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Does cokeing coal, insulate and radiate heat? Or just radiate heat?
I've made some observations concerning fuel efficiency working with coal, coke, hard and soft firebricks.
What are your observations and opinions?

For instance, the color of the fire is an observation of something a little more complex.
UV, infrared reflection, and insulation are nothing new to gas forges, and the subject has been broached on solid fuels before. But coal is rather inexpensive compared to gas and much easier to get up to temperature so it doesn't seem to be a major concern for most folks. I imagine if there was something useful to know on the subject, it would be implemented in some sort of industrial setting, but Google has kinda let me down in such a quest for knowledge.. and to be honest my head already hurts and I need to go mindless hit something with a hammer to alleviate the swelling..
Thanks - Greg

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1: every thing insulates---some things just insulate very badly!

2: when coking coal you are driving off the volatiles and you WANT the volatiles to leave the area---unless you are doing this on an industrial scale in which case pollution control laws require you to capture and process the volatiles (and sell the byproducts!)

3: once the coal is coked---especially in a forge vs an industrial set up it is a better insulator---more porosity, it may even float on water!

Some smiths pre-coke coal for their use later in a different forge.

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That makes me appreciate my daily dose of labor a bit more Sweany. I'm darn spoiled. Folks doing all they can just to eat.

Yes Sir Mr Hale.
Here is my coal:
post-19492-0-95109100-1340889820_thumb.j
I've been able to find some good advice on coking the coal dust by making a slurry.

Here is my current favorite forge:
post-19492-0-58564100-1340889831_thumb.j

Coke fines and ash:
post-19492-0-75858000-1340889869_thumb.j
My question stems from trying to decide if I should install a air blast director/clinker breaker or just keep letting coke fines pile up with out knowing the most efficient way to use them. Right now I don't have a much of problem with clinker because of the size of my air inlet. I'd rather not do much more work than necessary, but a little work now to save some head ache in the future.. well that I don't mind.

On a somewhat related note.. As I was at the forge yesterday I attempted to see what effect letting the coal flame up freely outside of the hearth had on the atmosphere within the firepot. Something I've tried to note in the past but haven't drawn any definitive conclusions.. my assumptions tend to give me little faith in my own observations.. Trying to fully understand the anatomy of a fire is a step I want to have down before trying any more complex welds.
Any advice is helpful, because I probably don't even know what to ask - Thanks

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We get our coal as fines and store it in a bucket of water before use. The wet coal seems to hold together better as it's coking up to make chunks for forging with. I coke in my forge on an ongoing basis: start wood fire => add coke from previous fire => add wet coal around the perimeter and over the top as the coke fire gets established.

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can i ask you something?
by your experience and talking about efficiency, what are the best dimensions of the fire pot, or depends on the type of work you are doing, i mean, a blacksmith has two or three forges with different fire pot sizes or not?. I ask this cause im not completely happy with my forge.
regards.

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In general it depends on the type of work you are doing---welding up 1x1" x 6" billets is most efficiently done in a different sized firepot than working 2" round stock which is different than working 1/4" sq stock, etc. When I teach pattern welding I always have the students start with a billet sized for their forge so they can learn the process before they have to deal with multiple welding heats over a piece longer than their forge's hot spot for example.

Solid fuel is a bit more forgiving in that you can heap it high, blow it strongly and stick bigger things into the resultant hot spot. I've been known to take a pickaxe and dig a large trench forge in the back yard for certain projects or make a micro forge for others. You can also stack fire bricks to downsize the fire; but then have to be more careful about over blowing it.

Commercial firepots are a compromise and even then you could buy anything from a table top farriers forge that will fit entirely in a ruck sack to a "RR forge" 4' on a side with a firebrick lined bed. I've also read of 19th century shipbuilding where they would build a huge coke fire on the floor of the factory to heat up big chunks of iron they were going to weld together as part of the ship's frame.

So can you describe exactly what you are trying to do, with exactly what and how it seems to be failing in your opinion?

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Thank you sir for your answer.
My problem is that i made a new firepor for my forge with the measures i found in several web pages and forums. The top opening is 10"x8", and the bottom 6"x4", but the depth has been always my problem, i made a 4" depth but seems to much when i go advancing into the stock (towards my hand) because to heat the middle of the bar i´d have to fill all this volume and more so i can put this part of the stock in the coal. When i work in the begining it´s no problem because i just burry it in the pot.
I don´t know if i explain it well, my english is not too good.
Regards.

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Hi Yoncofi,
If I understand you correctly, you are using the firepot to heat your metal, to heat the centre of the metal you need to build the fire above the level of the top of the firepot to allow material to pass through the hot spot,

You may also have to increase your airblast if you build the fire above the top of the firepot.

As Thomas says there are many sizes of firepots for many varied work situations, it is my experience that people tend to make their firepots too deep, particularly if doing work along the length of the workpiece, shallow is good.

Another alternative may be to put another base into the firepot halving its depth.

Whatever you try, please keep us posted. Good luck with it.

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If the hot spot in your firepot is inside the pot then you need a smaller firepot or more coal and air blast to get the fire up over the top so you can stick steel in horizontally. In General you want a deep pile of coal so that all of the oxygen is consumed before it gets to the work. Many beginners work in a way too shallow fire.

