Anthracite Forge Cold Spot Help

[TimDorn]

Hello guys this is my first time ever writing a forum so go easy on me. However, after searching the internet for hours I cannot find a forum on my particular problem. I am running a homemade forge with a homemade fire pot and clinker breaker. Although I have burned bituminous before, it is hard to come by and I don't particularly care for how smoky and stinky it is! So after searching, I have found a local feed store that carries anthracite for a more than reasonable price of 5$ for 50lbs. I really like how hot and clean the anthracite burns and never seems to burn down as quickly as bituminous. However, I have a problem that occurs every time I run my Forge. It works beautifully for around an hour and I can easily reach welding heat, but after this first hour it is like a light switch is flipped. I can see a bunch of unburned, black coal at the bottom of my firepot and the fire cools down considerably. After about five minutes, my coal bed looks like checkered black and white. If I scoop the cold coal out of the center, there just seems to be more coal around cooling and falling down. I don't understand what the problem is seeing how well it works in the beginning of my fire. Apparently this isn't a common problem as i cant find a forum on it anywhere. It is very frustrating and is ruingin the forging experience for me. Anything would help, and thank you all.

[Frosty]

Welcome aboard Tom, glad to have you. If you'll put your general location in the header you might be surprised how many of the iforge gang live within visiting distance.

It's clinker sucking the life out of your fire. Hook it out and rebuild the fire, it'll make good heat again. The probable reason it's $5/50lbs. is it's got a % of shaley coal and or oil shale in it. The stuff burns okay for a while but not well enough to forge with and the mineral residue welds itself together as clinker.

Frosty The Lucky.

[Kevin Olson]

Post some pics of the fire pot or at least give some dimensions and a discription. I have seen these little black un burning things too. It obviously is  un burnable fuel and waste (clinker) that's not going down the ash tube. At this point I pull the fire apart (moving very fast so it doesn't all stop burning) and scoop out the center of the pot and out towards the edges to get that very small like burning sand out then push it back together adding some coke and hit the air and hope it comes back to life. Almost all of the time this works and I get that super hot fire back

[TimDorn]

First off, thank you both for your quick response. I never would have guessed you guys would answer that fast. Im sorry I didn't respond sooner, but I have been busy all day. 

Anyway, I took some pictures of my firepot, sorry for the bad lighting. Its about 5 inches square and 2.75 inches deep. Im not sure exactly what angle the firepot is, but the second photo explains itself. I would guess around 110-120 degrees.

I imagine you two are right about the clinker as the heat decreases so much. Is there anything you guys think could be done as a preventive measure? It is quite frustrating to have to stop my fire after an hour every time. Thanks again for your hospitality and accepting me into the forum life.

 

[JHCC]

Preventative measures? No, it's the nature of the material: as noted above, it's the non-flammable mineral content melting together at the bottom of the forge. The only thing you can do is learn how to manage it. My own best results have come from hooking the clinker out before it gets too big to be a huge problem, and from building the fire up large enough that the removal of the clinker doesn't gut it entirely.

I disagree that it doesn't burn well enough to forge with (sorry, Frosty), just that you shouldn't expect it to burn like bituminous. 

[ThomasPowers]

Also the amount of non-burnable trash rock that finds it way into a bag of "coal" can vary greatly; especially if they are scraping the bottom of the bin so to speak.

[Nobody Special]

Clinker. You can forge with anthracite. It's a pain, but you can.

The big things are a. It takes a lot of air to light and to keep going. b. It's much more difficult to light. c. Clinker kills the fire fast. d. Because it uses more air, it usually burns much faster than bituminious, and hot. It's easy to burn up your work if you're not careful. You can't really turn the air down to allow slow soaks at lower temps with as much finesse. It also oxidizes the steel faster, more scale. e. It has a nasty tendency to go out the second the air is cut off. f. Some anthracite will spit chunks of coal at you as it heats up and splits. g. Since it doesn't coke, you can't build your little cavern for heating or welding.

You have several complaints about bituminous that sound like fire management issues. A well managed bituminous fire with metallurgical grade coal should be very clean, and have very little smoke, outside of the initial lighting, some of which can be avoided by using coke from the previous fire during lighting.  I would suspect that you are getting too much or too little air, and not allowing dampened coal to coke on the outside edges before moving to the center. I find it usually burns at maybe half the rate of anthracite, making it financially about the same if not cheaper to burn.

[Frosty]

Oh Anthracite burns plenty hot enough to forge with, I was referring to the oil & coal shale you often find in coal that hasn't been sorted and cleaned. The shales burn but not very hot and just make clinker. You can find the same stuff in bituminous too. It's just a matter of learning what it looks like and not putting it in the forge fire. Another facet of fire management is fuel selection and grading.

Frosty The Lucky.

