Historic Air?

I have been doing some background research into air delivery systems for Pre-Conquest, mainly in relation to my ongoing experimental iron smelting. As well, I have worked with a fair number of modern and historic forge set ups.

On a recent NORSEFOLK2 discussion, here have been some suggestions given about possible air systems for use in the forge. Right off the top, you have to determine if you attempting HISTORIC or MODERN equipment.

Some notes on the suggested equipments:

'Double Bellows': Two chambers, one beside the other, separate exhausts connected by a Y tube. Alternate filling and exhausting each side to produce constant blast.
Evidence suggests individual chambers roughly 30 cm wide x 50 cm long.
ONLY documentable system for the Viking Age.

'Great Bellows': Two chambers, one on top of the other. In northern Europe, typically a top mounted leaver pumps the bottom chamber, which in turn fills the upper chamber. From the upper chamber air is delivered to the forge.
May vary in size, but typically very large, on the order of 50 cm + wide by 100 - 150 cm long, thus not portable.
I have not been able to date this bellows any earlier than about 1300 +/-

'Box Bellows': One large rectangular box with a central plate which can be pulled/pushed back and forth. Valves on both sides, so as one side fills the other exhales.
Can vary considerably in size, from about 30 x 30 x 60 cm to several metres.
Asian ONLY - never used in Europe.

'Skin Bag': One or two individual leather bags with some method of closing an open top, the lower edge leads to forge or Y tube. I have seen either two sticks or a plank with a central hole and hand strap used to control this.
Size limited by effective operation method, bag roughly 30 x 30 x 30 (depending on closure method)
Pre Roman ONLY (often referred to as 'Celtic Iron Age')

I have seen a kind of concertina bellows set up, which may date back to the 1700's.
Other systems in use by modern blacksmiths ALL date no earlier than 1870's.

There are a number of posts discussing the development of a re-construction Norse era forge set up over on my own blog (Hammered Out Bits).

If you are attempting an actual recreation of Norse smithing equipment, your only option (based on evidence) is a charcoal side blast forge using a double bag bellows. Used correctly, this small scale set up will produce welding temperatures. The main hurdle for the modern smith is learning to work inside the limitation imposed by the much smaller heat zone created. A reconstructed Viking Age forge will only heat about 4" or so of your material to correct forging temperatures, so you need to work quickly and efficiently.






Images off the DARC web site - at Haffenreffer in 2004.

Darrell