Glass Furnace
The melting tank that holds glass at working temperature, day and night, for the whole life of the studio.
Gathering
| Capture velocity | 0.5 - 0.8 m / s at the hood face |
|---|---|
| Duct diameter | 150 - 200 mm |
| Airflow | 600 - 1200 m³ / h |
| Material | Galvanised or stainless steel |
| Overhang | Minimum 300 mm beyond the furnace footprint |
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
A hot shop produces carbon monoxide, nitrogen oxides and fine metal oxide particulate, and all of it rises. The exhaust hood is a shaped canopy that captures that plume before it reaches breathing height and ducts it outside. Capture velocity at the face of the hood is the number that matters: below roughly 0.5 m per second the plume escapes around the edges and the hood is decorative.
Safety notes
- Fit a carbon monoxide alarm in every room with a gas-fired furnace or glory hole.
- Make-up air is not optional. A hood that starves the room pulls combustion gases back down the flue.
- Clean grease and dust from the duct annually. It is a fire load sitting directly above an open flame.
Using it well
Practical guidance
- Test capture with a smoke pencil rather than by smell. If the smoke drifts sideways, the airflow is short.
- Keep the hood overhang wide enough that cross-drafts cannot shear the plume away from the canopy.
- Balance the make-up air so the room stays slightly negative without pulling from the flue.
What to look for
- Tapered canopy that matches the furnace plume
- Removable grease and dust filter panel
- Ducted to outside with a weatherproof cowl
- Compatible with a make-up air inlet at floor level
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 exhaust hood
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
See the furnace & heating workflow
Read the category overview, or jump into the 3D Studio to see these tools applied to a live piece.