Round vs. Rectangluar Firepot

[VaughnT]

I honestly hate to ask a question that I'm sure has to be asked and answered a dozen times somewhere here on this board, but my searches haven't turned up anything.  So, for curiosity's sake.....

 

Why are coke firepots round and coal firepots rectangular?  Why the need to differentiate between the two?  If coke burns hotter and requires a thicker pot in order for the pot to last as long as a thinner coal pot, okay.  But is that really a concern?  Or, has it simply become a tradition?  

 

All of the commercially-available coke firepots are advertised as being greater in wall thickness than their coal-burning cousins, but the prices are relatively similar.  What happens if you use coal in a coke firepot?  Would this be similar to dividing by zero?  The end of the world as we know it?  Much crying and gnashing of teeth?

 

How many times can you work "gnashing" into a sentence on a blacksmithing forum!!!   B)

 

Curiosity's got me and I'm going to put something together just as soon as life settles down a bit.  Thanks.

[Dale M.]

I never quit equated  one forge shape to fuel type.... I equated it to type of work the was accomplished at forge.... Square fire pot for big heavy  massive objects the required lots of repetitive heating and round,  lighter one  for specifically like rivet work where it was more portable as work on bridge or skyscraper moved.......

 

Dale

[VaughnT]

Sounds reasonable, Dale, except for the fact that the round coke pots are generally thicker than the rectangular ones and would last longer in an industrial setting where heavy forging was going on.  Of course, we're talking about the actual pots themselves and not the shape of the whole forge.

 

I'm trying to figure out what benefit there is to using a round (actually hemispherical) fire pot with coke when both styles do the same basic job of focusing the fuel above the air source.  Both hemispherical and inverted/truncated pyramid type pots would seem to burn through at the same given rate because they're made of the same material, roughly, so why use/advertise one shape for one fuel and another shape for another fuel?

[MLMartin]

I do not believe the shape affects the fire in any way other than the shape of the fire! Many people use round pots for coal and many people burn coke in square pots. Fire pot depth is important for the type of fuel. More people tend to use a deeper pots for coal than coke. A shallow pot with coal will produce a oxidizing fire. I am sure you could build a tear drop shaped pot and have a funny shaped fire and it would still be just fine. Shape is just shape.

[Dale M.]

My observation is with my home made forge (brake drum style), is the fire ball is above the  air inlet and the unburned coal and finds seem to form a  beveled or cone shape from center to outer lip.... IF this holds true with square fire pots, it would seem to me  the round or  square fire pot argument/discussion in moot and its where the fireball places itself and not shape of fire pot or fuel used, except in case of long narrow firepot used for sword making,  after all is it not ultimately the burn of coal to get it to reach coke stage where it seems the ultimate heat is...

 

Whether fire pot is square or round does not seem to matter as long as fireball (shape)  is appropriate for item(s) you are heating....

Dale

[Herb Upham]

My experience is that the round coke "fire bowls" are more resistant to cracks than are the rectangular. Coke fires tend to transfer more heat to the fire pot than coal and cause more heat stress ... the round style heats more evenly and should be less prone to cracks. My round one is also thicker than most retangulare fire pots which helps as well.

There is very little difference in actually working out of either shape ... the depth of the fire is what matters most.

[Adam C. ToolSmith]

would that then mean that a side blast forge is better in that sense 
 
Herb 
Because a side blast forge has no firepot so to speak.

[Joel OF]

From my limited experience I can't find any difference. I used to use a brake drum forge before I fabricated a rectangular fire pot out of some RSJ...and shock horror...they both burn coke. Before I fabricated my own forge I too researched this question till I was blue in the face as I was determined there must be an answer but I couldn't find any answers so I just gave up and thought I'd get on with it.

 

To me this is a bit of a Pepsi vs Coca-Cola situation...they're virtually the same thing and serve the same purpose...and the people to gain the most out of telling you otherwise are the people trying to sell you one over the other.

 

I'm also using a hand cranked blower on my rectangular coke fire pot/forge and it all works fine. Before I got my hand cranked blower every thread I read about them said they can't run coal or coke forges...so if I was to believe the round vs rectangular fire pot argument + the hand cranked blower argument then I might as well given up blacksmithing and taken up knitting. Reminds me of an old Guinness advert: "80% of facts are false".