Parts of a Kiln – Labeled Electric Kiln Diagram

All 16 parts on the diagram

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Outside, lid open 8

Lid A slab of firebrick in a steel band. It swings up on the hinge at the back.
Lid brace It props the lid up while the kiln is loaded and unloaded.
Hinge It joins the lid to the back of the kiln. Some are spring-loaded, to make the lid easier to lift.
Jacket A band of stainless steel wrapped round the firebrick.
Peephole The witness cones can be watched through it. The top one is usually left open while the kiln fires.
Peephole plug A ceramic plug. Lower peepholes are usually fired with their plugs in.
Control box It is fixed to the side of the kiln. The controller in it switches the power on and off to hold the temperature it was set to.
Stand A metal stand made for the kiln. The kiln is set in the middle of it.

Cut open, loaded 8

Firebrick Porous insulating brick that holds the heat in. It is fragile and is handled with care.
Floor Also called the kiln bottom. It is checked for spots of glaze before each loading.
Heating elements Coils of wire that heat up when the current is on. They lie in grooves in the walls.
Element grooves Cut into the inner face of the firebrick. They are kept free of chips and glaze.
Thermocouple A rod through the wall with its tip in the chamber. The controller reads the temperature from it.
Kiln shelves Flat slabs stacked on posts. Their tops are coated with kiln wash so drips of glaze do not stick.
Posts Ceramic props. Three under each shelf are recommended.
Witness cones Small cones set on a shelf. They can be seen through a peephole there. Each bends at its own stage of the firing.

How this list was compiled: Every name checked on 2026-09-30 and kept only where at least two independent sources use it: three kiln makers' manuals, full text on archive.org ((1) https://archive.org/details/manualzilla-id-5887513; (2) https://archive.org/details/manualzilla-id-5889127 and https://archive.org/details/manualzilla-id-5750401, one maker; (3) https://archive.org/details/manualzilla-id-6009304) and (4) Wikipedia, text only: Kiln, Kiln furniture, Pyrometric cone. The manuals were read for the names of parts and what each is for. No maker is named or drawn. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's product, nothing traced. Licence: own work

How it works

The parts of a kiln, on the top-loading electric kind found in school art rooms. The first drawing is the outside with the lid propped open. The second cuts the kiln through to show how it is built and loaded.

Read the full guide

Outside first, then cut open

Numbers 1 to 8 are the outside: the lid, its brace and hinge, the jacket, a peephole and a peephole plug, the control box and the stand. Numbers 9 to 13 are how the kiln is built: firebrick walls and floor, heating elements in their grooves, and the thermocouple. Numbers 14 to 16 are what goes in with the pots: kiln shelves, posts and witness cones.

Shelves and posts together are called kiln furniture.
Kiln wash goes on the tops of the shelves only, never on the lid, the walls or the undersides.

Questions and answers

What are the parts of a kiln called?

Outside: the lid with its brace and hinge, the jacket, the peepholes and their plugs, the control box and the stand. Inside: firebrick walls and floor, heating elements in grooves, a thermocouple, and kiln shelves stacked on posts.

What are the shelves in a kiln called?

Kiln shelves. They stand on posts, and shelves and posts together are called kiln furniture. The tops of the shelves are coated with kiln wash so that a drip of glaze does not stick.

What is the hole in the side of a kiln for?

It is a peephole. During a firing the witness cones on the shelf behind it can be watched through it. Most kilns are fired with the lower peepholes plugged and the top one open.

What is a kiln sitter?

A shut-off device on older kilns with no controller. A small cone is set in it, and when the cone softens and bends in the heat, the device switches the kiln off.