HOW TO CAST HYDROSTONE PLASTER into a Mold / Mould Tips & Techniques

Hey everybody, John Burns with John Burns Fine Art. Please like the video that helps me out a lot and if you're interested in seeing more videos like these please subscribe so you can stay up to date with all the videos I'm making and make sure you hit the bell button and select all notifications and you can always turn that off if it gets to be too much but in the meantime you know it's good to see what's coming. Also if you're just watching this on YouTube and you don't have an account set up, set it up. It's so easy. It's free. It's wonderful. You can subscribe to wonderful channels like mine and others that you find interesting. Also if you are interested in knowing any of the products that I use to do anything like this, check out the description. It'll take you over to Amazon. I have an Amazon affiliate account set up so that I can create the links down below and it will take you right there. It may or may not open up the app in your phone but if you select any of the items and they go into your cart they should stay there until you get back to your app. So I appreciate that and I appreciate you. You guys are great. So as a follow-up for my video of making the mold, I just wanted to start out and talk about casting. Some of the hang-ups that I experience and some of the things I've learned. Well trapdoor is the number one problem with making casting so I'm hoping that these tips help you out. Although I'm not using this mold in particular. This is a simple bas relief, low relief. This is just a silicone block mold. You can pour it in, pop it out but no matter how much you try, I mean you can try to blow around if you want with your breath or if you get a little older and your lungs aren't quite doing it you can use a straw. So there is another way and I'll do a little plug here for a channel called Plaster Master. I'll list it down in the description. This guy doesn't get as much attention as he probably should. He's really good at working with plaster. I haven't watched a lot of his videos but from what I have seen he knows his stuff. So he talked about something that's called a surfactant and you know it's the, let me see if you can see it there. Windex is essentially all it is. You cut it 50-50 water and then 50 windex and what that does is actually displaces the water that is in the plaster. Just give it a simple coat like you know maybe two so it's just misted. What ends up happening is when you pour in your plaster all of a sudden that water tension or the table like if you put a droplet of water on glass you can see it kind of sitting there in like a droplet. Well when you spray something like windex that water displaces it can't hold its shape. So that actually forces all the air out. You begin to move the density of the water to the bottom instead of from the top and it pushes any trapped air out. It's an awesome tip and it usually does a pretty good job. The reason why you want to cut it 50-50 is because you don't want it to mess with the plaster. You do too much windex it can start to make the surface not quite so hard. It might even make it a little chalky if you go too extreme. So there's that tip and the problem with something like block molds here, this is from a previous video I did, the block mold is that you would have to spray it, spray it and then you know cross your fingers and hope that it all goes well. Well I can't remember that maybe I did that and then closed it up and then I put some bands around it to hold it. By the time I actually got into pouring it wasn't enough really. There's still some little pock marks from the air and I couldn't really turn this. Like if I would have been smart about it I could have probably put my hand or something of that nature and just kind of turned it up to let those air bubble, the trap sections here, let that air out and let plaster roll in and then maybe roll it in such a way that the air couldn't come back into it and then you know you set it to the side and let it kick and then tap it and let the air bubbles rise up. You know keep doing it until the air bubbles just start to look very small on top and you should be okay. If not try again. So with that one I also had a companion mold of the foot and you can see here a lot of air bubbles there, air bubbles in the toenails. But again if I had like maybe used that surfactant and then poured that same day I ended up getting distracted and I had it taped up or banded and I didn't want to undo all that. So you know laziness, bread, flawed work. But I'm sure that could have been easily fixed too if I would have just rotated it a couple of times. And I am building a rotational casting machine for smaller molds like this that would be very favorable because then I could just put a you know a plug or a cover on that and then just roll these things and they should come out pretty spot on. I've been in stores where you see plaster castings and usually right on the top of the head you'll see a bunch of air bubbles. So like right here this is a sculpture by Deleux, Jules Deleux, French artist, 19th century. His buddy was Rodin. They were friends. He was a student of Jean-Baptiste Carpeaux but unfortunate enough to have a plaster casting here. And I actually was, I cast this. It's not that I just got it but I got this uh my hands on the mold and I did a casting and this one turned out virtually flawless. I don't think there's anywhere but maybe one little air bubble trap down here. It's a little pen bubble and if I really wanted to be slick I could shove something in there and no one would be the wiser. Oh there's another one. So but otherwise on the features it's flawless and what I did to do that was when I put the plaster in it I put a board on the bottom and it wasn't completely full but I had rotated it and I kept rotating it. So I was tumbling it. I'll just lay this down so hopefully we can see that. I was tumbling it this way and then I would tumble it that way and I tumble it this way and tumble it that way. And the thing about hydrostone when you're casting it is the more you keep it in movement it tends to last longer. Its pot life lasts longer. If you let it sit it will kick a lot sooner but I didn't know when that was going to be and I have in the past turned these things by hand. It took about a half hour. I was literally sitting in a chair turning this in my hands for a half hour and it gets exhausting but I knew the importance of this artist and I wanted a very beautiful piece so I did it. But there's been times when I have stopped prematurely because I thought this is really taking forever and so this is from one of my molds. I busted off some of the other pieces. It was a scrap casting but you can see here where it's hollow this is the wall around here and it got as thin as you know an eighth of an inch three sixteenths of an inch and it comes back around to you know we're looking at like five eighths and some of the thicker parts but what had happened with this one was I was turning it turning it you know turning it and this one is like cylindrical so turning it this way was a real pain turning it this way not so bad but there's at one point I told myself you know if I stop it's going to kick at that that one moment but I decided you know not really I'm just going to stop for a minute and let this stuff really start to set. Well as soon as I did that I don't know it was just like that thing in your head where you say that wasn't a good idea and I started to turn it again and it had already started to set so it started to set like right when I stopped so that was not good and there's like air bubbles here you can kind of tell that was trapped air because it's nice and smooth that's not chipped out it's actually smooth so that was a bubble and there was just massive spots where there was like no plaster at all where it had rolled away and this being a silicone mold if you're not keeping that stuff moving it will you know just fall off the sides you have to keep it moving until it starts to set up to where you're turning it faster than it can come down and this one here I just stopped and started to roll off that silicone because materials usually don't stick to silicone so that was a boo-boo so for the so this is the mold from the last video this is the two children who are sitting there sleeping I drilled a hole in the bottom of this so I took a measurement from the top diameter and then the bottom diameter and I have somewhere in the middle here so I drilled that smoothed it tried to make it so that I could get a better seal on it if you use Vaseline on this to try to use like some kind of seal it will just you know come right out but I wanted to put this in my rotational casting machine but it is a hair too big so now this one I can either do it by hand or I can pour it in and try to methodically eliminate the trapped air or make it so that the trapped air shows up on the back side which is going to be on the wall because it's part of my clock project so anyway this is I'll have to anyway so that's where we're at I hope some of these tips in the beginning are good for you if you want to see me cast that clock sculpture I'll talk a little more about it before I do it and I can even show how I mix up the plaster and we'll go from there so stay tuned like and subscribe this video please if this was helpful and of course the subscription click all notifications that way you can stay up to date with all my projects and learn something for yourself this is free education so drink it up no seriously you guys there is greatness inside you and with the passion to create you can do wonderful things and create wonderful things that you're proud of and share your creations with the world I mean it I truly do and stay inspired you guys take care stick around