Hey guys, I'm Nate.
Welcome back to the workshop where today We're gonna be trying once again to make our copper radioactive gear This is something that has been tried a couple of times before on the channel to mixed results so today we're gonna try adding a couple of new techniques to see if we can finally get a nice clean pour of our gear We've got our styro-slicer' some pink rigid insulation foam and our gear shaped template So let's see if we can cut out a new gear and try and get that to cast first Let's cut one of our gears out of our template The paper doesn't get cut by the wire the wire isn't hot enough to burn its way through Which lets the paper act as a guide as I go around the foam it won't cut through the paper So I can just push it right up against there and get a nice clean Cut that's also why most of the time if I'm ever using the foam core board I don't use the hot wire cutter It won't get through the foam core because foam core has paper, sandwiching the foam in between it We've got our gear all cut out of the foam Let's peel off our paper, and then we can do a little bit of cleanup work this foam actually sands pretty Well if you use a light grit sandpaper got here some 600 grit sandpaper Which should do an okay job of smoothing it out without really taking too much of it down Our foam gear has been cut and clean and so we would be ready to start putting it into the sand and casting it but We've had some problems with that in the past The molten copper is so dense that it has a tendency to break the sand apart And that's what led to the holes in this gear being full The little sand that was sticking up through those holes broke off and the molten copper flowed in and it really didn't get a very Nice clean cast as you can see So we want to try and keep that from happening this time with our gear and so what we're going to do is Put a rigid shell around The gear that will then be surrounded by the sand and for that shell we're going to be using this wall texture It's a plaster like substance that is normally painted onto walls to make it so they aren't just flat and smooth and boring I guess but what we're gonna try and do is thin this down to a sort of runny paste and Coat over this gear in a couple of layers. We'll do a layer We'll let it dry for 12 to 24 hours, and then we'll do a second layer And that should give us a pretty nice rigid shell that probably wouldn't be strong enough by itself But when we surround that shell with the sand, I'm hoping we'll have a nice smooth Shell that will hold itself in shape even as we pour in the molten copper Now unlike plaster of Paris this stuff just has water mixed into it and isn't chemically Activated by the water it dries out rather than curing As a result it may not be quite as strong as plaster of Paris But it dries out much faster plaster of Paris tends to hold the water in the plaster Sometimes for days and sometimes the only way to get rid of all of the water is to heat it up a lot This should just dry in room-temperature air as you can see this is now fairly runny about the consistency of paint It's gonna shake it back and forth a little bit to try and get some of the bubbles out of it And I'm not putting it in the vacuum chamber one, because this bowl doesn't fit in the vacuum chamber and two, when stuff with this consistency starts to bubble it tends to splash a Lot it would really get the inside of the vacuum chamber messy, so I'm just gonna bounce it back and forth Hopefully, that's removed a bunch of the bubbles now Here's the plan we're gonna take the gear and we do still want it to be open on one side We're going to cast this just by pouring copper out of our crucible directly into the mold Which means one side of it shouldn't have any shell on it. But we do want to make sure that the shell gets all the way up to the edges on all the other sides So what we'll try doing is dip the gear down in not covering one side of it, and then we'll flip it upside down Onto a piece of foil over this block of foam It's pretty good. Just to make sure I've got all the little gaps I'm gonna get a little bamboo skewer and use that to touch up some spots like where my fingers were Our gear now has a nice coating all over it and I think I've really managed to get it onto every square inch of that surface Let's give this a little while to dry come back and add another layer. Our gear has now had a chance to dry for about 24 hours And the shell that we put on to it is nice and rigid Feeling so it's time to go back and add a second layer this time We're gonna be using the same stuff, but we're not gonna thin it out with water We'll take a paintbrush dip it in and paint it all over every exposed surface directly. I'm actually kind of surprised at how little Cracking there was there's tiny little spots where it started to break apart But I actually suspected that we would get more than that. All right our gear is all covered in a new layer of plaster you can see all the brush marks everywhere, but those shouldn't matter because Everything that you can see right now is just gonna be in contact with the sand itself the gear remember is the foam? Inside of this plaster like material, and that's just gonna get melted away when we pour the molten copper onto it. Let's let this dry for another 24 hours And then we should be ready to encase it in the sand and pour our copper The coating all around our gear has had plenty of time to dry and we do have a little bit of cracking forming on it But I don't think that's gonna be a problem because remember this isn't supposed to be a perfect mold It's basically just supposed to keep the sand Away from the foam and away from the copper as we pour that in so it doesn't break off and float on the molten copper So I'm still hoping this will work the plan now is we'll try and peel the foil off Put it at the bottom of our little box And then we'll fill Compacted sand or round it at that point, We should be able to flip it over and have the exposed foam on the top and we can pour our molten copper directly into that. With the mold nice and squished in with the compacted sand inside this box it's time to fire up the foundry and start melting our copper. Ooooh that looks nice, I like that Ooooh that looks good. Oh, bubbling strangely now. The surface is getting all... warped, hopefully that doesn't mean too much as bad is happening at the bottom. That's cool how you can see the sand, drying out around it. The temperature at which copper is Molten, will actually make it fuse onto this steel pan almost every time so we can't use the muffin tin to cast the copper That's why we poured it into the sand. Our pour looks like it worked really well, It poured in flowed into all of the gaps nicely destroying all of the foam And it doesn't look like any of the sand broke off, and floated up So I think that means that the shell we had around it did a good job of holding the sand where it was supposed to be. Now we need to take this out of the sand and see how it's looking. I hope that shell comes off nicely I think what I'll do is try and lift the whole thing out shell and metal all together and just Put it in some water And it might make the shell sort of break apart because the shell should still be super hot Because the copper is still super hot this looks like the only spot where it spilled over a little bit Just kind of weird it went in all flat, and then these bubbles happened afterwards so that might be part of the copper cooling process I'll see if I can dig this out. The shell is breaking apart, that's all right my shells breaking apart a lot. That's still all right Infact, my shell is barely... It's only there in the middle, but let's just see what happens if we throw this into the water. Hopefully nothing terrible Doesn't look like anything terrible happened, there we go Yeah That shell after being hit with all that steam, I think it just kind of falls to pieces An interesting sort of iridescent effect going on on the surface of the copper here I don't know if that is just from the copper itself if that's from some contaminants That was in our crucible if that's from the shell that was made, but it looks pretty cool This worked out pretty well that drywall texturing paste did a very good job of creating a barrier between the copper and the sand and we just had one little spill over point, that was on top, that had nothing to do with the sand, getting into the mold, it just... I added just a tiniest bit too much copper, But overall this works really well, very happy with how it turned out Tune in for our next video where we'll clean up this copper gear, and hopefully make and just a nice, shiny almost mirrored surface in places that should look awesome. 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