Some of my earlier furnaces
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Click on the pictures for a larger view
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It's perhaps fortunate that I haven't got pictures of all the furnaces I've built, otherwise this page would get very boring!
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Where it all started
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After buying Dave Gingery's "The Charcoal Foundry" This was my first charcoal/paraffin blowtorch furnace. I used "home dug" clay(see "Some Thoughts" page) clay dug from a ditch at the top of my road, mixed with some sand I had left over from a building job.
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The blower is a spin drier motor and fan with a biscuit tin as a fan housing and a piece of exhaust pipe pop riveted in place for the air pipe. Not the most efficient centrifugal blower, but more than enough for this small furnace.
The blowtorch is not the "standard" sized paraffin job, but a 5 pint beast with an impressive flame and an impressive fuel consumption to match!
From the first time I lit this furnace and poured some aluminium into a brick, I was totally hooked!
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My Giant Cupola
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After making several different sized charcoal furnaces which I mainly fired using different types of coal,I decided to try a cupola. I don't have a lot of space here, and my neighbours are very close, so something "modest" was called for!
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This was made from an old fire-extinguisher, (something poetic there? white hot furnace in a fire- extinguisher!)
It had a 4" bore and actually worked! But it was very fussy with its bed height and the size of the coke pieces.
I started off with just a single tuyere, then fitted two with a Y branch air pipe.
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I decided that this "monster furnace"was just too much trouble and gave it away, my early furnace days were very hazardous for any visitors to my house, everybody left with a "superseded" furnace whether they needed one or not, my Great Aunt Gladys was a little puzzled with hers, but it looks very nice with a Geranium in it.
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Now we need to fast forward a bit, I had started with my experiments with waste oil by converting the furnace at the top of this page, unfortunately my old computer decided to burn out loosing me all of my pictures that I hadn't got around to putting on disc!
Based on those experiments I built this one, my first furnace using "proper refractory". By the time I gave this furnace away, it bore very little "working resemblance" to its original concept.
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Burning wood Waste veggie oil I think this was copper
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Firstly, please ignore the mess in the background!
In the early days with this furnace I burnt a lot of wood in it, old pine offcuts melt aluminium nicely, this had a 10" bore which allowed for enough wood to melt a 2 pint stainless steel crucible of alli. per load.
The oil burning method I first used on this one couldn't burn engine oil, only W.V.O. but it was an encouraging start!
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Melting cast iron with coke Don't mention the ladle handle!
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(I was pre-heating the ladle on the bricks over the exhaust flame and when I picked it up, the handle fell off! I had molten iron about ready to tap, and in a desperate panic, the only ready to use handle was this pathetic strip of metal, not recomended!)
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The oil burning was working but only just well enough to melt copper (and that was on a good day!)I thought at the time, ok. I can melt alli, brass and bronze with waste oil, and then use coke for cast iron. So the next modification was to cut the bottom out to create a drop bottom, and to cut out a second tuyere, to make this a "batch melter". I've found that any solid fuel furnace I've used, burnt unevenly unless they had at least two tuyeres.
This worked from the start, but every time the bottom was dropped, the lining cracked a little more due to thermal shock, also it took a fair amount of coke to fill it up. Read any information on cupola furnaces and they need repairing almost every time they're used, I decided this wasn't the answer!
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Burning a little rich in this picture It don't need to fit in to melt
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Cracked it! Bear in mind, I'd been trying out all kinds of different ideas to get this waste oil burning cracked for a long time now, when I finally found out what I needed to do it was so simple I felt foolish!
I could get cast iron to a "melted, but not fluid" state on waste oil, I then switched to diesel to reach pouring temp.
As you can see from the second picture, if you can melt directly into the furnace with a spout to tap the metal out again. Not only does the scrap not need to fit in the crucible, it doesn't even need to fit in the furnace! A couple of pieces of brick or blocks to act as a partial lid (if necessary) and away you go!
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Direct melted copper Poured into an open mould A copper sundial
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This sundial is actually a reject, I should have made a pouring well to one side of the cavity and cut a gate to allow the copper to run in. Pouring directly into the cavity caused the moulding sand to break up, also there is some slag inclusion, this is actually iron slag left in the bottom of the furnace, there's a story behind this, maybe another time!
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The Artful Bodger's Iron Casting Waste Oil Furnace is a better designed version of the furnace above, it will direct melt in the same way. But I have included all of the lessons learned from this one to create a far more efficient design which has an outstanding performance. Apart from one trial, I have never had to resort to diesel or any other fuel to boost the heat, I have done all of my iron casting on FREE waste oil, in fact using even a small percentage of diesel in the fuel needs extreme care!
I can easily melt the surface of 1700deg.C. refractory lining just on waste oil, I did quite a lot of damage with the diesel added.
The picture below shows it burning waste engine oil, one mould is for aluminium, the other is for cast iron.
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