SWNZ Forums

Ideas, tutorials, questions relating to armour, costumes and replica props from the Star Wars universe
 #24383  by badges2nz
 Sun Oct 22, 2017 12:34 am
I have some shop light fittings that are made from cast aluminum, these could be quite good for re melting down
 #24387  by Blaxmyth
 Sun Oct 22, 2017 11:53 pm
So this morning I fired up the gas burner to test casting aluminium into a green sand mould. The small crucible wouldn't fit into my gas forge, so the metal didn't melt as well as I hoped, but I managed to pour enough to test the concept. And it worked! :)

I made a green sand mould for a tusk, which involved making a damp mixture of fine beach sand and ground up kitty litter (bentonite clay), then tamping it down around a previously turned tapered former. When the former was withdrawn, the packed sand kept the shape, ready to receive the aluminium. The idea is that the sand is porous enough to allow any steam to vent through the sand instead of exploding out the top.

There was not enough molted aluminium to fill the mould so my finished tusk is only about 2/3 as long as it should be. When it was demoulded, I filed off the sand and fitted it into the lathe for freehand turning. You can see some rough areas from the casting which I decided not to remove by turning, because I quite like the weathered look.

Next step is to excavate the coal forge from behind the shed, ready for a big pour next weekend. The coal forge is much hotter and copes with a large volume of metal than my gas burner, so should get some large castings hopefully.
Gas burner set up outside. Too small for the job.
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Mould ready for use. Sand packed down tightly around the former, which is then removed.
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Raw casting out of the mould, ready for cleaning sand off prior to turning on lathe.
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Partly turned the rough surface. Using an old wood chisel.
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Starting to take shape.
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 #24389  by Blaxmyth
 Mon Oct 23, 2017 12:02 am
And here's some more pics of the work in progress. The last two are after buffing the casting on a cloth wheel. It gives a shiny appearance without looking like it was precision machined .
Turning aluminium on wood lathe. Slowest speed and being careful not to force the tool into the metal.
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There's a few blemishes in the metal, but I regard them as being merely pre-weathered.
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Hole drilled into end of tusk. That was tricky as had to pad the tusk with masking tape so the pliers wouldn't mark it. Will use leather next time.
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This is the good side after careful buffing on a cloth wheel.
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 #24393  by TIE1138
 Mon Oct 23, 2017 4:02 am
Yes, these aluminium pieces will add that extra something when the costume if finished.
 #24405  by Blaxmyth
 Sat Oct 28, 2017 7:27 am
More progress from today. I thought I had made enough green sand for casting the eye stalks, but ran out, so made do with some hastily made stuff which was too wet. So learning happened.... But the casts are going to be OK and once I make a wooden chuck to hold the eye stalks, they should turn OK on the wood lathe.
Anyway - three pepakura mask/helmets for underneath the bandages. I'll fibreglass these with cloth, so they will be strong enough to fix the castings onto. The pep files are mine and they're free if anyone wants a copy. Just sing out.
Pepakura masks.
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Turning the head spikes from some aluminium rod that Nick K gave me. They look a lot better after they were buffed. I have drilled out a 3mm hole for mounting them onto the mask.
Head spikes in progress.
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The crucible worked perfectly and the coal forge easily coped with the large volume of aluminium.
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The hardwood cores were OK. They did their job, which was to form a hole through the finished casting so it didn't need to be drilled out. But next time I'll make one from plaster of Paris. It'll need to be really, really well dried before using.
The hardwood core charred about 1mm deep, but it worked well considering it breaks most of the rules of sand casting.
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Hot and covered in sand. They will need turning to size on a lathe, and the tail end cut off. The interior hole is longer than the finished eye stalk, so it won't need drilling.
The charred wood should give a weathered effect to the inside of the eye stalks.
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I figure that Tuskens would have had a restricted access to technology, so sand casting seems a logical way of creating the metal bits of their costumes. And the play value alone is amazing! :D
More to come soon hopefully. Really enjoying this project. :)
 #24407  by MattG
 Sat Oct 28, 2017 9:43 pm
Blaxmyth wrote:...
I figure that Tuskens would have had a restricted access to technology, so sand casting seems a logical way of creating the metal bits of their costumes....
Agreed, it totally works for this.

Looks like the under-mask is a great fit for Pepakura too, without needing an armour-level of finishing.

Awesome project... very cool to see your progress pics.
 #24408  by Blaxmyth
 Sat Oct 28, 2017 11:22 pm
Thanks for the feedback, Matt. Here's this morning's progress, posed on an authentic, still-used-every-day Sand Person's glove.
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The next tusk looks like it'll have a casting flaw near the base, which I'll leave in place if it doesn't weaken the piece too much.
 #24428  by Blaxmyth
 Mon Nov 06, 2017 6:06 am
All of the round bits are ready now, except for figuring out a way to cut the slots in the eye stalks. Think I'll jack up a holder for them and use the power hacksaw to cut down to the halfway mark. Probably. Don't fancy using the hand hacksaw - it tends to wander off the cut line.

There are a few casting marks and a void or two, but I really like the hand-made look they give. I don't see Tuskens as being equipped with CNC lathes, and they'd probably use whatever scavenged metal they could find. Bit like me, really. :ohwell:

Next step after cutting the slots will be to make a mould for the snout, and then cast and polish it.
Tusks before and after polishing.
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