Coal forge - better blower - how much improvement?

[Nihil]

Hello,

I built a coal forge based on Bob Patrick's firepot design and picked up what I knew would be an underpowered blower online for $15 just to get up and running.

With the blower running at 50% I get good heat that lets me forge nicely and can heat up a 6-8" bar of 1/2" to put some twists in.

At 100% I can get a pretty substantial mountain of fire and have made several welds of 1/4"-3/8" stock.

After forging a couple of hours I do need to fish out some clinkers but I knew going in as I didn't include a clinker breaker in the design (maybe for version 2.0).

My question is how much improvement will I see with a "true" blower?  Will it primarily be how much coal I can pile up and how large a hot spot I can make?  I have trouble imagining how much larger/hotter this size forge would be.  This is the first coal forge I've run so there limited experience.

Thanks for your thoughts!

[ThomasPowers]

Looks to me like it's running too high and not enough coal stacked up as it is.  Don't know how a bigger one will improve things.

Have you been to affiliate meetings and seen how other folks run their coal forges?

[TWISTEDWILLOW]

Your forge looks nice to me, maybe you just need to play with it a while an figure out what works with what you already got, 

ive forged over 1” stock in my little pancake forge that’s only 15” diameter and all that’s hooked up to it for an air supply is a little Buffalo bbq grill blower, 

[George N. M.]

The amount of orange and yellow flames suggests to me that you may be burning green coal rather than the coke which should be produced around the edge of the fire and then raked into the center to burn.  Coke does not produce such enthusiastic flames, even when there is a good blast of air going to the fire.  You can apply a bit of water around the edge of the fire (many folk use a sprinkler made of a can with holes in the bottom and with a handle attached) to keep the coking area darkened down.  Combustion outside the area actually heating the metal is just wasted fuel.

"By hammer and hand all arts do stand."

[Irondragon Forge ClayWorks]

Looks like your current blower is doing more than an adequate job. Like George N.M. said, learning fire control & maintenance will work better than increasing the air. Too much air is just as bad as too little.

[Nihil]

Quote

Have you been to affiliate meetings and seen how other folks run their coal forges?

I have not.  Its definitely on my list to make it to some so I can see how other people work.  I used a coal forge 5+ years ago but that was my 1st time forging ever so I was not paying close attention to the fire.

Quote

The amount of orange and yellow flames suggests to me that you may be burning green coal rather than the coke which should be produced around the edge of the fire and then raked into the center to burn.  Coke does not produce such enthusiastic flames, even when there is a good blast of air going to the fire.  You can apply a bit of water around the edge of the fire (many folk use a sprinkler made of a can with holes in the bottom and with a handle attached) to keep the coking area darkened down.  Combustion outside the area actually heating the metal is just wasted fuel.

That could have been the case.  I know as the day was winding down I needed to get a weld done and put a bunch of "new" coal on.  A sprinkler is a good idea as that might help the coke producing, I could also make more of a pile at the beginning of the day.

I find that the coal/coke around the edges/walls of the firepot sticks together and needs to be broken up to move it to the center.  I also find that I'll have a decent size cavity in the center, especially if I've not been actively mixing the fire.  Normal?

Thanks much for all the responses!  I'm sure experience will improve my outcomes, just wasn't sure how much was practice and how much was inferior infrastructure.

 

[ThomasPowers]

Yes, *good* coal cokes up into "chunks". 

Yes, the center of the fire burns out leaving a void. For open fire welding you can just pull coke in from the sides. For closed fire welding you can take your slice and shove it down along the sides breaking the coke up and driving it to the middle while maintaining the "cap" and following up by adding fresh coal where needed.

In general; for a coal fire you want to build it up towards the end of the day to make sure you have a goodly amount of coke ready to build the next fire!  Letting the fire burn down is a false economy as it makes the next fire take so much longer to get to using state.

[George N. M.]

Another thing to do, if it is available at an acceptable cost, is to start out burning coke rather than green coal.  I started doing that years ago to minimize smoke and smell to be considerate of the neighbors.  Even though I am now in a semi-rural area I still use coke.  It does take different fire management,  e.g., you have to keep at least some air to it or it goes out.  You can leave it long enough to go into the house to answer a call of nature or get a cold drink but that is about all.  And if you are doing bench work you have to turn around every minute or two and give the blower a couple turns.  If you are using an electric blower and you can set it low you are good but a hand crank blower takes attention.  It does give a much cleaner fire though.  You still get clinkers because the coking process does not drive off the non-volatiles like silica.

"By hammer and hand all arts do stand."