Argh. Why Is Copper So Difficult?

Argh. Why Is Copper So Difficult?


Hey guys, welcome back to another day of backyard metal melting. In yesterday’s video, I tried using green sand casting and some styrofoam to create a custom copper gear. The problem is, it didn’t turn out as perfectly as I wanted it to, and I think that’s because copper has a really high melting point which means it cools down a little bit too quickly. So for this video I wanted to re-visit that experiment because my OCD is kicking in and I want to get one of these things near perfect. Now I just took my copper gear that I’m not extremely proud of and I cut it in half so that we can re-melt it and I also made a trip down to the hardware store and got another $30 of copper tubing and this time we just cut it and smashed it flat so we can cram more of it in the crucible. So believe it or not, this little bit of metal here, you’re looking at about $60 of copper. I also have a little copper nugget left over from the casting we did yesterday, so I’m going to throw that back in, load this crucible up with copper, and then prep our sand casting mould for another round. Okay, we’re going to stick this in and light it off. So update guys, we just got our styrofoam gear set back in the box, we’ve got our green sand packed in nice and tight and we are ready to cast once again. Now I think one of the problems we were having yesterday when we were pouring the copper is we waited too long to get it into the mould. One very interesting observation we saw was that as we got the crucible close to the styrofoam, it melted, just from the radiant heat, and that was very cool, but the solidifying point of copper is very, very high, so even just having the crucible out for 35-40 seconds, I think made so much of a difference that it wasn’t quite as liquid as we needed it to be. So when we try pouring our copper this time, I’m going to try it in two stages. On the first pass, I’m going to take the crucible out and use the heat to melt down the styrofoam and then place the crucible back in the foundry. I’m going to let it heat up for about another 5-10 minutes so it’s ripping hot then we’re going to pull the crucible back out and pour the copper immediately before it has any chance to cool down, and see if we get any better results with that method. It’s nice and toasty – you can see it hasn’t quite melted yet. That’s okay. Because we don’t need it molten yet. We’re just going to use this to melt the styrofoam. All right, now I’m just going to use the heat from the crucible… Look at that. So cool. Uh oh. I think my crucible touched the top of the sand. Oh no, it did! Okay, so that was kind of a bummer guys. I got the crucible too close and I actually made contact with the sand, which crushed it and kind of ruined my mould so I’m going to have to use my other styrofoam gear, and make another one. It’s kind of cool though, look at that. Just makes like a styrofoam shell. Solid on this side, shell on this side. That’s kind of interesting. All right, another fail. You can see that copper hasn’t melted yet, but that’s okay because we’re just going to use that radiant heat to burn out the styrofoam. Here we go. Oh that’s beautiful. That looks really cool. Note to self: Don’t get too close! [laughter] Right, we’ll put this thing back in. Looking nice and molten there in the bottom. All right, I think that’s good enough. I’m tempted to try and pull the styrofoam out but pretty sure I’m going to wreck the mould if I do, so I’m just going to leave that last layer on there, fire the copper up until it’s ripping hot, and then pour it right in the centre and let it flow out. We’ll see if that works any better. Fingers crossed! In the mean time, we’ll cover it up to keep it clean. Update guys, I think our copper is just about ready. It’s been sitting in the foundry for over 20 minutes and it looks really, really hot. Our mould is prepped and ready to go, so let’s go ahead and turn off the foundry and see just how quickly we can actually make the transfer. All right, time is our enemy. That looks ripping hot, holy heck. I’m going to bring this out here, and, give it a pour. Here we go. Wow. That’s a lot of copper, but look it just – oh man – it just popped out that chunk of sand. The sand just came out, that’s really discouraging. What is up with this guys? What is up with this? Look, it didn’t even complete there either. And this thing is already cooled down; well, maybe not! I could still break that and chunk it. Pour that back in the foundry then. Okay, failing all over the place. Why cannot we get this to work? Well, I guess we just make another one! So I have to admit, at this point I’m a little bit lost – burning out the mould didn’t seem to make a difference. If anything, it kind of let the sand go and the sand floated to the top. So at this point I’ve just gone ahead and made a new styrofoam gear. We’re going to take the copper out, pour it as fast as we can and hope for the best. Here we go. Ooh, that looks toasty. All right, quickly, quickly. That look a little more – awww haw haw haw haw That was definitely more molten, but look, another one of our little sand pieces came out. I wonder if that’s because our green sand isn’t quite stable enough? That is very, very frustrating – I’m getting very upset about that. Everything about that was beautiful except this little chunk came out. [laughter] That looks pretty cool though, huh? Oh, that was almost perfect! So close! So here we are guys, I went ahead and made another one. I think technically this is our sixth foam gear we’ve tried casting. I did something a little bit different this time: I wet the sand down a little bit more. I’m thinking part of the problem we were having earlier is maybe the sand was little bit too dry, and that’s why it was flaking out, so I added a bit more moisture. So now this thing’s set, we’ve got a new batch of copper melted, so we’re going to give it a pour, and just hold our breath and hope it works. If it doesn’t, I think we’re just going to go with whatever we get, because I’m not doing that again. Let’s rock! This is our last chance, so it’d better work. All right, here it goes… Oh… See those chunks of sand still popping out? There it goes: all three of them popped out! No way! The rest of the gear shape filled up pretty nicely though. Just take these chunks of sand out… That is so bizarre. Well, that looks a little more molten this time. Our copper was hot enough to even out. The only problem was, the little impressions of our sand popped out as well. Dang it! Oh well, I’m going with it. I got a copper gear, I’m keeping it. We’re calling it good. That’s hardened up quite a bit. Sure does get crispy. Crispy sand. Let’s see how well that held its shape. Oh, it actually looks pretty decent on that side. I like it! Oh look, it’s actually got the little radioactive indentations there. Looks like it cooled down a little bit, before it popped off. Oh look at that! Obviously it’s still hot. Let’s go ahead and quench it in a bucket of water. [sizzling] [scraping] Well guys, I feel like that took way, way longer than I ever wanted it to take, and after 6 attempts here I’m starting to lose confidence that casting copper in green sand is even a viable idea at all. I’ve never actually seen anybody else do it, and that’s why I wanted to try it for myself, but it seems the two problems we keep running into is either the copper cools down too quickly to form a nice mould, or it destroys the sand and breaks up all the details. In either case it was worth a shot and we learned something about the process and now I’ve got a $60 copper paperweight I can go throw on my shelf. If you’ve ever tried green sand casting with copper and had success with intricate moulds, leave your comments down below – I’d love to connect with you and see how to get this to work. Until the next video, thanks for joining me for this experiment guys, I’ll be looking for you in the next one. Talk to you then. Just a random thought here: we could probably drill these pieces out and clean out with a file. That might work. Oops, that’s still hot. Don’t put your crucible in water. Hey guys, thanks for watching, and remember I’m giving away prizes now on every new video. All you have to do to qualify is subscribe to my channel, ring the bell, and select to be notified when my next videos get released. The secret link to my giveaways will be pinned in the comments for the first 12 hours. If you like what I’m doing, show your support right now by giving this video a big thumbs up, and share with a friend. I love you back, and I’ll see you next time.

