Hi YouTube, my name’s Geoff and I’m the
VegOilGuy. One of the things I love about YouTube is
learning new things. It was Grant Thompson’s mini metal foundry
that got me into casting a few years ago and after seeing Nate doing a Copper Gear video
the other day, I thought I’d have a go as well and dedicate the video to the King Of
Random as my way of saying thanks for a great hobby inspiration.
As a subscriber, I wrote to Nate a few days after his Gear video, chipping in my two-penneth
about how he could improve things – yeah right, as if I’m an expert. But I’ve had
such amazing results with my casting method with Aluminium, that I genuinely thought it
might help. He hasn’t replied back yet, but he must
get thousands of messages every day. So I suppose I shouldn’t really expect one. And
of course I’ve never really tried this with copper myself, so it might not work.
So with that in mind, I’ll have a bash today at applying my techniques to copper. But please
remember – this is my first time working with copper.
I couldn’t find a download for Grant’s gear, so I drew something that looked pretty
similar in size and shape, but it’s not very accurate if I’m honest.
I cut this out and glued it to some extruded foam, just as both Grant and Nate have done.
However, I used two thin sheets of foam to gain the relevant thickness.
I sliced this out on my hot wire cutter and then, as is my way, I hollowed out some of
the inner core of the gear. You’ve seen me use this technique before. It reduces the
overall mass of the foam. I genuinely believe it helps.
I soaked the paper side in warm soapy water until the paper fell away.
I then glued the two halves together. I was unhappy with one of the teeth – I’d
cut a little too much away. So I glued on a smaller piece and let the glue set.
I then trimmed this down with a sharp blade and a little sandpaper.
It was then time to add some gates to attach my plaster feeders and vents and these are
easily carved and sanded from foam. These gates get glued and screwed onto the
pattern. I then applied a little candle wax to fill
the any holes and cover over any imperfection, but as this was never going to be a working
gear, I didn’t go mad. Once cool, the wax can be sliced, scraped
or lightly sanded away. You know my method now guys, a bottom flask
with a solid bottom and into this I placed some nicely prepared green sand, ramming it
firmly into place – but not too firmly – then levelling it off with finer sand.
The upper flask was fitted and the foam pattern located diagonally.
I sieved on some fine sand, then sprinkled some loose on top, then pushed this carefully
around the foam with nothing but my fingertips. When the sand was roughly to the level of
the foam, I gently moved it back and used a metal bolt to push the sand into all the
voids, compressing the sand without too much force.
Once I buried the pattern and left only the gates exposed, it was time to remove the screws.
I then pushed on the plaster feeder and vent and these have got temporary paper covers
to keep the sand out. More sand is trowelled in and pushed down
firmly, firstly with my finger, then eventually rammed moderately with the handle of a rubber
mallet. There’s really no need to go mad with the ramming using this technique.
Then the top is struck off and any loose sand lightly brushed away.
I then took a fine metal spoke and poked some holes into the sand. Now these don’t go
all the way to the pattern, maybe stopping half an inch or so above it.
In the background I’ve had my home made electric foundry cooking for a few hours now
and I was aiming for 1200 Celsius. But it’s confession time folks. This is the hottest
I’ve had this foundry and I don’t think the thermocouple is up to the task. It was
only a cheap thing from eBay, just a couple of quid. It’s supposed to be good for 1400
Celsius but I’m not so sure. When it read just 950 C I could actually hear
the copper bubbling inside. I looked in, a tricky task thanks to the blinding white light,
and it was liquid, which should have happened for another hundred and thirty five degrees.
So this got me think the calibration was off or the thermocouple was junk, but either way
I had to make a decision. So at just over 1000 degrees I hit the button, raised the
foundry, a grabbed the white-hot crucible with my tongs.
I poured it into the feeder carefully and it was like a fireworks party.
I suspect the copper was much too hot. I’ve no way of being sure but I suspect I went
way hotter than was needed, especially judging by the very energetic response of the metal,
shooting out both the feeder and vent. Much too energetic!
And I think this accounts for the poor results you’ll see in a moment.
But look at the temperature of the metal in the feeder. The plaster vent and feeder did
their job, keeping the metal molten longer, but that seems too hot for too long to me.
I really think the temperature of that copper was over 1200.
Did you notice the vent holes I poked? I’m used to seeing steam and gas come from them,
but this time there’s actual flame. Amazing.
I left things an hour to cool, then broke away the tops of the feeder and vent.
As I took the flasks apart, look at the drag. Remember, that’s just the sand you’re
seeing. All those colours are evidence of heat and gases escaping into the sand, which
is exactly what we want to happen. The copper gear looks a little rougher inside
the sand than I’d have hoped, and that’s because of all that energetic metal.
Martin our resident casting guru – tells me that if you overheat metal, you can trap
more gasses in it, and I suspect that’s what happened here with all that spitting
copper and this rougher texture. But the sand is nicely blackened, so at least
plenty of gas and heat got out correctly. Now this is the result straight from the tap
– no clean up mother than a swill with water. I find it interesting that there’s no surface
stains associated with the decomposition process typically seen with Aluminium. Perhaps that’s
the higher temperatures burning the foam more efficiently.
So it wasn’t the beautifully straight, sharp, crisp result I was hoping for and have come
to expect from this technique. That meant time more metalwork time, and I don’t enjoy
that part to be honest, so I’m not going to do much… as little as I can get away
with if I’m honest. And this is the result.
Yes there are imperfections. Not it’s not brilliant. It’s certainly not as good as
the aluminium stuff you’ve seen me working on. I’m convinced the temperature played
a big part in this, so I won’t be doing any more copper work until I nail the temperature
issue. I’ll just need to save my pennies and get a more reliable thermocouple so I
can be more comfortable in these higher ranges. But this was my first ever attempt at copper
and – importantly – I’d never have even been doing metal casting at all if it hadn’t
been for the King Of Random. So in the very unlikely event of Grant or
Nate ever watching this video… “Guys, you’re right – copper is tricky. But thanks
for the inspiration and keep it coming. And Grant, if you want this copper gear to put
on a shelf or destroy in an elaborate manner, drop me a line and I’ll post it to you.”
And that’s a finished video. I hope you enjoyed this one guys and if you
did, please like it. If you’ve got any questions on this subject,
drop me a line. Don’t forget to check out my website and
please subscribe if you haven’t already done so.
Look out for my other videos on my YouTube channel and send in any comments and video
requests. So that’s it for now guys, thanks for watching.