Blacksmithing
and Cutlery
by Gérard HEUTTE
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Making a ground forge
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This article presents the realization of a forge built directly on the
ground. The hearth is delimited by bricks. The air flow comes from side.
The target is to carry out a simple, fast and cheap
construction.
Materials
Construction will be made with fire bricks
(refractory bricks or if lacking, of usual construction bricks).
You can of course use junk bricks. it matters little that
they split with time. For the phase of construction, let the bricks soak a few hours
in water before the assembly phase.
The supplying price of refractory bricks (new) is about
0.5 Euro each.
The assembly of this construction calls upon a mixture
known under the name of Brasque with the following composition:
(1) Clay of potter. You can buy it or get in the field. To be powdered.
[ 4 volumes ]
(2) Powered charcoal. [ 4 volumes ]
(3) Sand (silica not calcareous). [ 1 volume ]
(4) Possibly, a handle of dried grass or of straw
These proportions are not imperative. It exists
many formulae.... Mix well the ingredients and humidify
the mixture until getting the good consistency. Prepare some tools like
trowel and spatula.
Construction resulting is not among the most robust, but that
allows easy modifications and repairs.
The supplting price of the clay is about 7 Euros per 10 kg.
Instead of Brasque, it is possible to use refractory cement.
Construction will be more solid. On
the other hand, the cost strongly increases!
The tuyere allows sending air in the hearth. Here, I
have made the simplest. A metal tube (diameter 30 to 40 mm)
bent is used. No need to plan a grid or a system of
cleaning, since the tuyere horizontal and that nothing will fall in.
In the below sample, the side walls forces to
bend the tuyere. In other configurations, you can use a
simple straight tube right put on the side of the hearth.
Steps of the realization
1 - Prepare the construction area, by
cleaning it and by levelling surfaces coarsely. Place the
base of the forge by spreading out a good layer of Brasque then
by posing a layer of brick above (photo below on the left)
2 - Position the tuyere. It is
necessary to specially cut a brick to integrate the
tuyere in the left wall (photo below on the right)
3 - Build the walls. The bricks are
posed flat rather that on the side for a better stability.
Then, you can pass to the completions. In this example,
the rear of the earth is protected by a raw of tilted bricks.
(photo below on the left)
4 - Then, it should be waited enough for drying during a long
time (2 to 3 weeks). The potter clay must be cooked to get solidity. Make a fire in
the hearth and rise gently the temperature. Make three or
four thus heating. Push a little more ventilation each
time of heating to go more and more high in temperature.
And here is the forge ready to be used... (photo
below on the right)
Some tricks and ideas
It is useful to place behind the forge a support to make there rest the
side of the heated parts.
The lateral air flow allows using borax to weld in the
forge without disadvantage. The residues (extremely
corrosive) fall on the bottom of the forge on bricks without
damaging the tuyere. If wished, the bricks of the bottom
can be left free (just put down), to be able to change them at will.
Another possibility is to cover the bottom of the forge
with brasque, which will be replaced once damaged.
This equipment has some advantages; A low cost and a great facility
of construction. The main drawback is that this construction is irremovable.
Some improvements are possible. An opening at the back of the forge will make it possible
to heat the medium area of large parts. A lid (removable) of refractory brick is possible
to create a vault, facilitating the heating of heavy parts.
Variant...
Here is the quick version.
This forge was built at the Festival on Iron in 2006. Initialy,
it was not plan, but due to the high number of blacksmiths on the stand, a solution was required.
So :
> Some refractory bricks
> Brasque
> A makeshift blower
> 45 minutes of work
Ready to start the fire !
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