Personal projects / Materials & heat
Stainless-steel hemisphere furnace
My active project: a high-temperature furnace with a stainless-steel chamber and tungsten resistance heating. The goal is to melt sapphire and ruby.
Open the numbered review →Installed electrodes
Photo 503
The inside of the stainless-steel furnace hemisphere after the electrode feedthroughs were fixed in place with epoxy. This shows a later stage of the assembly previously photographed with temporary clamps.
Flange finishing
Photo 254
Brazing had warped the stainless-steel flange, preventing it from seating correctly. I built up the surface with low-outgassing epoxy, which releases little gas in a vacuum. A flat reference disc was used to transfer a flat surface to the epoxy.
Chamber and frame
Photos 252–253
The vacuum furnace mounted on its support frame during assembly. The vacuum-system connections were not all attached at this stage.
A second view of the furnace and its support frame while the vacuum system was still being assembled.
Earlier fabrication
Photos 246–247, 249, 251
The latest iteration of my high-temperature vacuum furnace, shown during assembly. The stainless-steel hemispheres have feed-through tubes and KF25 vacuum connection flanges brazed onto their surfaces. Brazing joins metal parts using a melted filler metal.
This stainless-steel hemisphere was intended to form a water jacket, carrying cooling water around the furnace. The thin steel warped too much during brazing, so I later replaced this part with a plastic version.
An inside view of the stainless-steel furnace hemisphere shown in Photo 246, revealing the openings and joints for the chamber fittings.
Cleaning flux residue from the stainless-steel hemispheres after brazing. Flux helps the metal-joining process, and its residue needs to be removed afterward.