okay welcome back to diode press I'm Graham so today's video we're gonna do a little bit of mold making so going to take this plastic cassette tape and we're going to make a two-part silicone mold and then hopefully by the end of the video we'll be able to pour plaster into and have exact casting of the cassette tape and so this video is really just one part of a larger printmaking project that I'm working on let that be nice to break this out separately of how to make a two-part mold and you can really use this technique for any object you're trying to cast you know in my case I'm doing a cassette tape but it'll work for anything you just have to modify the mold and the steps you take based on whatever object you're going to be using so make sure to subscribe to the channel to keep up when I post the videos showing you know what I use this mold for in the future and let me know down in the comments if you have any questions and let's jump into the video so depending on what you're going to use for your casting you might not need to do this step but since I'm using a cassette tape I don't want the silicone to fill inside the tape when I pour it in so I'm going to go ahead and take out everything inside the cassette tape and then fill it up with clay that kind of seal it off so now the insides full of clay I'm going to go ahead and seal up some of the smaller cavities around the tape because you don't really want small pockets for the silicone to go into little just break off when you peel it off so this helps smooth out all those transitions so this step is really specific to my particular project but I need to have this square shape part of my mold so I'm gluing on a piece of linoleum onto the tape and so when I pour my silicone it's all part of that mold but if you're just making a two-part mold of an object you don't obviously have to worry about this but it'll make sense why I need this in the next part to this video and here's my final object ready to start making my mold out so everything's sealed up pretty well there's no deep pockets for the silicone to go in and break off when I pour it and everything's just sealed off and smooth so I'm making a two-part mold and you can make multiple part mold but depending on your object how you organize the pieces you know what angle it's going to be at that's all very specific to your object but for this piece I'm going to have the tape just laying horizontal so first I need to make a bed of clay for the object to sit on oh and I should mention any clay that you use is going to be in contact with the silicon you have to make sure it's sulfur free clay because the sulfur will interfere with the curing of the silicon so depending on the uses of light your molds going to be for and that the kind of the quality the silicone you're gonna use for your mold that's gonna affect how much you know thickness you need I'm using a pretty low grade silicone you know it's really more of a hobby level silicone so I'm gonna make the mold extra thick because I want to hold up over time and I don't want to fall apart from peeling it up over and over so there's gonna be quite a bit of real estate around my cassette tape that's ultimately going to become the silicone mold so the white base under my clay is a piece of foam core board and so I'm also gonna build four walls around the clay with some more foam core and just hot glue and you want to make sure you seal this up so none of the silicone can leak out through any gaps and foam cores are you know a quick cheap material to use if you're going to be making multiple molds in you can use more Hardy products this step is really important you want to make the seam along the edge of your object as smooth as possible so it's really easy with this cassette tape because there's already an existing seam so all they have to do is make sure my level of the clay matches along that seam and so when I make my two-part mold it'll fit together perfectly and you'll have a seam line that matches exactly like the cassette tape and so depending on your object you're gonna have to kind of figure out where you want the seam to be along the edges but just make sure you make it really really clean and here you can see the edge of my clay meeting right up against the edge of the tape along that seam line and so depending on your objects shape you're gonna have to make a pour spout and maybe some vent holes so to make my pour spout I'm using a one inch dowel and I'm just hot gluing it on to the top of the tape since this is a flat object it's gonna have a tendency to get air bubbles trapped inside of it so I'm using a couple of glue sticks and making some vent holes and hopefully this will help get some of the air out of that once I've pour the silicone in if it's more of a rounded shape a lot of the air will come right out of your pour spout but you always want to make sure you have some sort of either vents in your highest spots or have the pour spout in the high spot of the mould and so if I was just casting this cassette tape just to have a cast of it I probably would have cast it you know vertically rotated 90 degrees up from where it is so that way all the air would travel up to the thin corner of it but I really need to lay flat for what I'm going to be using this mold for in the next video so that's why I'm having to kind of go through this extra step of adding extra air vents so I'm making these vents out of the glue sticks but ultimately this is going to be the back of the casting and no one's ever gonna see it so even if there are a few air bubbles it doesn't really matter but just for the structural integrity of your piece you want to make sure you can get out as much air as you can when you pour it now it's time to put in some registration keys along the perimeter of my mold so I'm putting one every couple of inches or maybe every inch along the perimeter and I'm just making sure that they're on nice dome shape and when you pour the silicone it'll fill in these small domes and then when you pour the other half it'll give us something to key on to and you'll see in the next steps how that works out and so most likely you'd be fine just using the registration keys alone but I'm going to go ahead and put in this groove along the perimeter just as an extra measure for you know registration it also makes a lot easier to figure out which side goes where when you're putting it together if you just have lots of registration marks you just want to make sure that the area between your registration keys and the part you're casting is far enough away now we don't have any thin spots in your mold and the last thing