Chapter 2:

Building a Charcoal Foundry

Here again, they told you anything that's not HI-TECH, is no good.


Technology is not an Anorexic's parade on the Catwalk, it grows, it doesn't just change clothes.

Remember the Blimp? Passé? Well, Airships are back, because of new advancements, and of new circumstances, and that's what makes the Tech world advance.

Illustration 14 It all starts with a Paint bucket and a tube...

Now most people think Aluminum is as hard to melt as it is to solder.

Wrong! In fact, it really melts at a relative low temperature, and that, along with it's lightness, corrosion resistance, and non-magnetic properties makes it IDEAL for Tinkerers.

Consider this: They make your PC's Hard Disk chassis out of Zamak, an Aluminum/Zink alloy, and if that's good enough for them...

it should be good enough for most Gizmos!

By the way, if you live on a small Apartment, and/or can't stand the fumes in open air, just line the insides of the thing with Electric Resistance Wires, on a spiral groove you make on the inner surface of the foundry, molded that way with a piece of garden hose or anything else handy.

Remember, IMPROVISE building it... But not when it comes to the safety of Mains-operated electric appliances!

For all other purposes, the principle's self-explanatory, you just put coal on a Paint bucket lined with a sand/fire clay mixture, and a smaller bucket of anything else that:

A It's cylindrical, and small enough to leave the lining 5 Centimeters, or 2 Inches thick;

B It's strong enough to withstand the watered sand/clay mixture being placed, doesn't adhere to the lining, or can be left to burn, like a thick cardboard roll rolled to shape, or a metal plate rolled and held like that using duct tape.

Let's get at it, then:

Illustration 15 The same thing, only G-Sketched

Get a 2 parts sand for 1 Fire Clay mixture, just enough water sprayed on it for it to stick together.

As you may choose a different Bucket size, better get that Paint bucket and fill it to halve with the sand, then half of that volume's worth of fire clay.

Illustration 16 The mold on place

After you've mix it, remove the tube, yes, you need to make a hole on the bucket to fit that tube that hole is as high to the bucket's bottom as the lining's thickness, and fill the bucket freehand, no inner mold, with the mix.

Now, put the mold back in, and pound the mix all around, until the tube, already in it's place is covered. Then, when you remove the mold, it should look something like this:

Illustration 17 If you don't figured it out yet, the tube is pushed back a bit so the mold will fit, then pushed to this position:

After that, putting the mold with some wood bars to keep it centered, just pound the mix, roll the mold, pull it some, pound again, until you've reached the bucket's rim.

Illustration 18 The thing finished, mold off

I have a REAL Furnace I've made, and I'll show it, promise, but already made;

So I've just proved that when you forget to take pictures, it's Wings3D and Google SketchUp to the rescue!

For the lid, use another Paint Bucket, but this time, you better use a thick Rock Wool layer for lining.


It's far lighter, therefore ideal for a lid, so you can move it about without breaking a foot!

Cut the Paint Bucket to four times the clay lining's height, and cut a hole on it's center, 2 lining size's diameter, cut a hole on one side and insert a steel bar. until you have this:

Almost done, what's left is to find something to blow air into that steel tube:

A discarded Hair drier, Hot Air Paint Remover, or you can make a Centrifugal Fan.

Sounds daunting, but it's just an electric motor that turns a disk with some vertical fans, and a can with a lid with a hole, see the drawing:

I think this is self-explanatory, with tin plate, a pair of tin plate cutting scissors, a hand drill and a riveter, you assemble the thing on top of an electric motor, and the Centrifugal Fan will happily blow air into the Furnace, when you fit the Tube adjustment on the Furnace steel tube.

Then you put the coal, ¼ to 1/3 of the Furnace's volume, inside the Furnace, some Fire starting fluid, or briquettes, light the fire, let it spread, turn the air blower, and let the thing ROAR!

The first burn will serve primarily to bake the watered sand/clay mix, just let the coal burn, ¼ just for the baking, 1/3 for the ingots;

You may add some metal, on a strong iron pot or a crucible, just to make some Aluminum or Zamak ingots, just get some sand you put on some large container to the floor, and make a few grooves with your fingers on the sand.

The crucible or pot can come with a handle, mine did, if not, use very good tongs to handle the thing, listen to the Hardware Store Man's advice on that, or DO SOME GOOGLE REASEARCH.

I won't explain stuff here that is available on the Net, you're learning to fend for yourself, do your home work!


Just did all of the above, now what?

Well, now the fun starts;

If you go to the Links section, you will see a lot of Foundry work pages, what's the better one for you depends on what you're planning to build.

Here you can see a work I've done, first melt, had to machine it a bit

For example, if you just want to make small, jewelry or watchmaking size pieces, you can forget all of that you've read till now (ain't I a stinker?), and go to Chapter10, Web Links, visit TEP, and learn about a COOL Pewter melting machine, with only an Electric Paint Remover Blow Gun and other stuff...

But will that melt Aluminum?

And what about your bigger projects?

Or the exelent Gingery Metalworking Shop From Scratch series of books, the green sand, wooden patterns and all, unmissable for some, if not all, Gizmo-builders...

But there's those guys, also on the Links Chapter, that just use Styrofoam use-once pieces, they cut and glue to their heart's content, then put the pieces on old Oil barrels with regular dry sand, submit the barrel, from the top, to a vacuum-creating setup of theirs, pour the Aluminum, and no worries, the things come out fine, and in BIG sizes!

It all depends on you, and what you want to build!!


This is Molten Metal we are talking about, not Play-Doh!

The usual dum mistakes like touching the newly-cast metal are almost unavoidable, I know, 'cos I have done it too, but putting your face in front of the lid's gas exit is A VERY STUPID MISTAKE I thank God it never came to my mind!

Have to take a look at the molten metal?

FINE, take the lid off, or look from afar, and sideways, not on a straight line to it.

Use protective goggles, no Nylon clothes, never mind the heat, use work trousers, leather gloves and work shoes!

Make good planing on the workspace, the trajectories to and from the Furnace, use you freakin' head... Plan things ahead!