[MR] [MedEnc] Portable easily made forge / Re: blacksmithing

[rmhowe]

The most basic forge can simply be a hole in the ground with
a pipe (tuyere) supplying air from beneath or beside it.

Or:

An easily made portable forge can be had with some basic 2" 
pipe fittings, an electric blower, and a cast iron brake drum. 

I have had three forges in my time, a brake drum forge 
(actually my favorite), a very large commercial Buffalo forge,
and a cast iron bandsaw brazing forge in which large tongs 
were heated to braze huge bandsaw blades together. I sold the 
Bandsaw brazing forge because it got too hot to be anywhere near. 
I traded the full size forge eight years ago when it became 
impossible for me to hammer much anymore, with a few other 
items to make a fair trade for a milling machine/lathe combination.

To make an easily transportable Brake Drum forge you need:

A brake drum from a car. Larger car sizes are preferable. 
(Truck brake drums are huge, deep, and have huge holes.)
These are found at any scrapyard.

Some fire clay, and some Hydraulic cement to mix it with 
50/50, obtainable at a building supply place.
Something to mix it in. A plastic bucket for example.
Something to trowel it in with. (Plug your blower holes first.)
or 
Some -soft- refractory brick to cut to fit the bottom
of the forge. You can cut this stuff with a hacksaw.
If your local brickyard/home supply place doesn't have
it try a pottery supply store.

You also need a set of -2"- (preferable) or 1 1/2" pipes:
A pipe flange for the bottom of the brake drum, where the hole is.
In my case I scrounged around and found an old cast iron
gear to put over this. The center of the gear had a one
inch hole in it and I drilled the outside of the gear with
a number of 3/8" holes at an angle tapering to the center
to create a focused air blast a few inches above the gear.
This is where you obtain maximum heat.
You could also use a cast iron drain plate or some holed 
stainless steel to help cover the hole in the bottom of 
the Brake drum over the 2" pipe, which is large enough to 
allow chunks of coal/coke/clinker to drop down it. 
Ordinary steel will burn through because of the carbon in 
it. Cast Iron won't burn easily and stainless would have 
to melt. To drill stainless steel you will need to buy
or borrow a cobalt steel (some say C or M42) drill bit.

Rest of pipes:
2 six inch long threaded pipe nipples to screw above and 
below a 'T' connector. The upper one screws into the flange.
The lower one screw into the Pipe cap or oil drum cap.
An oil drum cap to screw on the bottom of the bottom 6"
nipple to function as a clean out. I used a piece of
strap steel bolted to the cap with a counterweight to
simply allow me to raise it with my foot to clean
the pipe out. You could just stick a nail in the lock
holes that are in these caps. If you can't find one
you can simply use a pipe cap. You need a way to clean
out the pipe either way. 
A foot long piece of pipe threaded at both ends.
to screw horizontally into the 'T" fitting to connect
it to the blower.

Some bolts and nuts appropriate to what you are bolting
through. 

A Drill and a few metal bits.

A Piece of Sheet metal to make a blower cover out of.

A little knob and screw.

Most hardware stores have all of the above in stock.

A blower:
This can be a 120 volt electric blower with plug and
in line switch (buy and install it in the hot side of
the wire) or a 12 volt blower to hook up to your car 
battery with a set of alligator clamps. Or both interchangeably.
In my case my initial blower had a square hole, I made a
wooden block to fit the opening, screwed the block inside
the square opening and drilled a hole I could thread the 
1 foot long pipe into. (Alternately you could use a hair 
dryer, or a vacuum exhaust. They just aren't as controlable.) 

If you are going to be working on damp ground I recommend a 
three wire system hooked up to a portable GFCI or plug it to an 
in line GFCI, also known as a Ground Fault Circuit Interruptor. 
If you can't find a place to connect the green wire 
to on your blower, attach it to a bolt on the outside motor casing. 
This is so you won't get a fatal shock. If you don't know 
for sure what you are doing, ask an electrician or look 
in an electrical book. 

(I got my sophomore housing at college because my predecessor 
at the house electrocuted himself with a vacuum cord he'd 
dropped into a puddle he'd made washing his car mats.
I am told that can be a slow way to go.) 

GFCI's can be had for as little as $10 or less. They only 
work on three wire grounded circuits with Black (hot)/ 
Green (Ground) / White (Neutral) wires. GFCI's cut the 
circuit before you can receive a fatal shock. This is what 
is required within six feet of water outlets in your house 
as well. Look in the kitchen and bathroom. They usually 
have a test and an on switch on them. 
Portable ones are $10-35.

