Wear safety glasses while working with an angle grinder so you don’t get any metal scraps in your eyes. Be careful of the cut edges on the garbage can since they may be sharp and could cut you easily. If you don’t have an angle grinder or you just want a smaller forge, you can also use a 10 US qt (9. 5 L) steel bucket that’s 11 in (28 cm) tall.

The side hole will be where air or gas enters your forge to circulate the heat. Don’t put the hole directly along the bottom of the garbage can or else it could get plugged up if there’s a spill inside the furnace.

You can buy ceramic fiber wool from home improvement stores or online. Ceramic fiber wool may cause irritation if it comes into contact with bare skin. Wear long sleeves and work gloves to help protect yourself.

You can buy rigidizer online. Label the spray bottle you use for your rigidizer so you don’t mix it up with other bottles you have. Some ceramic fiber wool is pre-treated with rigidizer and will start to harden when it’s exposed to air. Check the packaging on the wool to see if there are any special instructions.

You can buy premixed furnace cement from home improvement stores or online. You don’t need to use furnace cement, but it can help prolong the life of your furnace and create a smooth, clean surface.

Be sure to use a hole saw attachment made for metal or else you may damage the bit. Never use a lid that doesn’t have a vent hole or else pressure could build up inside the furnace and cause it to explode or fail catastrophically.

Wear long-sleeved clothing and a dust mask that’s rated N95 or better while cutting and working with the wool since it can cause irritation and itchiness. Always check the MSDS label on the ceramic wool you’re working with and follow any safety precautions listed on it. If the wool doesn’t stick to the bottom of the lid, you can spray a heat-resistant adhesive on the lid before pushing the wool onto it. You can buy heat-resistant adhesive from hardware stores or online.

Don’t leave the wool over the hole or else your furnace won’t vent properly.

You can apply rigidizer with a paintbrush if you don’t have a spray bottle handy.

Put cardboard or shop cloths down before you apply the cement so you don’t accidentally get it on anything.

You can buy a furnace propane burner online. Don’t use a regular steel pipe for propane since you won’t be able to control the flame as easily.

You can buy couplers from your local hardware store. If you don’t have an air blower, you can use an old hair dryer on the highest fan setting to move the air.

You can attach any propane tank to your furnace, but small tanks will run out faster while you’re running your furnace.

Use the valves on the propane tank and burner to control the size of the flame it produces. The flames from your furnace may come out from the vent hole you made in the lid, so use caution while you’re handling it. Charcoal furnaces can usually reach a temperature of about 1,200 °F (649 °C) while propane can reach 2,300 °F (1,260 °C).

This furnace will melt low-temperature metals, such as aluminum and brass.