There is a larger, constantly on flame. It isn't that the forge is
bigger, but you're heating a larger volume, all the time.
A coal forge is great when you want heat in a specific place or shape,
just build the fire to suit. A propane forge is often better if you
need an even heat over a large area (twists, tools). You can do both
with either, but having both is convenient.
Henry Kolesnik wrote:
Ummm, I would have said that BTUs was BTUs. I think the difference is in
how you use them. A well insulated and efficiently managed gas forge should
blow off way less heat than an open coal forge.
Even heating such as when heat treating a longer blade can be a real pain in
the butt with a gas forge. Depends on the design. As a rule of thumb, if
you want the same temp all around, you would want it larger in diameter as
the length of the work goes up. Not sure of the ratio but I'd say about 50%
of the length in diameter. I've never used coal myself but I've seen some
examples of arranging a charcoal forge for heat treating and it was
simplicity itself if you're treating long thin stuff. Just make the coal
bed the length of the work and stick the work in a pipe and lay it on the
coal. You could do that with a camp fire.
I don't agree. A coal forge allows you to build just the right sized
fire; a gas forge has to be large enough for whatever you want to put it
it. This means that a gas forge is larger and loses more heat. It also
stays on all the time. If you kept the blower working on the coal, it
would put out a lot more btu's than a hand crank forge.
So I think a gas forge does put out more btu's (stays hotter on average)
and is a larger fire, with more heat.
Alright - I can see your point. Can't argue the logic there ;-) Like I
said, I've never used coal. Seems like you would loose a lot of heat with
the open setup but so long as you built the fire with efficiency in mind you
could keep it relatively small... I am stuck with a given volume of heat
with the gas but I can manage the efficiency of that too. Kind of depends
on the job at hand and I've never worked it indoors. Still, you can build
the forge to the type of work you plan to do. I've got a simple design that
is cheap and easy to build (has its drawbacks too...) and I built two of
them at the same time. One is quite small and the other is a bigger general
use unit. All they are is a heat canister. I build them to be desposable.
The torch is the important part and is applied where and how I need it.
I'm not an advocate of any particular method. I just know what works
There are some real good posts so far.
Another thing or two:
If you go with charcoal, you could use a hand cranked blower and
therefore have an easily portable setup. If you go with propane, then
you have to fight that battle or "naturally aspirated" or (blower)
forced draft. The forced draft, of course, requires some sort of a
blower. And some say that you can't weld well with a naturally
aspirated propane forge. By the same token however, some say it's
pretty hard to forge weld with charcoal, too.
I know several guys who make their own charcoal and a few who use it
exclusively. It works for them. I only use it when I have to. I
prefer coal, for reasons already mentioned, but I have a propane forge
that gets a fair amount of use, too.
In summary, don't overthink this. Go get a fire going one way or the
other. Nothing is forever. Sooner or later you get another source going.
Jacob Hawes wrote:
As you would with a naturally aspirated burner. On the other hand you can
run a blower on battery power.
Crap. all you need is enough BTUs for your forge volume and an Oxygen lean
atmosphere. A good naturally aspirated burner will do both if forge and
burner are well designed (and matched). If you make your own burners then
results will vary according to how well you did. I eventually gave up on
making my own and bought a T-Rex and won't use anything else as long as they
are available - though I have a home built I could use to add more heat if
It's all in managing your atmosphere. You can do that with charcoal too.
Amen to that! Work out the bugs as you go and have fun. Problems and
solutions are a matched set. Life would be boring without them.
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