Sunday, July 10, 2011

Smelting and Weather?

When I smelt by myself if I have inclement weather I can usually post pone the smelt. I would like to have more people participate. That makes it more difficult to post pone. Some of the pictures I see "easy up" covers. I assume they are not over the furnace. I could get 30 seconds out of it over my furnace :-). At the present time I can not smelt inside either. How do you people handle the poor weather?

Milton


NO worries on weather!

I ran a completely successful smelt one time at -20 F temperatures. It was punishing for us workers, and the preheat was somewhat extended (with wood splits). Once the furnace was to temperature, the difference of 75 degrees (F) in the input air did not make and effect to the operation energy inside the furnace.

In the spring I taught a workshop at Brown University. It pissed rain the whole day. We did keep the charcoal itself under cover. Again once the furnace was running, the small amount of water that hit the top of the furnace never even made it to the charcoal surface.

I'm never smelted in an absolute downpour, but I suspect once the furnace is at operating temperature it will not mater. How YOU react to the weather is an entirely different matter.

Having dry charcoal does make a (big!) difference, but in most of our short shaft furnaces, there is plenty of energy being produced. You will notice a difference in consumption (dry fuel does mean slightly lower volumes used)

We work with a 'farmers market' style tarp (now dedicated for smelter use) that is set about 10 feet back from the position of the furnace itself. This gives us a sun / rain shade. You certainly do get fine pin holes from burning charcoal dust. Screening your charcoal reduces this problem by the way.
At L'Anse aux Meadows NHSC last summer, we worked inside a reconstruction of the original 'furnace hut' on the site. This was a dried turf (peat) walled structure with a pole roof. Wall height was about 6 feet, about 8 feet to the peaked roof. Size was about 10 x 10 with one side open. Absolutely no problems with fire on the roof, a mere 5 feet from top of furnace to ridge line. (Mind you I would not recommend it generally!)

We have smelted a number of times in the winter / early spring here in Central Ontario inside my workshop. Dirt floor, 20 foot peak inside. Main problem is the fine ash that seems to go everywhere!

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