100 Comments

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  2. 1. Use liquid nitrogen to freeze sand and remove Styrofoam and then pore copper into it
    2. Use concrete and Styrofoam
    3. Use clay and styrofoam(if need use liquid nitrogen)

  3. The gear is probably coming out all bumpy from the moisture explosively evaporating from the heat. Maybe wet the sand with something else or make some kind of cast that's easy to break away and that you can preheat so the copper doesn't drain its heat so rapidly.

  4. Over the video it didn't seem all that hot until he quenched it in the water. Then I remembered just how hot it still was.

  5. just a thought, i used to work in the art department of a foundry that produced brass belt buckles, the sand they used was mixed with regular, new motor oil. They were able to achieve fairly fine detail. Their process was very similar to what you are doing. they had hydraulic tampers instead of wood blocks. Each casting was pressed from a reusable Zinc master. They reused their sand after sieving it for chunks.They always faced with new sand. Since was not in the foundry section, i can only offer what i observed. keep up the great videos, i enjoy they immensely.

  6. I believe you should retry this experiment with different sand or temperature. The reason i think your attempts to make the gear casting is because you needed a second layer of sand on to so the cast wont have air pockets but you need a funnel that leads to the center of the gear

  7. You could try skimming the molten liquid to remove impurities and you could try tubing the styrofoam and building a much more stronger mold around it of clay, Cement or POP. Idk just suggesting

  8. Just pour the copper onto the foam. It’ll melt the foam and fill all the space with copper. Or leave legs on the foam and cover the tire thing with sand then pour the copper onto the leg and it’ll fill the mold easier

  9. Hi, why don’t you mix some molass like the ancient were doing to cast iron. They were making a mold from sand mixed with molass and then put it in a oven to melt the styro and at the same time cook the molass to make the sand rock hard

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