Building a Micro Furnace, Metal Melting for Beginners

Introduction: Building a Micro Furnace, Metal Melting for Beginners

This project is for those that want to try melting metal without outlaying a huge amount of cash.

This is a very quick and easy project that will help you decide if you want to melt metal.

Materials for the furnace body:-

1 x coffee can (or a container roughly that size)
1 x K26 fire brick
Some Kaowool
Some Kaowool hardener, (or a something to seal the Kaowool)
4 x 1/4" coach bolts
8 x matching nuts

To power the furnace you will need a Bernzomatic hose torch, this is the most expensive part, but can be used for other jobs, so if you decide you don't like melting metal you will have a very useful torch for your tool box.

To use the furnace you will need a thimble crucible, and this is necessary as it is used to determine the internal cavity of the furnace.  Fortunately these are relatively cheap.

Your standard K26 fire brick is soft, and can be sawed, and shaped easily. 

I cut the fire brick in half for the furnace body, and with the other half I cut that in half again to act as a lid.  I drilled a hole in the centre of the lid to act as an exhaust.  You will have a piece of K26 fire brick left over, just store that someplace as a spare lid.

I used a 1/4 inch drill bit, to carve out the cavity, and used a piece of masking tape attached to the drill bit to act as a depth gauge.  A drain was drilled in the bottom, and a hole for the  torch tip was drilled in the side at an angle.  The torch inlet was positioned at the base of the furnace cavity.  (See photo 2).

Four holes are drilled into the coffee can, the coach bolts, and nuts are fastened.  Drill a hole in the side of the can matching the torch inlet in the fire brick.  Jamb the firebrick into place, you may need to take off the corners of the fire brick if the fit is too tight.

Pack the fire brick into place with Kaowool.  Apply the hardener to the exposed Kaowool.  Remembering to put some hardener into the torch inlet with the tip of your finger.

Wait until the next day and your furnace is ready to run.

Initially I designed this furnace to melt , and alloy bronze, however I have melted silver and gold in it successfully.  It doesn't have the ability to melt platinum or steel. 

Others have used my design and used a hand held propane torch instead of the Bernzomatic hose torch.

Have fun melting metal, and remember molten metal is very hot, so be careful.

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    4 years ago

    Just Substitute the K26 and kaowool with sand and Plaster of Paris. Mix Sand and Plaster 50/50, let harden and drill some holes...Or use a paper or foam cup to make the furnace hole and drill the torch hole.


    8 years ago on Introduction

    where do you get the K26 fire brick?
    where do you get the Kaowool?
    where do you get the Kaowool hardener?

    All of these things are extremely hard to obtain in most parts of the world...


    Reply 8 years ago on Introduction

    Well that's the trick isn't it. I had to hunt in Australia to find the components, but I did find them.

    The K26, Kaowool and Kaowool hardener can be usually found in pottery supply stores.

    If they don't have that specific product in stock, they will have something very similar. As long as the product does the same thing, it doesn't have to be a brand name. ;-)

    If you are in a part of the word that doesn't have any of the suggested products or equivalent, then you will need to look at tribal methods for melting metal (also fairly easy to do... maybe another instructible?).