Glass Furnace
The melting tank that holds glass at working temperature, day and night, for the whole life of the studio.
Gathering
| Material | Fused silica or clay-bonded alumina |
|---|---|
| Capacity | 5 - 120 kg |
| Maximum temperature | 1500 °C |
| Thermal shock resistance | Fused silica high, clay-bonded moderate |
| Wall thickness | 18 - 35 mm |
| Compatible glass | Soda-lime, borosilicate, lead crystal |
Compatible glass types
Soda-lime
Borosilicate
Lead crystal
Compatibility assumes the tool is rated for the working temperature of that glass family. Check the maker's documentation before use.
Overview
The crucible is the consumable heart of the furnace. It must survive months of contact with molten glass and metal oxides at 1200 °C while being repeatedly exposed to cool air every time the gathering port opens. Thermal shock, not melting, is what eventually destroys one. Fused silica crucibles handle shock best; clay-bonded pots hold their shape longer but demand a gentler daily routine.
Safety notes
- A cracked crucible can release molten glass through the furnace base. Inspect the drip tray after every session.
- Never quench a hot crucible. Thermal shock will shatter it and spread glass across the floor.
- Handle empty crucibles with a proper lifting cradle, never by the rim.
Using it well
Practical guidance
- Match the crucible to one glass chemistry. Switching a pot from soda-lime to borosilicate rarely works well.
- Keep the glass level above one third of capacity; a nearly empty pot overheats at the walls.
- Skim the surface before gathering to remove unmelted batch and oxide crust.
What to look for
- Thick base for even heat distribution
- Rounded interior corners that are easy to skim
- Sized to the furnace crown opening for simple changes
High temperature tool
This tool operates in or near the working range of molten glass. Read the safety notes above before first use, and never work with it without eye protection, heat-resistant gloves and working extraction.
Reference information only. Specifications are published ranges drawn from manufacturer documentation and normalised for comparison. They vary between makers and between individual units. This page does not sell or endorse any product, and does not guarantee any result. Follow the equipment manufacturer's instructions and take hands-on instruction before operating hot glass equipment.
Related
Tools used alongside the crucible
Glory Hole
A reheating chamber that brings a cooling piece back to working temperature without touching the main furnace.
Shaping / Blowing
Annealing Oven
A front-loading chamber for bringing finished pieces down through the annealing range under control.
Annealing
Kiln Controller
The programmer that executes a ramp-and-hold schedule and holds the furnace to it.
Annealing
See the furnace & heating workflow
Read the category overview, or jump into the 3D Studio to see these tools applied to a live piece.