Viking Age Air at Early Iron 4

 Early Iron 4 - in April!    
 From: Darrell Markewitz

Darrell Markewitz will investigate air supply into a Viking Age furnace.

I had not realized how cut up the original description had gotten - and this was the point of a bulk mailing that had been sent out earlier this week

This is from the longer text version:

Darrell's first attempt at a bloomery furnace was at a research session for Parks Canada in an attempt to re-create the first iron smelt in North America by the Norse (about 1000 AD). Since then, he has concentrated on re-discovering lost Northern European techniques from the Late Iron Age, using the process of experimental archaeology. Darrell was a team leader for all of the previous Early Iron symposiums, as well as another core member of the Smeltfest research workshops. He has taught historical iron smelting both in Canada and the USA, as well as taking part in research projects in Denmark and Scotland.
www.warehamforge.ca/ironsmelting

Darrell will be undertaking an experimental archaeology project which also will provide a more basic level furnace construction and operation sequence for less experienced bloomery iron makers. The furnace will be a 'Norse short shaft' type, to be built over the early afternoon on Friday. The smelt on Saturday will employ a 'bog ore analog' and the experiment will centre on using multiple double chamber bellows linked to a bladder as a possible method to produce high air volumes. Participants actively sought!
Friday afternoon - build
All day Saturday - smelt

The core here is my ongoing research into possible VA iron smelting techniques. Archaeology actually only gives us broken remains of only the last step in a complex multi-step process, and usually heavily eroded at that. Modern re-constructions using various variations on Norse type twin chamber bellows most commonly produce smaller, lacy blooms. The few artifact blooms surviving are larger and more dense, more like the blooms made using much higher air volumes.
My question is 'how do you get high air volume from small capacity bellows?' One at least theoretical possibility is linking a number of smaller 'blacksmith's' bellows via a leather bladder (animal skin). Placing a board and weight on top could serve to modify delivered air pressure (another important factor effecting smelting furnace dynamics). This system may also suggest something about the social dynamic around small scale iron production in the Viking Age.

I do hope some of the readers in the NE region of the USA might consider Early Iron 4.