Clinker's

[eproberts]

I'm new to blacksmithing and need help with fire. i may have bad coal. What i thought was coal turning to coke wont burn right. No heat,I thought it may be what is called clinker but i'm not sure. It looks like lava rock.

[Don A]

The "lava rock" is coke.

With a deep pot full of coke and a decent air supply, you should get plent of heat, unless the coal happened to be extremely poor in quality.

Clinker, when it cools, will look almost like brown glass or baked brown clay with air bubbles and all sorts of cruddy looking bits scattered through it.
If the firepot is undisturbed, it will usually be centered around the air inlet.

Remember... deep fire, gentle with the air, and be patient.

Too shallow with the fire and too fast with the air blast and you'll just be consuming fuel, not heating iron.

What type of forge and blower are you using?

Don

[CurlyGeorge]

Yep. If it looks like lava rock, and is super light weight, compared to coal, it's coke. The clincker will look darker than the surounding fire, down in the fire. Welcome to IFI. It's really a great site. Come in and join the party any time.

[JerryCarroll]

There's some pictures of clinkers on here somewhere---use the search to look.