Overview

Annealing is a curve, not a temperature. The controller holds the piece above the annealing point long enough to relax stress, then brings it down through the strain point at a rate the glass can tolerate, then lets it fall freely. A multi-segment controller does this unattended, which matters because the critical cooling stage takes hours and cannot be watched.

Safety notes

Fit an independent over-temperature cut-out. A stuck relay on a controller will destroy the kiln and everything in it.
Check the thermocouple lead for a short before every long unattended program.

Using it well

Practical guidance

Write the schedule around the strain point, not the annealing point. The strain point governs how fast you may cool.
Thicker work needs a slower ramp in both directions, not just a longer soak.
Log the actual curve and compare it to the setpoint. Drift is the early sign of a failing element.

What to look for

Multi-segment ramp, soak and cool programming
Deviation alarms that catch a failing element early
Manual mode with a hard-wired safety limit
Schedule storage that survives a power cut

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.

Annealing Controller

Compatible glass types

Overview

Using it well

What to look for

Tools used alongside the annealing controller

Annealing Oven

Kiln Controller

Annealing Kiln

Diamond File

See the annealing & finishing workflow