before we move on to pouring the silicone it's just to make sure you clean up the edges and make sure there's nothing in there you don't want you know any bumps or ridges because whatever you have here is gonna show up in your silicone mold alright and here's all the materials you're going to need to make the two-part mole and so I'll have a link in the description box below to a blog post that'll have all this listed out for you so the silicon I'm using is called EMU 30 it's really forgiving silicone to use but one thing you have to remember is to stir each container really well before you mix it and do anything else because the separates out in the jar is a lot from sitting on the shelf or whatever so you want to make sure you follow the directions I think you mix it for at least a minute or two minutes before you move on so I'm not sure if I mentioned it but the amount of material you're going to need to make your mold really depends on the object you're making the mold of and how thick you want it to be so that's something you're gonna have to figure out but you can use things like you can fill your mold cavity with rice and figure out what that volume is or you can just do the the length width and height of the mold cavity and convert that to the volume of material so there's really a lot of ways to do it in this case I have a lot of this silicon material I'm just going to make an extra-thick mold and not really worry about it so the best part about that mumu 30 is it's a one to one mix ratio so you don't have to worry about weighing it or anything you just in my case I'm pouring 10 ounces of the pink and then another container I'll pour 10 ounces of the blue so since it's a two-part silicone as soon as you pour the materials together it's going to start the chemical process so you want to pour them in separate containers for your measurements and then pour the blue into the pink since the blue is a lot more liquid it's much easier to get out of the container and then just follow the directions and just mix it really well so ideally once you get it mixed really well in that container you want to scrape it out into a new clean container because no matter how hard you try to mix you're never gonna get all the edges clean you can even see through the plastic you can see the blue and the pink areas but it all looks pretty well mixed so by pouring it into a new container you can make sure that everything in there is fully mixed and you don't have any uncured part to your mold when you're done but the nice part about all this is since it is silicone once it's all charity in these containers you can peel it out and you can reuse these containers as many times as you need because in reality even the part that looks unmixed in the container it does cure but I wouldn't trust that in my actual mold so when you're mixing up your silicone you want to make sure you're folding it together I'm using a flat wood stick here you don't want to beat it or you know really stir it up and introduce air bubbles because we're not going to be doing any kind of vacuum degassing or anything in this we're just gonna mix it and then pour it so just try to make sure you mix it well but don't be too vigorous with it and it takes a while to cure so you have some time to make sure you get it good and so now it's time to go ahead and pour your mold and so you can see here I'm holding the container probably about three feet above my mold and it's coming down in just the finest stream into my casting and what this does is it makes the air bubbles break out of the surface of the silicon as you're pouring it so you can see bubbles in the bucket up high but once it's actually hitting the mold down there there's very few bubbles even what is done completely with this casting I didn't see any bubbles so just hold it up at a distance and pour it in there very slowly and try to maintain a nice consistent stream and so people have their own preference of how they pour their molds but I like to pour the stream off to the side of my object very slowly and let us slowly pour in and fill in all the voids and gaps this way you don't get air bubbles trapped in any holes and it really gives you a nice surface and I let this sit for about 24 hours to completely cure and then here's the bucket you can see after it's all cured I just plug the mixing stick and all the silicone that was stuck in the bucket comes out cleanly and I can reuse those for the next mold so to make our second half of the mold I'm gonna peel off these sidewalls so I can take the mold out and I'm using this foam core board and I'm going to reuse it when I do the next half of the mold so I'm trying to preserve as much of it as I can so now I need to take out my vent holes and the pour spout that I put in there and you want to make sure that you don't disturb the mold on the inside the actual cassette tape I have on the inside so I'm trying to just twist these loose and then pull them out as gingerly as I can because I'll need to flip this whole thing over for the next step and so now you want to peel off your clay layer but you want to make sure your object stays embedded into the first layer of silicone so you don't mess up the registration or anything just be very careful and peel up the clay and so here you can see that nice edge between the cassette tape and the silicone mold and you can also see those keys that we use to indent into the clay now protrude up from the surface so when we pour the next half of the silicone it'll form right over those keys and so before we do the next half I'm doing a little bit of cleanup where the clay kind of pulled out from the cassette tape and just making sure the molds clean and everything is exactly how I want before I do the next layer so I'm reusing those same foam core boards and just putting up the four walls for the next half of the mold and so depending on the silicone you're going to use you're gonna have to do some sort of mold release between the two layers of silicon because silicon will only stick to other silicone so there's a nice mold release as you can buy in aerosol forms but since this is really a one-off project I'm just gonna use this small container of Vaseline to coat the silicone but just for a one-time shot to pour the second half of the silicone I think will be fine all right now it's going to be the same steps we did for the first half of the mold you just want to mix up the components and they're separate containers because they probably have separated I think it's been like two days since I did the first half so you want to make sure you mix it real well and then just like before