Glass Bead Making at Bonfield

Over the weekend at 'Barron's Howe' (Bonfield ON) Neil Peterson hauled up his current version of a glass bead making furnace. Two afternoons were spent with demonstration and teaching, plus further experimentation with this prototype. As with the iron furnaces, there is only minimal archaeology to suggest the actual design of Viking Age glass working furnaces. The physical techniques that may have been used are also unknown. An overview of the furnace in operation. Meghan operates the double bag bellows, with Neil at one of the two working ports set to either end of the furnace.

Neil has been basing his reconstruction on the size of the furnace base as has been found at the excavations at Ribe, Denmark. Right now we have configured the furnace superstructure with the air blast in the middle on one side. On this mark 3 furnace, there is a triangular diverter opposite the tuyere to sweep the air blast towards the two working ports set on either end of the long axis. Each of the work stations have different layouts, in terms of the side port and upper exhaust hole shape and size.

Showing the use of glass rods heated and worked inside the exhaust hole.

When using a modern styled glass rod as the raw material, it is possible to use the hot exhaust gases much like working with a torch would be in standard lampwork technique. The current layout of the exhaust holes is not ideal for this method. Although generally much easier (especially for first time users) there are few actual remains of glass rods found to suggest this method.

Showing work inside the furnace through one of the end ports. Note the small chip of flat glass heating on a piece of charcoal.

The raw material used most often (judged by artifact remains) in the Viking Age were 'tesseri' - fragments of flat glass originally prepared for mosaic work. Our experiments continue to figure out the best way to physically manipulate the often irregular pieces (roughly 1 - 2 cm on a side) to achieve a symmetrical bead.

Readers who wish to follow this series of experiments should take a look at the following articles / postings:
Dark Ages Recreation Company BLOG

Neil Peterson's work on illustrating Viking Age Beads

A look at the current work at the Ribe Viking Centre