Air Requirements For Solid Fuels

[CrazySmithy]

Hello! So I am currently talking to some people about this in my other topic, but I figured it might be nice to just have a subject about it for beginners like me.

I am curious about how much air certain fuels need. I am using coal, but answers for coke and charcoal would be great to for others. 

For me, I don't believe I am getting enough air to my fire. I don't have any obstructions, maybe some clinker, but not enough to stop my fire from getting hot enough.

I am using either a small Chinese hand crank blower or a small squirrel cage blower. The fire would get hot, but it was small and it seemed like a lot of work to get it to get the whole fire hot. I had trouble heating up a 3/8" bar. 

I tired using a shop vac on the blow side, and it lit it up easily, though I had to restrict air flow a lot, and even when I was blowing as little air as possible, I think I was just burning through fuel.

So I think, I don't know, but I think I need a bigger blower then the small ones, and a smaller blower then the vaccum.

Also, my coal has been sitting outside for years, so it is quite crumbly which I am sure means something, I just don't know what.

And... I believe that's all my questions! Thanks for any help you give!

[ThomasPowers]

So you are using Bituminous coal and not anthracite?  (Crumbly usually means Bituminous). 

What size are the pieces? 

Is it known good smithing coal or just random coal?

Are you using a bottom blown forge or a side blown forge?

How it the tuyere configured?

Perhaps a picture of the forge and fuel in use?

So many details go into getting things just right.  However charcoal uses a more gentle blast have you tried it with that? (Charcoal, not briquettes!)

[CrazySmithy]

I'm not sure what kind of coal it is, and it's probably more likely just household coal, we got it when we helped a neighbor tear a shed down. The pieces are just random sized pieces, from pea sized to soft ball sized pieces.

It is a side blast forge, the tuyere is water cooled coming in at a slight angle, stopping at the edge of the brake drum I have in a 55 gallon barrel as a fire pot.

And I have not tried charcoal, I would, but I have tons of coal on hand and I'd rather use that first.

[Glenn]

Coal in this area ranges from 15,000 BTUs to low 13,000 BTUs. Below 13,000 is difficult to work with as there is a much lower heat from the fuel.  

They sometimes blend the fuels to match what BTU range or limits the customer specs out.  I have used some power plant coal and it is all over the place as forge fuel.  Sometimes there is lots of shale and rocks in the mix from where the top and bottom of the seam was scratched out while being mined.  House coal can be anything as long as it burns.

BP0131 Coal, Coke, and Rocks