At times people will bend a piece to get a certain area into the hot spot especially if the piece is odd shaped and large for the forge being used.

If you have access to firebrick you can try to place a layer of it in the bottom of your current firepot using wood ashes as a loose mortar and move your tuyere to the top of the layer of brick and see if that helps. If it does you may want to track down some fireclay and make the change permanent.

So far your English is fine; much better than my Spanish and German!

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Hi Yoncofi,
If I understand you correctly, you are using the firepot to heat your metal, to heat the centre of the metal you need to build the fire above the level of the top of the firepot to allow material to pass through the hot spot, You may also have to increase your airblast if you build the fire above the top of the firepot.


That´s right. The problem is that i´ve never seen a forge working besides mine, so i don´t know if it´s correct to go with coals above the top of the firepot when it´s too deep, and it will consume all of my limited reserves of coal.


As Thomas says there are many sizes of firepots for many varied work situations, it is my experience that people tend to make their firepots too deep, particularly if doing work along the length of the workpiece, shallow is good. Another alternative may be to put another base into the firepot halving its depth.


Ok, good to know that there are different sizes for different works.


If the hot spot in your firepot is inside the pot then you need a smaller firepot or more coal and air blast to get the fire up over the top so you can stick steel in horizontally. In General you want a deep pile of coal so that all of the oxygen is consumed before it gets to the work. Many beginners work in a way too shallow fire.


Deep pile for the oxigen to consume and horizontal, thanks to remember me this important things. As i said before, i made this new firepot from the information i gather, mainly from the firepots for sale in centaurforge i think, and other web pages.


At times people will bend a piece to get a certain area into the hot spot especially if the piece is odd shaped and large for the forge being used.


That´s what i tried to do with the last work i was practicing with, cutting and luckily it was bended before. I´ll try to attach a photo i went to take after your first response. I hope you can see it.


So far your English is fine; much better than my Spanish and German!


German... maybe like my japanese...!!

Thanks a lot.

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My project at work has both centers in Germany and in Chile; I can order a beer in either place!

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My project at work has both centers in Germany and in Chile; I can order a beer in either place!


and i will fill your glass if you come here.

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Where? (You might add your general location to your profile so if some smith closer stumbles across this site they can see that they should get in touch with you.)

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Would be great to be in presence of a real blacksmith. One of my dreams is to go to the US or Europe to participate in all the classes i could, regrettably for now i can´t.

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Would be great to be in presence of a real blacksmith. One of my dreams is to go to the US or Europe to participate in all the classes i could, regrettably for now i can´t.

You and I both, good luck!

Knowing now that coal isn't really necessary for any additional heat retention. I installed a small cross section to my tuyere and kept the fire going most of the day almost exclusively with the coke fines I sifted through from my ash dump. Worked out much better than I could have hoped with a little kindling mixed in when ever I was going to be away for a bit. I had a lot less trouble using only coked coal. Thanks for the help - Greg.

post-19492-0-35509000-1340994524_thumb.j

post-19492-0-08142700-1340994541_thumb.j

post-19492-0-68675000-1340994558_thumb.j

post-19492-0-57973500-1340994582_thumb.j

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My current job is software engineering for the ALMA project a large radio telescope being built near San Pedro de Atacama. Unfortunately my part of the project ends this year so I will not be making any more trips to Chile that I currently know about.

If we had known earlier I could have brought down a stack of blacksmithing books for you. I did collect some scrap metal from the construction site to be welded up for a memento blade. (And learned to appreciate Pisco Sours not to mention having avocado puree for breakfast...)

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You and I both, good luck!

Knowing now that coal isn't really necessary for any additional heat retention. I installed a small cross section to my tuyere and kept the fire going most of the day almost exclusively with the coke fines I sifted through from my ash dump. Worked out much better than I could have hoped with a little kindling mixed in when ever I was going to be away for a bit. I had a lot less trouble using only coked coal. Thanks for the help - Greg.


That´s a beautiful coal fire at your firepot, i´ve never managed to have one like this, the hot spot is always at middle depth and thats my problem i mentioned before. Do you know thw dimensions of yours?
And the trays below the forge are a great idea, i´ll copy (¿copiar?) your idea.



My current job is software engineering for the ALMA project a large radio telescope being built near San Pedro de Atacama. Unfortunately my part of the project ends this year so I will not be making any more trips to Chile that I currently know about.

If we had known earlier I could have brought down a stack of blacksmithing books for you. I did collect some scrap metal from the construction site to be welded up for a memento blade. (And learned to appreciate Pisco Sours not to mention having avocado puree for breakfast...)


Well, i hope some chilean guy screw up the system so they send you back here.
I have bought some books from ebay, including the 2 volumens of Mark Aspery´s books, and downloaded almost anything i found related to blacksmithing. But there is a little problem with my english, i don´t know some more specific words used in the books, or inclusively here at the forum that in spanish don´t have a literal translate and sometimes i cannot understand the idea and google isn´t realy effective with this terms. For example i don´t understand 100% what GregDP said above but i almost get the idea.

And yes, pisco sour is great, with half a bottle you are a happy guy, and the avocado is really great here. I think Chile exports both to US.



Best Regards.!

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