Okay, what's up guys today? Today I'm out here with my mini metal foundry because we're celebrating a milestone. The video on melting Pop cans has reached over thirteen and a half million views and over one hundred thousand likes. Now when I first made the metal foundry I had no idea that so many of you would actually be making this yourselves and as a result, a lot of you have had questions and concerns and left comments about failures and mistakes that have been made and I wanted to update you through this video about some of the personal tips and tricks that I started using that may solve those problems for you. The mini metal foundry is made of some very basic materials, It's just a steel bucket with a little bit of sand, some plaster of paris and some water to create just enough of an insulating layer that you can heat up and melt metals like aluminium, brass and even silver and gold. Okay now some people would like to know why did I design the metal foundry out of sand and plaster when I could have used refractory cement, kale wool or other higher quality refractory materials like that and the answer is simple, when I designed the metal foundry I wanted it to be relatable. I wanted most people to be able to go out and buy simple commonly available materials and put together a backyard foundry that would work. Now along with that, using cheaper materials means that the system is going to break down a little bit faster. One of the most common pieces of feedback I've had from people is that after two or three firings the lid starts to crack and crumble and break and that's not just you guys that happens to me as well, but I figured out a cool little trick you can do. It'll make it last about 10 times longer and all you need is a little bit of steel wool. I went down to the hardware store and found some of the coarsest steel wool I could get and when you unravel the bundle you can see it rolls out into long strands of steel which is kind of like a metal spiderweb, and the idea is to push this down into the plaster and sand mix while it's still wet because this metal mesh will help reinforce the sand in the plaster and hold everything together about ten times longer than it would without it. If you want to get even more mileage out of your metal foundry then try using stainless steel strands instead of the steel wool. You can get stainless steel strands in things like Brillo pads which are gonna be a lot more expensive, but it should hold up a lot longer in the same kind of conditions. Another one of the benefits of the metal foundry is it's very easy to make. Over time the walls will start crumbling, but you can just bang all that crud out with a hammer and mix up a new batch, and in 20 minutes You've got yourself a brand new system. A bag of plaster and a bag of sand together will cost about $20 but the cool thing is you can make between two and three metal founders with it. Now some people wonder if you can use cement or concrete instead of plaster of Paris and I would strongly caution you not to. The reason is if there's any moisture trapped in the concrete then when it heats up there's the potential it could explode in your face. On the other hand plaster of paris and sand are very porous so they vent the gasses off and there's very very low risk of that happening at all. Now the foundry will reach temperatures up around 2,000 degrees Fahrenheit, and I know that because of a melt copper and if it can melt copper It'll melt silver and gold as well. But it probably won't melt steel. Steel has a melting point up around 2300 to 2400 degrees Fahrenheit so you might be able to use the metal foundry to help you forge steel, but you're not going to be able to melt it down and cast with it. Okay let's talk about Crucibles. Now I used a fire extinguisher for my crucible and that was mainly just to show that it could be done in an apocalyptic situation. I certainly wasn't recommending that a fire extinguisher was the best way to go. But it's blowing my mind how many comments and questions I got from people asking where to get fire extinguishers, or that they bought a fire extinguisher only to find out that it melted in the foundry, so let's address that issue first. First of all if your fire extinguisher is melting in the foundry, it's NOT made of steel. Remember a magnet will stick to steel, but it won't stick to aluminum so if you want to know if your fire extinguisher is made of steel or aluminum, touch a magnet on to the edge and see if it sticks. I got my news from an industrial equipment supplier but that's not going to be the typical story for you. By Far by Far by Far by far the best crucible I've ever used is called a clay graphite crucible, and it's one that I found off the internet for about 30 to 40 dollars, Now it seems like a little bit of investment, but trust me a fire extinguisher isn't gonna be any cheaper, and the clay graphite crucible is Gonna last a lot longer. I've personally put mine through over 30 different firings and it has taken a lot of abuse, you see it's vitrified and almost like turned to glass on the edges but I put this thing through thermal shock. I heat it up, I cool it down, I heat it up I cool it down, I heat it up and cool It down again, and it just keeps going and going. I even cracked the side of it once but it seemed to just heal itself, so a clay graphite crucible is probably what you want to go for and I'll put a link in the description to one I found on Amazon that I think would be a good recommendation for you. Now when it comes to making ingots I've made all kinds of different shapes sizes and styles but definitely by far my favourite are the mini metal muffins, these ones are my very favorite because they're extremely easy to store They're very easy to melt and they'll almost fit any sized crucible, if you make some of the bigger muffins you're getting a much bigger crucible to melt them back down, and it's gonna take a lot longer to do now Let's talk about charcoal, not all charcoals are created equal, the charcoal I used for my first firings was the kingsford charcoal Which is used for barbecuing there are ingredients in there like lime Which is specifically designed to make the coals burn lower temperature? So they last longer, so if you ever switch over to something like lump charcoal which is basically just [pyrolized] wood You're gonna find a massive difference in the way it operates. The first thing I noticed about lump charcoal is it emits a shower of sparks, so you definitely want to make sure you're wearing long sleeves or you're gonna end up with little sparks burning your arms. The other thing is it burns a lot hotter in the early days I had one of my steel fire extinguisher crucibles in there And it actually got so hot that it melted the steel and all the aluminum leaked out So if you use lump charcoal it will burn a lot hotter, it's very very powerful stuff But you need to watch it more carefully, use a lower setting on your hairdryer You don't need to be pumping that much air into it