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What are Furnace Beads?
These are pics of pulling the cane to make glass furnace beads or cane
beads.
They're odds and ends of pics from 2003, 04 and 05.
The basic idea is to make a cane with a hole in the center then cut it
into bead size pieces which are finished out by tumbling.
Murrine are done the same way but without the extra required to put a
hole in the middle or tumble finish. You're designing murrine for what
you'll eventually see in cross section.
Murrini and the canes they were cut from.
OK, Here we Go...Let's Make Some Furnace Beads
Gathering the white glass from a small crucible full of hot white glass
that is sitting in the back of the glory hole underneath the hatch I'm
lifting with my left hand.
I just dipped the blowpipe into a pot of white glass and I'm letting
the extra drip back into the pot. This will be the white core of the
furnace beads.
Closing the hatch in the glory hole as the white glass cools a bit.
I'll take one or two more gathers of the white glass..
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Marvering it out, which is smoothing and shaping the glass on a steel
plate by rolling the gather of glass back and forth on the steel.
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After re-heating the white glass in the glory hole (glowing hot device
in front of me in the pic) I blow a bubble into the gather of glass.
The bubble eventually becomes the hole in the middle of the bead.
Dipping the white glass with the bubble in the middle into a pot full
of hot colored glass in one of the glass furnaces.
"Tailing off" the colored glass, or letting the extra hot glass drip
back into the furnace while you spin the gather of glass.
Back to the marver, where we shape up the colored glass we just picked
up on top of the white glass.
This is one way you could put a ribbed texture on the outside of a
gather. That texture would stay there even when the cane is pulled out
and will be there in the finished furnace bead.
If you wanted square furnace beads you would start with a square
gather. This one is not quite shaped up yet but you get the idea. You
can control the shape of the finished furnace bead by shaping the
gather into a square, triangle, etc.
The glass gather has to be kept hot, and at the same heat throughout.
This means a lot of reheating it in the glory hole and marvering to
keep it in shape and cool the exterior until internal and external heat
are close to the same.
Reheating the glass gather looking from another angle.
The tip of the gather of hot glass is cooled by dipping it in water to
harden it. This hardened part is clamped in a homemade tool to hold it
and then the cane is pulled out. You can see the tool opened up in the
pics up above.
A close up of the tool
The first cut, cutting the cane from what's left of the gather on the
blowpipe.
Cutting up the rest of the cane. The wooden cradle holds the cane so
it's easier to put it into the annealer. An annealer is something like
the kiln
you'll see in a minute. This
bring the temperature of
the glass down to room temperature very slowly. This is necessary to
relieve all the strains in the glass.
Shoveling the canes into the kiln/annealer
Straightening out canes. It's a bit over 900 degrees F. in there so you
have to be quick.
All set! Ready to close the door and let them anneal.
After the canes are annealed and cooled down they're cut into
individual furnace beads on a lapidary
saw .
The final step is tumbling the rough cut furnace glass beads in a rock
tumbler using a series of decreasing grit size abrasives to
round and polish them. This takes many days, which is one of the
reasons furnace beads are expensive.
