15 years ago
While my gas forge is very nice, and does the job well, I am
discovering that using it is just way, way too hot for the summertime,
even with vent fans right above it- it's like pointing a jet heater at
As I recently joined the local blacksmithing club, I now have a source
for good coal, and I'm thinking that this may be the way to go for
summertime use- from what I've observed, they tend to be quite a lot
cooler than a forced-sir propane rig unless you're right next to them.
So here's the deal- I can make just about anything out of sheet goods,
bar stock or tubing. I don't have a cupola (yet), so casting iron is
out of the question for now. I have a very lenient employer that
allows us to use materials, within reason, for personal projects- and
I also have a bit of stainless steel that I bought a while back
availible for whatever I need. I've got access to all sorts of
industrial-grade toys for building this sucker, so that is what I'm
going to do.
But, since I enjoy having the flexibility to make things that I need,
I try to make sure that I use as little time and material as possible
when doing government work. That's the point of this post- I already
know how to overbuild just fine, but I need to figure out what I can
get away with without sacrificing quality.
I will be fabricating the firepot, grate, clinker breaker, and table
from stainless steel, unless there is a good reason not to do so.
Commonly availible sizes range from 16ga to 7ga (.063"-.188" nom.)
While thicker may be better, it represents a signifigant increase in
difficulty and cut time on the laser to use a thicker material. One of
the guys I work with has a bit of stainless tubing that he estimates
is about as thick as 12 ga sheet metal (.105") that is about the size
of a coffee can that he is willing to give me, as he has no real use
for it. I am considering using this for a firepot, if it is thick
But there's the trouble- there is plenty of information regarding cast
iron coal forges, but I have seen very little about any made from
stainless steel. What I need to figure out is what material I need to
have to make decent parts that will hold up to the application.
What I have in mind, if it will work, is 12 ga tubing for the firepot,
a laser-cut 7ga grate, a 12-10ga table with a 1-2" lip around the
edge, and an 11 ga clinker breaker. The blower piping will most
likely be black iron pipe from the hardware store, though it may be
stainless or 4140 depending on what we have floating around in the
back shop where we keep tubing and bar stock.
Any comments on this would be welcome- I have worked with stainless
steel quite a bit, but that has never included working with it at a
high temperature. If I use mild steel, I can build up to .25" thick,
or thicker if I make a square firepot rather than a round one (though
that would require a little shopping, and would delay the project.)
If the 12ga firepot is way too thin, there is a possibility that I can
get it step bent from thicker material in two half circles and weld it
together, but that is a reasonably signifigant investment of the brake
operator's time, and I'd like to avoid it if the thinner firepot will
work. In a worst-case senario, I'll track down some cast iron pipe,
but I'd just as soon use the stainless. While we have some other
grades, I will be using 304- that's the common stuff, and it's less
expensive than some of the other materials.
We're kind of in a lull at work right now, so this is the perfect time
to do this- when there is no chance that it will interfere in any way
with running "real" parts.
For what it's worth, the fixation on stainless here is a result of a
few different factors- first, I am fairly certain that the melting
point of stainless steel is higher than that of carbon steel, though I
have not looked it up. Second, my gas forge, fabricated from
cold-rolled carbon steel, and painted with hi-temp barbeque paint has
developed some surface rust after less than six months of use. And
third, I just want to use it because it's cheap and easy for me to get
(There has to be *some* compensation for living on the edge of
outright poverty in a small job shop, after all...)
The hood will likely just be made from whatever galvanized sheet we've
got tucked away. It doesn't seem necessary to go all-out with the
stainless for that, considering the price of the stuff these days.