CROCKETT’S COUNTRY WAYS: Making a furnace
Short of something to do on a sunny Sunday? Head down to the woods and get stuck into making one of these fabulous furnaces; it’s a great way to keep kids (and adults) occupied!
In the last issue we made some charcoal. This time we’re going to use the charcoal as part of a process that is thousands of years old. Before we start production of metal tools, we need to build our furnace.
YOU ARE GOING TO NEED:
! A rubble tub or bucket
! A metal tube
! A means of lighting the fire
Start by clearing the ground that you’ve selected as the site for your furnace, with a diameter of three to four feet. It needs to be level, so you may need to dig the top soil over to overcome any slopes or dips. This is essential, since when you light a fire in your furnace the heat will go straight up regardless of how sloping the ground is; you need to have the heat rising centrally through the furnace and not heating one side more than another. Once your site is cleared, spread a layer of sand over it [pic 1]. This will prevent the extreme heat from burning any roots below.
Next, it’s time to get mucky. Fill a bucket with clay (clay soil is ideal, but you may need to get it in from somewhere else). Mix in some water until it becomes easily malleable and can be shaped without difficulty.
Place your metal tube on the sand. If you want, at this stage you can use multiple tubes. The tubes allow air flow to help fuel the furnace, and the more air, the better. Take a handful of damp clay and make a long sausage from it. Place it at right angles over the metal tube. The sausage should be in a curve so that when you add another sausage it completes a circle about 12" in diameter [pic 2].
Now make another sausage and place that on top of the first layer. Keep making sausages and placing them in circles, one on top of the other, until you have a structure about 12-15" high. Any left over clay should be placed around the base to support the outside in a buttress formation. This will add to the strength of the furnace. By this stage it should look like a volcano.
Next, carefully take out the metal tube and make sure that you can see through the hole into the heart of the furnace. Replace the metal tube and light a wood fire in the bottom of your clay furnace [pic 3].
Gradually feed the fire with firewood until you have a decent fire with a bed of embers in the base. To speed up the process you can use the metal tube and the bellows to direct air into the base of the established fire. By doing this we are slowly drying out the clay furnace and setting it hard [pic 4].
To complete the process we need to increase the heat even more. You can do this by adding charcoal. The charcoal will produce a heat which is truly intense. Once you have a furnace full to the brim with burning charcoal you can leave it to burn out and cool down [pics 5 & 6].
It is a good idea to keep the furnace out of the rain, so I use the inverted rubble bucket to cover it and keep it dry. I push a stick into the hole where the metal tube goes to deter small creatures from making a house in the furnace [pic 7].
You now have a furnace that will be up to the job of making bronze or heating iron to the extent that it can be worked. You can even make your own bullets! This is a project that is a fun afternoon’s work for one or more people. It’s particularly popular with children (and adults who haven’t tried growing up yet!).
“GRADUALLY FEED THE FIRE WITH WOOD UNTIL YOU HAVE A DECENT FIRE WITH A BED OF EMBERS IN THE BASE”