not sitting right when you touch it and there's still a gap you see the gap there these gaps that don't close up when you're trying to even tap it they should disappear completely some in some fashion or at least seal but when you see that gap there is something in the way so you could lift that up and find out that something else is out of alignment or sometimes it's a chrome plaster it could be something as simple as that that may have been it because the gap closed here's something to watch out for you see this little piece that causes an opening I've seen other people that do wax work they'll just well I accidentally pushed that in because there's Vaseline there but I've seen them actually put the mold on top of that and just clamp it that deforms the silicone and it deforms the casting so make sure all these little boogers are in their place that it's all locking into place so the next step is to take this half and in theory it should go on it's all greased up so down inside you can see where this seam line see right there but because I've touched the with the tip of my knife that's going to go together a lot better that'll make a much better casting and then that line goes clear up the front of the leg and as far in there as I can reach I'm going to try to just smooth those two together okay so when you feel good about how that lines up go ahead and finish putting on your bolts you can put your bottom on there to store it or you know you can get this greased up right here the opening is pour your material in there you know when it's vertical or horizontal it's better to pour your materials in at this angle so you get less air bubbles than dumping it and then seal it on up get yourself casting how about that so this pretty much wraps it up we're going to get this bolted back together and the next video is going to be a casting so not just a casting but it'll be a casting here and assembling these two parts together so we'll have andromeda one and two I like to label my molds one of two and then two of two so I know how many pieces I'm looking for so I'll get this bolted back together and I'll put it away until I'm ready to do that casting video please subscribe if you haven't subscribed yet please hit that like button that really helps me out a lot if you want to help me even further you may make a contribution or donation at my paypal account at john burns fine art any amount that you feel comfortable with giving is perfect with me I love that you want to help and I do give 10 back to charities at the minimum sometimes we give a little more and that goes to local charities everything from families to children's hospitals to arts and the local community and I also want to say be sure to check out the description down below because it gives you access immediate access really to materials and products and equipment that I use in my studio you don't have to do your own research I've already done it things like wing nuts rasp blades and silicone things of that nature so take advantage I've done the homework and this is free education all day with john burns fine art there's greatness inside you let's unlock it get out of your own way get out of your own way