Tuesday, April 27, 2010

Blacksmith Coal Forge Hood and Chimney

What do you need to take the coal smoke away from the forge when you build a coal forge?

I fire mostly propane so fume exhaust is a little bit less of a problem.
Coal forges definitely require a chimney to exhaust the smoke. There is a great deal of smoke
created when you burn coal.

Essentially you have two options
The first is the easiest and that is to make a large funnel shaped sheet metal hood to catch the smoke. It should enter into a 10 inch pipe (much smaller does not draft well for a coal forge. 8 inch diameter you take your chances on) This pipe should extend through your roof and ideally be 2 feet above the ridge line of the building. If you are in an area that requires building codes to be inforced you may have to use insulated stove pipe.

Coal smoke is actually much cooler than wood smoke and in reality does not need the insulated pipe but the building inspectors have no reference for this.
This hood works moderately well. You can start the draft by crumpling a couple of sheets of newspaper and lighting them on fire when you start the coal. Once the draft is started it is pretty easily maintained with the heat of the coal fire.
The second option is more complicated to construct. But works well. It is a Side draft chimney.
For plans google "side draft forge" or "side draft chimney for forge" you should be able to find something. It is basically a box that has a low opening in the side and a shelf inside the box that catches the smoke. The chimney draft sucks the smoke to the side and out of the way.

Good ones work very well. Again you may have to discuss chimney designs and materials with your building inspector.

Coal produces alot of smoke on start up, then simmers down as it converts to coke. Hardly any smoke with a coke fire. Charcoal works well too with very little smoke although you need some chimney to carry the fumes away from your work area.

I hope this helps. Good luck building your forge. Coal forge is the most versatile but it is a bit of a trick to get on to. It is also the easiest to build.

Take Care
David Robertson Artist Blacksmith