[Bhutton]

Frosty...Can the shale sometimes look like thin barks of wood (Coal with rust staining)...Ive been burning some anthracite and noticed the thin shale goes straight to clinker. These are the rust colored pieces. Ive been tossing them out. I like bituminous much better. I think its a more consistent heat. That dang anthracite has temps that jump all over the place on me...Guess i should just probably leave the blower fan run continuously? No air = No heat

TimDorn...Ive encountered the same problems as you have...One thing im learning is fire management doesnt happen over night...Or at least in my case it doesnt...Bruce

[Lordhumongous]

Im also a new member and new to smithing. I fabricated a similar firepot and have had the exact same issue. Thats actually the reason i signed up! Coal and fire problems are taking a lot of the enjoyment out of smithing. Had been using tractor supply anthracite because i got it for $2 a #42 bag. Great/adequate for a hour then by the time i rake out the clinker, there isnt really a fire left. No coking that ive read about and tried to recreate at home. Recently found another source of coal at an agricultural supply. $12 for #100. It burns very dirty at first then cleans up some. Is this bituminous? Had my first signs of coking. Still haven't got to use much of it. Still struggling with it. I really just want to shape steel without fighting my fire all the time. Sorry if i highjacked this thread. Looking for help. Thanks guys

[Frosty]

I must have missed your question completely Bruce, sorry. I don't know what's going on with your coal except in broad terms. Coal is laid down in layers as the result of various kinds of plant life that lives, dies and gets covered before it can rot away. This is USUALLY in marshy conditions where the dead stuff is submerged in an anaerobic environment and lacking oxygen doesn't rot. Peat bogs are good examples of the right kind of environment and plants but there are all kinds of plants making up coal.

As it settles occasionally it got covered by silt, sand, mud, whatever and as layers built up it was compressed, cycled through the crust a little for a few tens, hundreds of millions or maybe a billion or two years and viola COAL! Ayup, just like THAT!

I can't say what was laid down with what's available to you for coal. But shale is pretty common stone to be interspersed with coal seams, it's the minerals that forms the parts of the geology that isn't coal. The older the deposits the stonier it will be, the Talkeetna deposits are from the Little Carbonaceous from around 75,000,000 YBP. and being darned recent formations has a lot of mudstone and siltstone layers.

One good indication as to how poorly qualified I deny I am to judge coal, especially from a verbal description online, I have probably half or more ton of coal I mined myself from a trench I know for a fact to have outstanding metallurgical coal that has been sitting there for probably 15+ years at least. I mine it from the good trench and CAREFULLY selected coal that makes clinker faster than a goose can eat a bug.

And for my next awe inspiring feat of blacksmitherlyness I'd like to say. . . .WELCOME ABOARD Lordhumongous, glad to have you! If you'll put your general location in the header you might be surprised how many of the Iforge gang live within visiting distance.

Now, even though I'm not a coal forge guy I CAN help with your issues to this point. First fire management is one of the trickier things to learn and it's ongoing with a solid fuel forge.

If there isn't any fire left when you rake the clinker out you're waiting too long to clean the fire. Clinker will fool you it looks hotter than heck, hotter than burning breeze in fact for a couple reasons: 1, The breeze (forge coke) is only really HOT on the side the air is coming from so what's in your line of sight is the cooler part. 2. Clinker absorbs heat and stores it because it's mineral rather than organic fuel so it gets just as hot as the hottest part of your fire. When the fuel is used up the clinker is exposed and looks like a REALLY hot fire rather than something to get rid of.

That's one reason fire management can be a learning curve that takes a while to climb. Different coal burns and leaves clinker at different rates so you have to learn to observe, note and adjust.

LIght your fire, I like making a coil of cardboard from a strip about 2" wide and 12+ long. lay it on the air grate, let it spring open slightly and surround it with coal. I put the coarser pieces directly against and over the coil, say about a 3lb. coffee can's worth. Then I pack wetted fines around and over the mound leaving a crater in the center to the coil. I light a stick match or two and drop them between the center of the coil it's usually open a little more than farther out. Give it a very gentle blast of air till the coil is lit then cover it with coarse coal. Okay, that's just how I light a coal fire, NOT how it's "supposed" to be done, right wrong or indifferent, it just works well for me.

When your coal gets burning the fire is blown through the pile the heat drives off the volatiles leaving breeze. Breeze is to coal what charcoal is to wood, relatively pure carbon. Breeze is different from commercial coke in that commercially the coal is ground and packed into steel chambers which are heated to drive off the volatiles, called Pyrolizing. The resulting coke is very dense, hard and a better fuel for commercial smelters, etc. It's much harder to light and keep lit for small scale operations like ours. Commercial coke is much more popular in Europe than America though we can often get it from oil refineries as a bye product of refining oil.

Glenn frequently posts an excellent cut away graphic of how a coal fire should look, what the zones are and where to place your stock.

It takes practice and the best way to learn good fire management is to hook up with an experienced blacksmith and get him/er to tell you what you're doing wrong, show you how they do it, etc. Make contact with your regional blacksmithing organization, attend meetings, join, meet the folks. You'll learn more in a couple hours with an experienced smith than you will in days trying to figure it out yourself. 

Frosty The Lucky.

[TimDorn]

Hey guys thanks for the great discussion. It has been a while since I last checked this forum.

Now that I've had time to play around with my forge, I can say 100% that the problem lies in the buildup of clinker. When I notice the fire reaches about peak performance and a bit of time has passed, I leave the air on, pull my work out of the fire, and then dig around, normally pulling out a few pieces of clinker the size of my palm. The fire dies a little bit after they are pulled out, but in a few minutes it's back to peak performance and won't die out. I can now keep a fire going until I go out, not the coal.

     So yeah, the anthracite is a lot more maintenance in my opinion, but it does burn very hot and clean once going. If anybody else has problems with the fire dying out, I would definitely check for clinker and go from there. Thanks everybody. 

 

[jlpservicesinc]

One of the best secrets to using anthracite is to keep the fire well banked..   A deeper fire bowl helps also..  While my experience is limited the stuff I did try and observed is.. 

Lots of fuel banked, lots of air..   Lots of fuel banked so when you clean out the clinker you have fuel just about ready to go.. 

Anthracite does not coke like soft coal.. It is hard and that's it.. Much more like commercial coke.. 

 

Welcome aboard. Guys