Glass Bead Making Furnace

(duplicate post from the DARC blog)



Neil / Ragnar working with the mark five experimental bead furnace.
Trillium War, Whitby ON - July 4, 2009

This furnace is based on the base plate remains found at Ribe, Denmark, dating from the early Viking Age. There was no superstructure preserved, so a number of top designs have been experimented with. The combination of top vent and side port with cover appears to be the most flexible. Most likely a mark six design will be built, as new knowledge is gained every time a serious work session is undertaken.

One key techinque was stumbled upon (pretty much by accident).
An ongoing puzzle has been how the Norse worked with glass tiles (tesseri) as their source of raw glass:

This is a direct method (rather than involving a melting pot or creation of glass rods as intermediate step).
- work is done inside the furnace through a side port
- glass tiles placed on flat surfaced piece of charcoal (which can be used two or three times)
- wait till glass tile heats till edges just start to slump
- make sure your mandrill is well heated (to orange)
- touch mandrill to one corner of the tile to affix small corner of glass
- raise and twirl mandrill. This effectively pulls a stringer shaped finger of glass off the tile.
- now the process is like working with a rod, thickness of the stringer is controlled mainly by height the mandrill is lifted above the tile.
- This appears to reduce the amount of ash contamination, plus produce a correctly shaped bead (rather than the irregular shape produced by grabbing the entire tile at once.

Check the main DARC web site for more information on Neil's ongoing research and experimentation into VA glass beads and their production.

(Darrell)