Antiques & The Arts
Can You Melt Obsidian and Cast a Sword?

Can You Melt Obsidian and Cast a Sword?

Over the past few months I’ve been working on this video as a follow-up to user comments on a previous video on if it’s possible to cast obsidian. This proved to be a major challenge that took six attempts, broke multiple crucibles and two different kilns. But I didn’t want to stop until I finally had success at casting obsidian. Previously I made obsidian blade by knapping, which is kind of a Stone Age technology. But a lot of people wanted to see me try and do actual casting with obsidian. Which is something that’s pretty difficult because actual obsidian doesn’t melt until over 2,000 degrees Fahrenheit Which is something that’s very hard to achieve. So while looking for this I realized that you can actually cast glass using sand and a similar method that I used for the aluminum But because I can’t melt the actual obsidian, I need to grind it up into small little particles, mix it with the flux and then melt it. And hopefully then I can cast it into some form of knife Obsidian is largely made of silica like regular glass but also has an unknown mixture of other impurities in it as well. That can make its melting point difficult to work with. Melting straight obsidian is potentially possible But would likely result in a very thick viscous substance That’d be hard to work with especially to cast my early attempts at glass making also had a fair amount of impurities which made it really difficult to work with so The solution to this is flux Which is adding chemicals with lower melting points that make the entire solution melt easier and be fluid enough to cast so the thing with knapping is that when you fracture it you’re able to create potentially razor thin blades that are a Molecule thick you. Can’t quite reach the same sharpness by just sharpening glass itself But you should be able get something close and it’s also probably gonna be pretty Brittle as even this is brittle itself and it has wood reinforcing and holding it So let’s give it a shot. First up is grinding the obsidian, melting it down and see if this is even feasible I used a ball mill to grind it to a fine powder in a liquid solution, which I then need to boil off. One of the biggest pains is getting a crucible That’s just big enough to hold a large enough volume, but still fits inside the rather small kiln As it heats the Obsidian and flux tend to boil over some and unfortunately in these smaller crucibles nearly everything spilled out For this first test it looked like the Obsidian and flux may have separated, which means this might not be feasible Also enough spilled out and burned through the insulation until it broke the kiln’s coil making the kiln unusable Next I tried a larger batch using a more flexibly designed kiln that I could scale up to fit a larger crucible (whispered) I uh, suck at this It’s melted all the way through. For an initial small test knife I carved a model out of styrofoam and then packed it into the sand Once poured the hot glass will burn off the styrofoam and fill in its place Like regular glass, if my cast obsidian cools too rapidly it’ll fracture and shatter So I took a note from the compound we used when we made glass with Grant last year and picked up a bag of vermiculite. Which can act as an insulator to allow the glass to slowly cool Alright, lets give this a shot. Unfortunately that wasn’t enough and it still ended up shattering But the most interesting result was that the remelted obsidian turned out fairly transparent with just a slight amber color This is likely due to the flux which probably added to the transparency But this also might be related to how this glass is formed versus the original obsidian Which raises an interesting question on if this compound could even be considered obsidian anymore Regrinding this glass, I started a new batch, but this time, assuming it got more clear because of the flux I thought I’d attempt to counteract it by adding some new impurities back in specifically added in some metals that are often used in glass making to dye glass black: nickel and chromium Which gave it a nice dark color very similar to what it started with Now to cast it. (talking about fluffy cat) Usually she just lays in the grass and eats it. So I’m gonna try and cast this toy Roman sword in obsidian but I don’t want the handle to be obsidian So I’m gonna cut that off Unfortunately by the time it came to pour it, my crucible had cracked and the majority of the obsidian had leaked out While I reset again for another attempt I was curious to do another experiment to see what would happen If you try to melt just straight rocks of obsidian This resulted in a interesting formation of a foamy mess Likely caused by off-gassing of compounds like water that’d previously been trapped in the obsidian The semi molten obsidian adhered to the crucibles as well as the sides of the kiln which unfortunately caused this kiln to break as well But in the interim I had fixed the first kiln and gotten a better fitting crucible. So let’s keep going Collecting as much of the previous attempt as I could Plus adding some more crushed obsidian And some more flux I’m ready to go again This time with a very promising pour Alright, moment of truth to see if the sword is in one piece I’ve had mixed results so far with the vermiculite of Some things still shattering in it, some things not Let’s see what we got Dreams shattered dreams Refusing to give up I brought my setup to glassmaking studio FOCI Where I could throw my final result into their annealing chamber and not risk it shattering Okay, so got a weird reaction in the last attempt where it got really bubbly when we poured it not sure exactly why, there might’ve been some cracks that formed when I transferred the mold or There might have just been more humidity in the air that made it damp and caused a reaction I’d like to polish this, it’d probably break up if I try to grind it and shine it up. So We’re gonna go over there. Give a one more shot to do it the right way previously I added a little bit of a tang to attach a handle to it easier But that’s kind of flimsy so I’m a little worried how well that’ll hold up. So I think I’m just gonna do the whole thing obsidian, So I’m just super gluing the handle back on sand cast it once more I hopefully will finally have the obsidian sword Not very strong Working with FOCI, I learned how sand casting for glass is done a slightly different way Instead of packing the sand tightly around the mold you lightly place the mold into the sand and pack it only along the edge The idea is to allow the air to escape through the sand so it doesn’t bubble up through the glass like it did last time Then they also torch the sand to leave a fine layer of carbon on top. So the glass can better release from it So after six attempts, I finally managed to cast a full obsidian blade. Unfortunately in the annealing process it got a little cracked and Probably can’t polish it off and put a nice edge on it, unfortunately I took quite a bit of flux in order to make it cast-able which made it a bit difficult to actually temper It’s kind of messed up the whole annealing and made it a bit weaker, so it’s more ceremonial at this point. despite all the mythology around obsidian, it’s really fragile, just glass and uh… So put it through a whole different process than how the obsidian originally formed, which is evident when it became pretty transparent at one point and then I had to add the additional dyes in order to turn it back into black. So it’s kind of debatable if this is obsidian, but it’s definitely made from obsidian and uh, took a lot of attempts, though I finally made it So this took six attempts and broke two crucibles and two kilns. Just fixed this guy and last time this crucible cracked it leaked the obsidian all over it and Eroded and did a ton of damage Fortunately, it’s still working at this point But I don’t want to push my luck too much so as much as I enjoy making unprofitable videos and I’m gonna call it at this point say it’s complete So now that I’ve cast the glass next I’m gonna move on to a different mineral, actually try and do actual metals with some copper and make bronze So I’ll do that in uh… In a while If you enjoyed this video be sure to subscribe and check out other content we have, covering a wide variety of topics Also, if you enjoyed these series consider supporting us on Patreon We are largely a fan funded channel and depend on the support of our viewers in order to keep our series going Thanks for watching

100 comments on “Can You Melt Obsidian and Cast a Sword?

  1. the major problem was that you were remelting the same obsidian each time which kept getting more contaminated and weak.

  2. So, he made a portal to the nether in his hands. Why didnt he go through it so he could make a nether rack sword?

  3. Kinda makes you wonder how natives managed to turn obsidion into weapons. Though I'm sure it's a much more simple process then trying to melt it down and smoothly form it.

  4. 0:40 once I saw that my brain went "so he's making a Minecraft mod in real life wow that's pretty cool" edit:wow I didn't realize how many Minecraft comments there were:/

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