Building a Better Propane Tank Furnace

This furnace performs well and can melt brass on only 2 psi of liquid propane gas using my custom designed forced air burners.

Health and safety warning: Casting metal is a dangerous activity. Molten metal can be hazardous to your health. Zinc fumes can induce flu-like sickness. Regular masonry can explode if exposed to high temperatures. Always use a respirator when working with ceramic fibre insulation. Always stabilize any exposed ceramic fibre insulation included in a furnace build.

The primary goals of the project were to create a well-insulated, highly efficient furnace - in this regard I consider the project a success. My previous furnace was so inefficient that I had trouble melting metal before the gas supply tank frosted over. The improved insulation and combustion efficiency of my forced air burners completely eliminates that issue.

Soft firebricks were used to insulate the furnace body; I used Fusion360 to design custom brick grinding jigs that achieved a very precise, reproducible fitment. The furnace was designed to fit a ProCast No 4 Clay Graphite crucible (available from PMC Supplies).

Although this furnace was specifically designed as a metal casting foundry furnace, I have no doubt that these construction techniques could be used in to build other types of furnaces (e.g., smithing forges, heat treating ovens, etc...)

It is worth highlighting the major advantages of this method over a more traditional build using castable refractory:
1) Operational Efficiency - The soft Firebricks are much lighter than castable refractory, and do a better job of insulating the furnace. This means that my furnace heats up faster than one made with castable refractory, and uses less fuel to melt a similar amount of metal
2) Repairability - Since they are not cemented in place, each brick in my furnace is individually replaceable. This is useful because they will inevitably need replacement as they erode away over time. The brick upon which the flame impinges will need replacing first, and this is an easy operation. The bricks could even be rotated to prolong the service life of the furnace

Project start: 2022-07-15
Project end: 2022-07-28

Resources: Fusion360, Da Vinci Resolve, Canon EOS70D
GrabCAD: https://grabcad.com/library/propane-t...
Instagram:   / cigzntylrpe  

Chapters:
00:00 Intro and purging the tank
01:59 Prepping the furnace body
06:54 Shaping the bricks
11:14 Blower insertion opening
12:11 Furnace lid
16:32 Painting
17:22 Final assembly and test firing
19:05 Safety hazard
19:38 Machining the cast sample

Music:
Reclamation - Silent Partner
Parasail - Silent Partner
Cloud Patterns - Silent Partner
Glue - Mikos Da Gawd
Moon Monorail - Fluffy Ducks
Idea 170 - Fluffy Ducks
Grut - Patrick Patrikios
Righteous - Silent Partner

Uploaded: 2022-09-14