I have been playing with the idea of making my own steel for a while but couldn't find the time or the practical knowledge to run a small one-man-operated tatara-like smelter. That is, until I had a chance to watch and help Mike Blue and Randal Graham go through the process.

This is the story of my first run during which I encounter a number of difficulties. The main one being how exhausting is for one single person to run this furnace and pay attention to everything that is going on.

The charcoal was chopped during the days before the run into little lumps about a cubic inch or less. The size of the charcoal lump should be proportional to the bore of the furnace which is 11 inches.

The ore comes from a ceramic supply store. The name of this particular iron oxide is Spanish Red which I thought was quite appropriate for me. It is a light dust that stains everything almost permanently red and contains 80%hematite. Half way into the run I realized that the field where I was working had turned red from quite a bit of the ore dust being blown out of the furnace.

The furnace is based on the shell of a water heater. It is made of three parts to allow for easier assembly and disassembly.

The parts were made mostly of sand and cement. It held up pretty well to the heat but crumbled at the time of taking it apart.

The tuyeres were made of simple black iron pipe fittings.

Here is an additional picture of the bottom part of the assembly after pouring the refractory and letting it dry.

And a view of the assembled parts.

Here is the setup with the smelter put together during the preheat. It is 7:30 AM and I am using a gas burner for the first hour.

At this point I covered the smelter with a refractory blanket to increase the thermal efficiency. That actually worked really well. The temperature measured at the bottom of the top third of the smelter read 1000 degrees F.

I used a home made manometer to gauge the air flow pressure. I was hoping that it will identify leaks as pressure drops and blocking of the tuyeres were as pressure increases. It was helpful to detect leaks but not to detect obstruction of the tuyeres. When you have 4 tuyeres even if one stays open the pressure reading does not change. On the other hand it was very helpful in regulating the air flow from the shop vac. I used the variable voltage knob from a broken halogen lamp to regulate the power to the shop vac. The manometer was indirectly reading the amount of air flow very accurately. Most of the time I run the air at 15%.

 It is 9:00 AM now and the furnace is now running on charcoal now and the first charge of iron oxide is in.. The temperature read 1800 degrees and remained there or above for most of the run. My charges started at 1/2 kilogram of ore and half the way through the run I went up to 1.25 kilograms. I was using about 2 kilograms of charcoal per charge.

The manometer during the run showing the change in pressure.

At 10:30 I heard bubbling at the tuyeres. From that point on things became a bit heptic and I had to work on taping the arches, keeping the tuyeres open and trying to keep up with the schedule of charges. I lost several pounds of weight during the day. A big design mistake was obvious at this point: the tuyeres were set too low and the build up of the bloom and the slag chocked the reaction too soon. The first time I tapped the arches I only had a little bit of slag coming out but I don't think I was too aggressive clearing up a path for the slag to come out. When I did poke a good hole in the arches I had quite a bit of slag flowing out on its own until it cool down and clogged the arch.

2 hours into the run there were sparks coming out of the tap arches every time I open them. I took that as a good sign and kept going for one more hour at which point I couldn't keep up with all the different tasks and I was exhausted.

So I let it burn down after the last charge at 12:00 PM and started to take it apart. The top third of the smelter lifted off easily but the refractory crumbled to pieces on the rims. So much from trying to have a system that was reusable! I could still recycle the parts but they will need to be repaired.

By now the middle part has now been removed as well as the tuyeres. I went to have lunch and came back after one hour to see what I had at the bottom.

After cleaning up the charcoal a little bloom is inside covered by ashes. It looked like Mount Fuji covered in snow.

After cleaning up all the debris and removing the bloom it turned out that the walls held up pretty well.

Here is the bloom. A mere 5 pounds of steel were consolidated and lots of smaller lumps were recovered with a magnet.

The spark test looked good.

This is the largest lump of the bloom divided in two. It resembles an Rorschach Ink Blot Test. What do you see in it?

After polishing the surface and etching a bit you can see all these beautiful dendrites a sign that the core of the bloom was molten at one point.

FINAL SCORES:

Preheat took one hour with the gas burner and reached a temp of 1000 degrees which was enough to ignite the charcoal. After that I used 25 lb of charcoal and reached 1800 degrees in half an hour.

The total time spend putting charges in was 3 hours. I used 80 lb of charcoal and 30 lb of ore over 17 charges.

The bloom was 5 lb in size for the consolidated chunk and about 10 lb more of different size smaller lumps. The total was about 15 lb of returned steel. About 50%.

Now on to making a solid bar of steel out of this stuff...

For the next chapter click here.