Hot black wires go to brass colored screws, White to the silver 
colored screw, green to the green screw or wire or to the bare 
wire without any insulation inside the wall box.
(My wife could have easily died when someone hooked these up
incorrectly and hotwired a new stove case. She did get a shock.)
If you are wiring in a GFCI wallbox remember to cut the power
at the main panel. Test to make sure it's off. A radio or light
that is turned on will tell you when it is off if you don't
have an electrical circuit tester.

Northern http://www.northernstores.com/
and stove supply stores sell 120 volt blowers.
So does American Scientific Supply or Surplus Supply usually.

Blowers also exist within old air conditioners.
These can be 120 or 240 volt in larger ones.
(The problem with old air conditioners is that they
also contain freon, and if you rupture a pipe getting
one out you can blind yourself with the spray. I don't
recommend this, but if you dig one out of one of these
at the very least wear eye protection, with or without
a face shield.) Getting one out can be difficult, so
I recommend a different source. Call around.

12 volt blowers can be picked up at any auto scrapyard.
They are used in the car heater system under the dash
board. Alligator clamps may be had at Radio Shack or an auto
supply place. Make sure you put the insulators back on their
handles. Or put a lighter receptacle plug in instead.

A blower's blast is simple to control by simply putting an 
egg shaped piece of metal over the intake hole with
a small bolt in the small end of the egg shape to pivot
on. I also put a little knob on mine opposite the pivot.
Sliding it to cover or uncover the intake hole changes
your airblast to the forge. 

When you are not heating metal switch the blower off. 
This saves fuel, the fire won't go out.

In my case I mounted the whole thing on some old metal stool
legs bolting the leg tops to the bottom of the brake drum. 

Basic set up:
Brake drum on top, thick rim horizontal.
 _____________________ 
|_____________________|
 |_____         _____|
 |     \ _  _  /     |-- fire clay/cement
 |______|_| |_|______| infill here.
       '-|__|-'  bolted together
         |  |
         |__|   
        |    |_  Tee fitting.
        |      |-----------|
        |     _|-----------| to blower
        |____|
         |  |
         |  |
        _|__|_
     (o|______|0) pipe tank cap / cleanout.

Alternately you can set it up on blocks instead of putting
legs under it. The blocks go on either side of the bottom
of the brake drum. Mix the fire clay/hydraulic cement
and cover the area inside the bowl on either side
of the blower hole(s) in the bottom. Plug the holes
first. Any bolting/assembly should be done before
you lay your fireclay/cement.

These things make an interesting place to have a
cookout/party session around as well (when the wind
doesn't shift your way). A hot dog can be done
over wood scraps in about half a minute, or a 
marshmallow in about five seconds. My blower at
full opening would produce a wood fire about a
foot wide and four feet long. Coal/Coke is a bit
more controllable. Coke is coal with the impurities
burned out of it. Charcoal briquettes are easily
obtained. Just get an adequate supply.

That in-line switch really helps.
You can obtain an in-line cord switch anywhere
that sells electrical supplies.

You also need a little can with holes in the bottom
and a steel strap handle bolted to it to control
the fire as a sprinkler. You need a water bucket
anyway to quench your steel in. 
A piece of 5/16' iron made like a poker with a 90 
degree bend at the end to pull out clinkers. 
Clinkers are what is left when the coal burns itself 
out. I bent the other end of mine to make a handle shape.

This forge will get hot enough to easily burn steel up,
so watch your pieces. A beginner also needs thick leather
gloves, a real pair of American-made Vise-Grip pliers 
(trade name, better than the softer Chinese imitations)
(round jaws style recommended) and a smooth faced hammer.
Other hammers with crossed straight and ball peen heads 
will help. Any damage to the hammer face or your anvil 
will transfer with each blow to your piece you are working.  
Leather gloves will smoke before you feel the heat. 

Use some eye protection. Red hot steel produces scale. 
Hot scale or embers hurt. For a smoother finished item, 
brush off the scale each time with a long handled wire 
brush before you hammer it. Natural fiber clothes are a 
*lot* safer than synthetics.

Steel anvils tend to ring. Cast iron kind of clunks.
Cast iron anvils are a lot more prone to spalling or
throwing off chuncks. Hitting it with a hammer and listening
might help you find a better one. Some have steel welded
to a cast iron base. A good quality anvil is about $4+
per pound. Centaur Forge is on the internet. Cheap 
Chinese imitations claim to be useful. I don't happen to
have one. Rail Road Rail can be made into an anvil.

Since I am writing this in the U.S.A. I am using electrical
terms familiar to us. Your overseas wiring may be different.

Master Magnus Malleus, OL © 2002 R.M. Howe
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