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Casting a Copper Gear Success!

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 pore 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
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 sandwich Inge the
foam in between it we’ve got our gear
all cut out of the phone let’s peel off
our paper and then we can do a little
bit of cleanup work this phone actually
sans 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
with the mold nice and squished in with
the compacted sand inside this box is
time to fire up the foundry and start
Oh bubbling screams Lee now the surface
is getting all warped hope that doesn’t
mean too much as bad is happening at the
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 scene 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 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 back
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
that she’ll 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 Esther 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
spillover point that was on top that had
nothing to do with the sand getting into
the mold it just I added just those
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 it just a nice shiny almost
mirrored surface in places that should
look awesome hey guys thanks for
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fun be safe and see you tomorrow [Music]
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