Friday, October 31, 2008

DARC Fall Smelt

Saturday November 8 - Wareham

Regular Readers - You would have all gotten some the background for the Icelandic smelt series that Neil Peterson, Kevin Smith and I have been undergoing of late in bits through earlier postings (search HALS) A nicely formated overview is now available on the Wareham Iron Smelting site.

Our last test smelt at Thanksgiving was just barely snatched back from disaster. Obviously we need more practice with the blow hole and bellows plate set up. It was clear that adding the lack of ability to access the tap arch space was a bit too much. I don't think the overall layout for the HALS set up is a problem of itself, other than the restriction that will be imposed by the location of the bellows.

(left) Bellows plate and blow hole with set back bellows tube - just at the point were the slag bowl started to freeze over and restrict air flow.

(right) Solution that saved the smelt - reverting to ceramic tube as insert tuyere.

(left) The lower rear wall after the smelt. Note the broken area and deep fractures to the upper left. The front (above the tuyere) was completely broken away.
The smelter shaft constructed for Thanksgiving is pretty much shot. At this point there is only about half of it remaining. So it will be just as easy to build a new shaft. (The weather is supposed to warm up here over the next couple of days.) I'd like to try to work with the horse manure for the entire furnace (more like Michael Nissen does). Whether I can gather enough dried manure (this late in the season) will be the bottle neck here.

I will forge up a tapered bellows pipe like the one Michael has described. Remember we had started to lean that way with the copper tuyere. Ken Cook and Gus Gissing have long been suggesting this approach

On ore, our stocks are starting to deplete. All the taconite got used up on the last smelt (athough I'm sure we can get more). There is some of the DARC dirt 1 remaining, but not enough for a smelt on its own. There is some of the poorer Virginia Rock roasted but in need of crushing. I have several hundred pounds of the hematite grit, and suggest mixing those two.
Altogether there is enough of the Williamsburg rock for one smelt. Maybe enough raw for three using the poor Viriginia mixed 50/50 with hematite. I will be picking up another bag of spanish red to mix to DARC dirt. There is also a pail full of gromps - but best these be used in a smelt in a standard furnace.

The last hole in supplies is charcoal. We currently have enough on hand for one full smelt and a bit (I think there are about 100 kg taken altogether, mainly as Black Diamond ) We have been more fuel efficient of late, mainly by going straight to full sized ore charges and reducing the length of burn down.

So in detail:

work inside the Hals layout
new 5 cm smelter shaft
bellows plate and blow pipe
switch to tapered tube (blower)
hang air pipe system to free tap arch
ore 50 / 50 poor Virginia / hematite (22 - 25 kg?)
(aim for Hals sized bloom - 15 x 15 x 10 / 5 kg)

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February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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