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.