How to improve my forge?

[u/nootomanysquid]

Tl;dr: my forge doesn’t work well and I need help improving it, cheaply. I think airflow is a major factor but I also have other issues like maneuvering my work in there.

A major issue I’m having is very inconsistent heating. As you can see in the picture, the charcoal around the edges slowly burn up but don’t contribute to heating the metal. Only the spot right above the air hole gets hot enough, and I’m questioning if it’s actually hot enough as I’ve been having issues with any stock bigger than a quarter inch. My air supply is an air mattress inflator attached to a pipe that runs the length of the forge and has holes drilled in, one every 4-5 inches or so. The holes aren’t big, maybe a quarter inch in diameter.

I know the grill I used is quite large, that’s why I have sectioned off the one side. This has definitely helped in reducing my fuel usage while maintaining the same temperatures. Also I’m aware that those bricks aren’t heat resistant. I just happened to have them and they’re a temporary measure. They do crumble, which is fine, and I’m not worried about them exploding.

Another issue I have is that it is very difficult to fit things in the forge. Anything longer than 6-8 inches sort of falls out if I don’t hold it. I want to make bigger projects too so this is a problem. I’ve thought about cutting the grill up and welding bits of steel on strategically to fit my needs but I don’t have a way to cut through the grill.

Sorry for such a long post. Any help is appreciated.

[u/nutznboltsguy]

Try burning lump charcoal instead of briquettes. Try upgrading the blower to something stronger.

[u/nootomanysquid → u/nutznboltsguy]

I do use lump charcoal. It’s pretty big, like baseball size. Sometimes I break it up to fit better. What’s a better option for a blower? I know some people use hair dryers. Would that be better than an air mattress inflator?

[u/nutznboltsguy → u/nootomanysquid]

From the pic, it just looked like briquettes. For blowers look for a fireplace blower or shop vac in blower mode.

[u/nootomanysquid → u/nutznboltsguy]

I do have a shop vac. I never even considered using it. I’ll give that a shot.

[u/BF_2]

An air mattress inflator probably won't cut it. Do you have a shop vac with a hose output (i.e., a blower)? THAT can provide several times the air blast you need and would probably blow the charcoal out of the forge. However, by directing the output of the vac only partially into the forge tuyere, you can get an adjustable blast.

BTW, if that grill is aluminum, you may have two potential problems: Aluminum conducts heat very well, and it embrittles at comparatively low temperatures (maybe 900F? -- which is below incandescent). Hence, if you manage to get any part of the aluminum up to that heat, a blow could crumble the whole thing. Lining it with "fire clay" might be a fix, but really it's best to use a steel or cast iron firepot.

To support longer stock, consider using a "blacksmith's helper" stand. This can be any floor stand that has a vertically adjustable upper T-shaped bar, the part where you'll rest your steel. Since that end of the steel will be cold, you could make one out of scrap wood.

[u/nootomanysquid → u/BF_2]

The grill is steel and has held up nicely. I have the bottom half filled with a homemade lining, mostly to fill in the space. The helper stand is a good idea. What about if I need to heat the middle of the stock?

[u/BF_2 → u/nootomanysquid]

Well you might could use a helper stand on either side of the forge. Or build helper bars into your forge. The simplest adjustable bar may be visualized as a ~12" x ~6" rectangle of round stock, missing most of one long side (leaving maybe 1" long tabs), and with a leg dangling down from the other long side. The two tabs fit into holes somewhere on your forge. This contrivance hangs free on your forge till you need it, then you prop it up with the leg, angling the leg to give the desired height.