Introduction: How I Built a Foundry Furnace in a Bucket
I built a foundry furnace out of a 6 gallon steel garbage can.
Inspired by several other youtubers and their ideas (like the King of Random--RIP!, Geoff of VOG, and Paul's Garage), I built this backyard propane furnace inside a 6 gallon steel bucket in order to melt metal and cast in molds in my home foundry. I ultimately want to be able to cast a bronze sculptures, and this will be the easiest way to do it using fire bricks, kaowool (a type of high-temp ceramic fiber blanket), and castable refractory cement. These materials, unlike concrete, cinder blocks, and regular bricks are designed to withstand temperatures up to about 3000 degrees F.
Here's the first part of my 3 part how to videos:
BE CAREFUL: I'm just showing you how I built this. I'm not saying it's correct, and I'm not guaranteeing you won't be seriously injured or killed if you do this. Do backyard metal casting and foundry work with great care and responsibly! Use proper PPE when doing this, too! I've seen guys on youtube pouring molten metal in pajama bottoms and sandals and it makes me cringe thinking how injured they could be if some of that metal were to crackle and jump over to their feet!
This is a great tool to add to your forge and blacksmithing hobby because you can mold and cast nearly anything you can think of once you have the ability to melt metals. you can also try your hand at creating alloys.
When you go to buy the supplies to build this, I'd suggest you check your local foundry supplies places for things like refractory and crucibles.
Here's a list of materials I used to build this Foundry Furnace:
--Kaowool (Ceramic Fiber Blanket)
--Mizzou Castable Refractory
--Behrens 6 Gallon Steel Garbage Can with Lid (cheaper at hardware stores)
--Goede Propane Burner
--18v Cordless Drill
--18v Angle Grinder
Step 1: Step 1: Safety First!
You are going to potentially be working with extremely high temperatures and molten metals, so make sure to use the appropriate PPE. That includes eye protection, a face shield, leather apron, heavy pants, leather boots, and welding gloves at a minimum. That said, when we're talking about molten metal spitting around at 1000 plus degree in temp. your PPE can only do so much, so the best protection is to be very careful and not let molten metal go spitting around your shop in the first place!
Here is a link to considerations of PPE from a professional foundry organization.
Step 2: Refractory
For this project, I use kaowool, castable refractory cement, and fire bricks. I do not recommend regular concrete or cinder blocks. These are not meant for extremely high temperatures.
Step 3: Assemble the Refractory in the Bucket
I started by putting fire brick on the bottom of the bucket and lining the sides with ceramic fiber blanket (also called kaowool). I put an interior cardboard cylindrical mold used for concrete to make the inner portion of my mold and then packed castable refractory between the kaowool and the cardboard mold.
You will also want to cut a hole through the bucket and through the refractory mold to set the propane burner at an angle so the flame shoot into the middle chamber of the furnace swirls around your crucible.
See part two of my video for more visuals.
Step 4: Make the Furnace Lid
The lid of the Furnace should also contain the ceramic fiber ( kaowool), and also castable refractory. I added a mesh of steel to act as a rebar grid. Let the lid and bucket refractory cure overnight.
Here is my video explaining things more in-depth.
Step 5: Fire Up Your Furnace
Turn your propane burner on low and let the furnace heat up for several hours to dry it out and temper the refractory.
After that, Put some dried aluminum cans in my crucible and melted them into a puddle. I poured it into an old muffin tin and made my first ingot!