Well, I am serious enough to be doing a little armchair ironmastering to see whether it can even be done. Some others have expressed interest, so perhaps a little discussion will prove worthwhile. I've already managed to learn a fair bit about the facilities and process, but much more remains to be uncovered. Nevertheless, there are some immediately evident and fundamental issues.
The first is whether the process will even work at scale. If the goal is to make iron in a small furnace, then there are a number of relatively compact options (in the 10' stack height range) from much older periods. But if the goal is to replicate charcoal-fired smelting as it was done in the late 18th and 19th centuries in New Jersey, then the furnace will have to work at 1/3 or 1/2 scale, and that is an open question. Overman indicates that stack height has a huge impact on the quality of the iron, and the types of materials required.
The second is construction. Charcoal-fired smelting of bog ore (limonite that is primarily hydrated oxides) can be done in a fairly simple furnace design. For example, a barrel furnace with a rounded crucible, rather than the more complicated design with a seperate crucible surmounted by a conical furnace featuring bosches. However even a simple barrel furnace in the 10' stack range would involve a lot of masonry work. Some modern shortcuts would probably have to be employed. For example, I have seen discarded sections of concrete sewer line in the five-foot diameter range here and there. Two sections of that, the lower one having a 'T' opening of 3 feet diameter to serve as the work arch, and the upper being a straight, or nipple, section, stacked one atop the other, might make the exterior. An internal volume of stacked firebrick might then provide the furnace chamber, with sand being filled between. Just an idea.
The third issue is materials and batch preparation. We'd need a source of ore. Not a small thing since many such were worked out over a hundred years ago, and whether they have replenished as geologists expected I don't know. If we find it we'd need permission to dig it. Then we'd need to prepare it. Overman is unclear which preparation steps bog ore requires. Certainly it needs to be crushed. It may need to be roasted. Roasting could potentially be done in the same vessel, or in a pottery kiln, but it is something to take into account. Not sure how it would be crushed. These are some areas where we would probably need help from people with specialized tools or facilities. I suppose if we operated a furnace on a very small scale then we might hand-crush the ores, but I am guessing it would be a very labor intensive technique. In addition we would need chunk charcoal; not powdered brickettes but real charred stuff. We would also need crushed seashells or limestone, to serve as a flux.
Lastly, safety. Reading in Overman and other sources makes it clear that these furnaces, when in blast, were dangerous places to be. He writes about "burning out the timpstone" with fragments of broken, burned stone shooting around in the work arch. Other stories are related of "puffs" or burn-outs where flame erupts from the top of the furnace. If the process is off just a bit in terms of temperature or humidity you can get cinders and clinkers choking the tuyeres, or accumulating in the bottom, and requiring the breast to be opened and the blast to be put down so the problematic material can be raked out. The hearth material is critical, and if it doesn't withstand the temperature and chemical properties of the melt you could have some really disasterous results. Imagine several hundred pounds of molten iron and slag getting free of the furnace! There would have to be a platform and rail at the top so the "bankmen" can charge the ore and charcoal batches safely.
I have a lot more reading to do, and it might be possible to make a crucible and run some small trials to confirm materials and process before a large investment of time was made. I think generally-speaking that a furnace could be built and run, but it would require a dedicated team of people with sincere and lasting interest. It's not like putting together a trebuchet and tossing a few pumpkins around. Still, it's a really intriguing idea, and it might be that support could be had from interested parties, assuming we had people with historical credibility involved.
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