to get the same temperatures If you're still using Charcoal to melt your metals and as soon as you turn the hairdryer off pull the tube out of the metal foundry. If you leave the tube in the foundry with no air blowing the heats going to travel up that too and melt your hairdryer And you're gonna end up having to get a new one. Now if you made the switch to the propane conversion congratulations I hope it's working well for you But there are some things that you should know like if you run the propane tank for more than about 25 minutes It's going to start getting really really cold it may start to sound like the gas is running out But really what's happening is your propane cylinder is starting to freeze up, a couple of ways you can battle that is to get a big bucket of warm water and just dump your propane tank down into it to help warm it back up again, or just get a bigger propane tank they'll take longer to freeze. Now I want to talk for a second about styrofoam casting. I did styrofoam casting in my previous tutorials because I think that's the simplest method to get started in casting But it doesn't always yield the cleanest results. It's a trial and error sometimes it works sometimes it doesn't. It blows me away that this concept even works at all that you can just bury styrofoam in sand poured Molten Metal and Pull out a casting that looks almost identical But the surface is going to be rough and sometimes the sand collapses and you lose your entire project. Another thing you need to consider when styrofoam casting is that styrofoam can bend, so when you're adding your model to a bucket of sand you need to be very careful about how you add the sand, because putting too much pressure on it can bend the mold and then when you cast it it's going to come out looking funny. Now if you want to pull the most value in the most detail from your Styrofoam castings as possible it does make a difference what kind of sand you use. Regular play sound will work great but if you want even more detail you can go to the pet store and get aquarium sand which is extremely extremely fine sand. That'll just be able to get into all the nooks and crannies a lot better and help your casting come out looking really crisp I worked with very very wet sand all the way to extremely dry sand And I haven't noticed much of a difference between them Some people wonder how long should they let their foundry cure before they use it and honestly I don't really think it matters. I use mine the same day I make it and it seems to work just fine. One other disadvantage to styrofoam casting is as you pour, quite often sand will fall into that molten mix which will contaminate the purity of your metal so even if you try and buff it up Sanding it and spend a lot of time You're gonna know as little specks of sand start to surface through and you'll never be able to get a perfectly smooth finish Now if you really want to get serious about sand casting rather than using styrofoam which vaporizes every time you pour your metal, look into green sand casting instead It's about 90% sand 5 to 10% clay and then just a little bit of moisture to get it to a consistency where it'll hold together like a sandcastle. The cool thing about green sand casting is you only have to make your model once and Then you can pack the sand down around it and then pull your model back out you can reuse your model in your sand over and over and over again now a lot of people ask me to try casting the foam fighter jets from a previous project, but there is a problem and that's that the foam is not thick enough for the molten metal to get down inside. I've noticed with dollar-store foam board your object needs to be about two to three layers thick in order to get the Molten metal into all the crevices. If it's less than two thick your chances are very very low that it's going to fill all the gaps Now let's talk about spalling. At certain times of the year there's probably moisture held within the concrete and if you ever spill your molten metal on the concrete, it can flash that moisture into steam in an instant and explode spalling out bits of concrete all over the place. Now in my experience these chunks of concrete fly up to about 5 feet away which doesn't sound like much, but remember it's spewing molten metal at the same time so if you're working over concrete be very very careful that you don't spill any molten metal. If you want to be extra cautious then do it in an area that's covered in sand. When I was making the mini master sword I failed over and over and over again Metal casting is an art form it takes a lot of practice. You're not going to get it right on the first try It's just a lot of fun to get in there get your hands dirty See, what works and see what doesn't play around at the materials that you've got and see what you can create So there you have it guys I actually am still a really big fan of the mini metal foundry after two years of using it I still use that one personally, and I haven't made another system because it gets the job done and it works so well and remember that this is an entry level system If you want to get really serious about backyard casting, I'd strongly recommend looking into proper refractory materials. You want to be getting a refractory cement or kale wool. It's expensive, but it's really good stuff and it'll last a lot longer. The purpose of this project was to get you thinking outside of the box and seeing that you could do things on your own, and there are other ways to do it as well my friend Nighthawk and Light just dug a hole in the ground and blew some air into it and that was enough to melt aluminum the backyard scientist just put out a tutorial for making one of the simplest propane burners I've ever seen also check out the art of weapons This is a kid who took refractory brick and made his own electric kiln for melting metals as well which is very clean and uses electricity instead of propane or charcoal. So there you have it guys. There's a few tips and tricks that hopefully will help you and your backyard metal casting experiences Thanks so much for supporting, sharing and liking these videos that I can keep making them and I'll see you the next video Talk to you then
Was seriously thinking about using these videos to build my own this summer. He has several videos on his channel that would be really useful. Kevin Kelly, cofounder of WIRED magazine, just recommended this channel on his weekly email along with Mark Fruenfelder of BoingBoing.net. Another YouTuber (Cody's Lab) also has a bunch of fascinating chemistry and metal refinery videos. Grant is in Utah (just down the way from me, actually), and I think Cody might be too.
I made one of these. I can't figure out how to quickly/safely refuel it. I can get it going quite easily, but once my initial charcoal burns up I have a hard time getting new charcoal in the right position so the crucible still fits inside.
I'm considering converting it to propane just to eliminate my charcoal problem altogether.