The Coal Forge Remake From Lessons Learned

After my initial design and a few days of forging I decided it was time to make some major changes to the forge.

I’ve left images of several iterations I went through before landing on this final configuration. It was truly a learning experience. I put the forge on wheels so I can wheel it outdoors. My anvil is close to an overhead door, so the coal forge can be outside. When I’m done forging, I just shut the air down, separate the coal, let it cool for just a few minutes and wheel it inside.

I like it better than the propane forge that cost almost 10 times as much and took a bunch more work to build. The propane is noisier, and try making a dinner bell in it! All in all however, I’m glad I now have both. If I get the urge to forge in bad weather I can use propane.

My only supply of coal I can find local is Tractor Supply. They have Nut coal and Rice coal. I started with the Nut Coal. It was near impossible to get started and keep burning. I tried the Rice Coal and that was much better. In trying to just use up the bag of Nut Coal I found that mixing the two worked best. Both of these coals are anthracite coal. I hope to find Bituminous coal, which is softer and works much better (so I’ve heard).

My air flow is a broken vacuum cleaner. I removed all the unwanted parts from it and cobbed up an air hose. I do want to find a way to regulate the air flow.

The bottom of this forge is actually the top of the wood stove turned upside down. It just makes up the stand for the fire box section.

So here is a few things I’ve learned.

• The sides should be just high enough to stop the coal from falling off. If its to high it makes it hard to get the piece in the hot spot. The lower the sides, the more convenient it will be. If a table top was big enough to not need and side, that would be awesome.
• You don’t want the firebox to deep. I always wondered why some of the commercial made forges didn’t have a firebox at all. No firebox will work far better than a firebox to deep.
• How big the forge is isn’t of great importance,  you typically only work about 6″ or so of heated metal at a time. Support outside the forge can be helpful to help hold longer pieces however.
• Bituminous coal is blacksmith coal.
• If you are going to put a coal forge inside, think of it like a hood over a cook stove, not a chimney on a wood stove.
• I didn’t believe you could burn metal quicker in a coal forge than a propane forge. Believe it!

I ordered some 2″ black pipe fitting to get the air from under the fire. Getting the air under the fire seems to be the best way to go.

Here is all you need.

• 2″ Black Cap
• 2″ Black Floor Flange
• 2″ x 2-1/2″ Black Nipple
• 2″ x 4″ Black Nipple
• 2″ x 5″ Black Nipple
• 2″ Black Cast Iron Steam Tee

Think of how you will connect your air. You may want the side intake longer. I also reduced mine with a shop vac end.

I forgot to order the floor drain so I wound up making the screen section to keep the coal from falling down into the pipe.

Here are some of the “Not so good” ideas……….

To say this didn’t really work very well was a bit of an understatement. I still wanted to use this old wood stove, if for no other reason than pure stubbornness, but I also felt if modified correctly, it could work out well.

Next was to find a rotor. The best way to go about a forge is to have a fire basket. And I soon learned bigger isn’t necessarily better. This truck rotor is actually a little to big based on most opinions I’ve heard, but not really by much. I believe it would have worked, but I found one a little shallower and I went with that one.

The larger deeper rotor would have burnt more coal to get the fire high enough to use.

Here is the one I ended up using.

I started the transition by cutting the opening in the front. This was more or less a design on the fly kind of project, which is typically what my projects are anyhow. It wasn’t a good design for a forge. A fireplace maybe, but not a forge.

So lots of things wrong with this original design. But doing it all wrong taught me why what I ended with was right. Low sides, High fire hot spot, and lots of air.

And the first real projects from the finished product. Dinner Bells made from some 100 year old rod.

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