I'm just going to go ahead and pour the blue into the pink and mix it up so once the two parts were mixed really well might transfer him to a new container like I did in the first half I went ahead and poured the second half of the mold and again I held it up about 24 to 36 inches above the surface to make sure all those air bubbles break before they hit the surface all right so another 24 hours go by and I'm ready to go ahead and take everything apart and since it is silicone it doesn't really stick to anything so it all comes apart really easily all right here's the big reveal taking apart the two halves and seeing how it turned out and I was really happy with how the two halves came out and you know really picked up all the detail I was looking for and really worked out great and so when I take out the cassette tape here you can see there's a little bit of like flashing along the edge of the silicone where the piece linoleum was and that can just be cleaned up with an exacto blade that's just a real thin layer that flowed in between the linoleum and the clay and the key with cutting silicone is just to make sure you use a really sharp exacto blade and it just cuts through it like it's no problem I also went around the edges and cleaned up any flashing and kind of bevel the edges just so when I put it together it just fits to get a little bit nicer because these edges do get a little bit rough when you peel it all apart and my last step here is just a chamfer the edge of the pour spout that I made just so when I pour my plaster it just doesn't pour all over the place it kind of directs it more into the hole and when you use your object to make your pour spout I used a straight dowel some people make it out of clay and you can form it to have this shape there's really a million ways to do this alright let's go ahead and cast one in plaster and see how it all works so the first step is I'm going to put it on a piece of mat board put the mold together and then I made another piece of this mat board on top I just cut out to have you in the pour spout in the vent visible because basically I want to be able to tape this all together like a sandwich just to hold it so the plaster doesn't pour out between the gaps a lot of times people make this out of wood or use rubber bands to hold it all together it's really up to you how you want to do it but this is just a really quick and easy way that I'm using so I'm using these measuring containers that have markings on the side to make it easy and then for this one I'm just using just plain plaster of Paris that you get at any hardware store and I figured out the ratio I need for this particular casting and how much material I need and it's going to be about 4 ounces of material a little over half a cup of water and that'll allow me to make the casting and not have any wasted material because I'm going to be making a lot of these in the future and so like everything else people have their own way of mixing plaster up but I just add the water in and then just slowly agitate it with my hand just make sure you're wearing gloves and just get it a nice smooth consistency so there's no lumps of dry plaster left near container and it's been described lots of different ways that the texture you want you know like a thin pancake batter like you want to be able to coat your fingers when you pull it out but you'll just have to kind of get a feel for maybe do some practice runs before you do your you know your real object and also if you use colder water it takes longer for it to start to cure so you have a bit more time to mix but unlike the silicone this actually sets up fairly quick from the liquid state to where you can't really pour it any more it's kind of too gloopy so you have to work fairly quick alright so now we're all mixed up I'm going to go ahead and pour the plaster into my mold cavity if you want to just pour it slow and consistent try to avoid air bubbles as best you can but there's not a whole lot you can do when you're pouring it so I just keep pouring in the plaster until it starts to come out through the vent holes and through the pour spout and you can stop and give it a few taps as you're doing it and that will help migrate the air bubbles out of those vent holes and so now I just spent 30 seconds or a minute just capping around the mould trying to break up those air bubbles and get them to come out through those vent holes and you can kind of see the level of the plaster or as that air starts to come out of the holes all right so I figured out it takes about an hour and 15 minutes for this to be fully cured enough to take out you don't want to take it out you know after 24 hours or anything because it's gonna be really hard to break up the plaster along your pour spouts and the vent holes after that much time after about an hour so the plasters firm but easy to manipulate and clean up it's almost like a very hard clay and so here I broke off those three air vents they just pop right off but then the main spout stays on there and then I can go ahead and peel off the top half of the mold and then you can see there are some bubbles on the surface of the plaster and there is some you know fine layer of plaster seeps between the layers of silicone but you can tell that that doesn't really matter because what I care about is the other side of this which came out just perfectly smooth with not a single imperfection I'm really happy with how the surface turned out because the back side is going to be hidden anyways and so depending on your object you're gonna have to think about that when you do your casting it's really hard to get a square object to not have any kind of air bubbles in it and then here you can see the plaster is still very smooth it's just like a hard plane so I'm using clay tools and just cleaning out those seam lines and just breaking that up while it's still relatively soft and easy to do because once it fully cures after a day or so it will be much harder to do this kind of cleanup and so here's our final casting and then you can see next to the original tape and so with the exception of the square block which you'll see in the next video it's a perfect reproduction of it alright so I think that's it for the mold making part of this project so I think the casting came out really good it's going to be perfect for what I'm looking for so keep an eye out for the video where I use it and I'll see you then Thanks to keep up with the videos when they're posted make sure to subscribe to the channel and if you'd like to help support the creation of these videos you can check out the diode press patreon page thanks