I've used wrought iron and shear steel in some of my knives for years, but have only helped out with smelts and am yet to commit myself to running one (huge investment in time and materials with the risk of it going totally Pete Tong! :O ). So today instead of tidying the workshop in preparation for a course, I built an Aristotle furnace. For those that don't know what it it is, an Aristotle furnace is a tiny furnace for remelting bloomery or scrap iron. The resulting material is similar to bloomery iron (or steel) but cleaner, similar to the Japanese Orishamagani (or however it is spelled!). It is also very quick and cheap to run! Skip Williams and Lee Sauder (A couple of clever American blacksmiths) came up with the concept years back and I have been meaning to have a go for years
So here is my first attempt!
The furnace was built around a large Coke bottle and made from the clay that my workshop is sat in. Normally the clay would be tempered with dung, but I wondered how well it would stand up without it (I've used it this way for forges for years afterall). On the most part, not too badly but I will add some organic matter next time. I found a small blower in a corner that I bought years ago because it would 'come in handy one day'. Once it was good and hot, I started feeding in some crappy mild steel barstock from my rusty pile in the corner.
As one bar sank below the coals, another was fed in. I stopped when all 699g of rusty iron was gone. I was a little impatient and probably started feeding a little early, so it took about 45 minutes for all of the metal to be consumed by the fire. I let the charcoal burn down a bit and then tried to remove the mini bloom from the bottom. Unfortunately it was stuck fast and I cracked the furnace in trying to get it out. So I hit it with a hammer and did a Blacksmiths' Caesarian on it!
Knocked the furnace walls from the bloom. It seemed pretty solid at this point and ice and heavy, so I could be certain that I had metal!
While it was hot and instead of going home to walk the dog (sorry Saxen!), I lit the coke forge and hit it some more. What can I say, I'm a kid that wants to stay out playing a bit longer!
and because its a cool picture:
At this point I have just worked it on all sides to consolidate it a bit and weld any loose bits together. It welded absolutely fine and with virtually no cracking apart, so I'm a happy bunny thus far. It feels fairly stiff, lets see what the sparks say
Yeah baby!
Then I really did have to go homeI'm now tied up teaching and demonstrating until next thursday! So I don't get to see how it forges and what it will become until the end of next week!
Oh incidentally, after consolidation into this bar; the 699g of mild has become 415g of higher carbon steelI'll be doing this again!
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