Smalt Hot ShopBook a bench

Ghent · Furnace lit since 2014

Cobalt glass,blown at 1,148 °C,then cooled for a day.

Smalt is a four-bench hot shop running one cobalt furnace around the clock. We make small runs of deep-blue vessels, teach the pipe to beginners, and publish every annealing curve we fire.

Book a hot-shop sessionRead tonight's furnace log
  • Furnace 1,148 °C
  • Glory hole 1,260 °C
  • Annealer 468 °C ↓
  • Bench 02 in use
Furnace, holding
1,148 °C
01
Benches on the floor
04
02
Annealing cycle
14 h
03
Cobalt oxide by weight
3.1 %
04

01 Process

Four temperatures between
sand and a shelf.

Every piece in the shop passes through the same four stations. The numbers are the ones the pyrometer reads, not the ones in the textbook.

  1. 01Gather

    1,148 °C

    A honey-thick turn of glass.

    The pipe dips into the crucible and rotates once, twice, until the gather reads the size of a plum. Too slow and it sags; too fast and it tears.

  2. 02Marver

    980 °C

    Rolled flat on cold steel.

    The steel table pulls heat from the skin of the gather and centres it. This is where the smalt frit goes on — crushed cobalt glass that becomes the blue.

  3. 03Blow

    1,260 °C

    One breath, then the bench.

    A short puff opens the bubble. The rest of the shape comes from jacks, wet newspaper and the glory hole, reheating every forty seconds.

  4. 04Anneal

    482 °C → 20 °C

    Fourteen hours of waiting.

    Every piece goes straight into the annealer and cools on a written curve. Skip it and the glass keeps its stress — and cracks on the shelf a week later.

02 Furnace log

Tonight's anneal, in the open.

Load 0412 went in at 18:40: nine bottles, a bowl and two beginners' paperweights. The annealer soaks at 482 °C, then walks down on the curve below. Collect from 09:00.

Load
0412
Pieces
12
Now
468 °C
Ready
09:00
50037525012500h2h4h6h8h10h12h14h482 °C soak · 2 hstrain point 370 °C
°C over hoursLoad 0412 · annealer B

03 From the last firing

Three shapes, one blue.

Small runs of eight to twelve. When a load is gone it is gone; the cobalt batch never mixes the same way twice.

SM-217

Tidewater bottle

Cobalt over clear · 31 cm

€ 340
SM-221

Low weather bowl

Smalt frit, cased · Ø 24 cm

€ 260
SM-226

Night drop vase

Steel-blue, optic mould · 22 cm

€ 290

04 Sessions

Pick up the pipe.

Thursdays to Sundays, two students per bench, closed-toe shoes and cotton only. Everything you make goes through the same anneal as ours.

Next open bench · Thursday 17:00

The furnace is already hot.

Write to us with a date and how many of you are coming. We reply within a day, usually from the bench.

bench@smalt.exampleVisit the studio · Dok Noord 7
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