2-Part Silicone Mold using Mold Star™ 16 FAST

hello welcome to my step-by-step tutorial on how i made this two-part mold let's get started so today my model is this cute little glass bear that i found at a local antique shop i thought it would be a great model to replicate because it's small in size and it's not too complicated although it does have some undercuts so it will require a two-part mold now to get started on a two-part mold you have to decide where your parting line is going to be where your first side and your second side of your mold will be basically on this model it's pretty easy to determine because i can already see a line in the model so i'm just going to follow that natural line so to begin i'm using some sculptex sulfur free clay it's important to use sulfur free clay because most silicones will be inhibited by anything containing sulfur so what i'm doing to begin is embedding my model in this clay i'm going to build up to that partition line that i showed you in the beginning and i'm just going to slowly add pieces of course now i have the video running at hyperspeed because i actually work very slowly and we would be here for hours so now what you're going to see me do is add a little bit more clay to build out the sides of my walls here and that's because you need enough room to make your keys which i'll be doing next so i'm just building it out so i have a nice even border all around my model and here it is all smoothed out i've carefully cleaned that parting line that goes around the model i've cleaned up the clay everything is good to go for the next step so to make my keys i am going to use this bolt it's a nice handy item i already have around the house i'm just going to be pressing it into the clay to make an indentation the purpose of making keys in your two-part mold is so that your side one and side two lock in together it helps them register perfectly so that you have a nice seamless casting because i have a small model i don't need to add many keys i'm going to put them around as many as i can being careful not to disturb the clay around the model now i've ran out of room to make additional keys with my bolt so i'm just using a pencil eraser to just add a couple more keys so in this next step i'm cleaning up my model this is an easy step to forget but you know in the process of embedding it in clay it may have some residue some fingerprints you just want to clean that up with a little bit of alcohol now we are ready to begin to build our mold box here i'm carefully laying out my mold box walls i want to make sure that they're cut to the right size and i have a plan in place of how i'm going to glue them down for this project i'm using quarter inch foam core board i just had some extra laying around the house it's the same stuff that you buy from any craft store to begin gluing them down i'm using a hot glue gun as i move around the model gluing my walls in place i want to make sure that i'm avoiding any voids between the clay and those walls you will see that i begin adding pieces of clay in any gaps just to fill that void prevent any silicone from leaking down the next step here is to really reinforce all your seams with more hot glue so i'm going around the bottoms the edges sealing up any little nooks and crannies the silicone will leak out of even the tiniest of pinholes so go around a couple times if you have to now i'm going to be measuring my mold box i have the dimensions of my model and my mold box so i can determine how much silicone i will need to dispense i like to use the online calculator found on the smooth on website where i can plug in the dimensions and it tells me the total amount that i need the material that i'm using for this project is mold start 16 fast now i'm going to show you the lid here in a second because it is very important to pre-mix and stir each the side a and b before you get started now i'm ready to move on to dispensing my silicone and mixing it up so conveniently the amount that i need will fill this plastic cup to the top so i'm just going to go ahead and put the part a into the cup let it fill up to the top of the rim i should also note the mix ratio on the mold star 16 fast is 1a to 1b by volume this means that i do not need a scale to measure it out it's super easy to just do the 1a to 1b visually in equal parts okay now that i have those dispensed i am ready to mix at this point i am setting a clock because i'm working with the fast formula once the part b goes into the part a your clock is ticking the pot life is six minutes this is the working time i have before the silicone will start to solidify so i'm keeping an eye on the clock i'm double mixing my material into a new container scraping the sides scraping the bottom mixing until it becomes a consistent color at this point i'm ready to pour here i am pouring the silicone into the lowest part of my mold box i'm allowing the silicone to seek its own level up and around my model i do this very slowly but i have it sped up just for the sake of demonstration purposes now i'm going to allow the silicone to fully cure which on the moldstar 16 fast is a full 30 minutes once your material is cured you can begin to take apart your mold box i'm just gently prying the walls off of the silicone and the clay trying not to disturb the clay and i'll just remove them all i'm going to quickly clean off the board the next step would be to remove the clay the next step of course would be to be putting our mold walls up again again i'm also cleaning my model of any clay residue that may have been left behind and i'm just using a little isopropyl alcohol to do this now i'm ready to assemble my mold box around the first half of my silicone okay that's looking great the next step is to coat your mold rubber with release spray this is a very important step i'm using the ease release 200 you're also going to want to do this in a well ventilated area now i've got my second batch of silicone already mixed up and i'm ready to pour the second side of my mold i'm going to follow the same process by pouring into the lowest part of the mold box and allowing the silicone to seek its own level i also want to note that one of the reasons i like the mold star line is that it does not require vacuum degassing it's a low viscosity which means that it flows pretty easily and it's not likely to entrap bubbles or air into your silicone now that i've filled up the second side i'm going to wait that 30 minute cure time again now that the silicone has cured i can pop off those mold box walls great now we're done and we just have to peel apart the two sides of our mold there's a little bit of overlapping silicone but if you apply some gentle pressure it will peel apart easily and that's it i can pop my model out of the mold you can see perfect detail is replicated on both sides of the mold i can just assemble each side locks in together perfectly and i'm ready to move on to castings for this project i'll be using smooth cast 326 and so strong colorant as always i'm going to thoroughly pre-mix the material by shaking the part a and b thoroughly next i'm going to prepare my mold i'm taking a few pieces of rigid foam core and rubber banding them to either side of the mold this will give it even pressure all around and prevent it from leaking at this point i'm ready to dispense my material smooth cast 326 can be mixed by measuring one part a to one part b by volume these equal parts by volume make it super easy to dispense and measure accurately for my first casting i'm going to be using the so strong red colorant i just show a little bit there on my stick a little bit goes a long way i'm stirring it into the part b to achieve the color i want before i mix them together all right we are now ready to mix i'm going to pour the part a into a new clean container making sure to scrape the sides and bottom and get as much of that material out of the cup as possible and then i will repeat the process with the part b and begin mixing them together oh but before i do that i'm just going to grab my phone and set a timer i like to set a timer when working with materials so i can keep track of the pot life the pot life on the smooth cast 326 is seven to nine minutes this is the working time you have before the material starts to set up and you can see here i've mixed the material and then i double mixed it by pouring it into a second clean container now i'm going to pour it into my mold and i'm pouring just a little bit at a time to coat some of the undercuts since i did not add any vents and then i'm going to fill the rest of my mold up and pour the excess in a cup on the side and thumbs up because i finished within my pot life an hour later i can see the material and my cup is cured so i know that i'm safe to de-mold my casting the mold easily splits apart and i can pull out my first casting and it was a success thank you for watching my process on how to make a two-part mold in castings and i hope it helps you in your own projects going forward good luck

Channel: Smooth-On Fan Channel: Made By You

Views: 221,196

Keywords: somadebyyou, madebyyou, demonstration, tutorial, how-to, smooth-on, smoothon, mold making, mold max 30, mold star 15 slow, smooth cast 300, resin, rubber, silicone, urethane

Id: kuIqpiQ1000

Length: 14min 24sec (864 seconds)

Published: Fri Jan 22 2021