coal size preference

[IRONMAN]

I have been using nut size coal for quite awhile but recently have started going to other meeting/demos and so far everyone has used stoker/pea coal.
When asked how they liked it compared to nut sized coal most said they didnt know because stoker/pea coal is all they have ever used.
SO
my question is
which do you prefer and more importantly why do you feel you get better results with your choice, or do you have a choice in the size or type of coal readily available to you.

[oakwoodforge]

Ironman, I don't use coal, I use charcoal so this may or may not help...
I chop/sort my charcoal in 2 sizes: 1 inch chunks for gerneral forging, and fingernail to pea sizes for forgewelding or heat treating. Up to a certain point I find that the finer stuff gives a more even heat and reduces de-carb & scale. Real large chunks of fuel in the fire seem to give me hot/ cold spots and scale problems.

Hope this helps,
Jens

[HWooldridge]

The only thing that burns on any solid fuel is the surface. Therefore, it makes sense that smaller sizes will yield more heat for a given volume of coal. In other words, throwing 4-5 fist sized chunks on the fire will not provide as much surface area as those same few pieces broken down to pea size. However, those large chunks will burn longer before they are consumed (same as firewood).

For years, I have used coal that was about 60% fines and the rest large chunks. This worked OK but I had to make a slurry and pack the mass into the fire so it would coke. Later on, I was able to get my hands on some that was about 95% in the size of 1"-2" with the rest being fines. This made a hotter fire and was easier to see into for both welding and general forging. However, it was not from the same mine so the major difference may have come mostly from the composition and less from the size.

[Ralph]

To me nut sized coal is still 'pea' sized. I like my coal to about the size of walnuts. less drops thru the clinkerbreaker/air inlet. I know that at Frank Turleys school part of the morning is spent breaking up the large coal into smaller useable coal. Each person does his/her own.

Ralph

[frogvalley]

Nut coal is best for me although larger chunks work fine for me too. About 20-30 percent fines mixed with it is OK. The bigger chunks break up easy enough once they are start to burn and are sprinkled and packed, as per the standard coking process of moving coal closer to the center of the fire. I have not recently tried to use finer coal, but I know many who do. I didn't like it as was stated, it tends to fall through the grate. And no I wouldn't like a smaller grate.:rolleyes: