brother terry

What am I seeing in the fire?

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I really need to know what I'm seeing in my fire when I'm heating steel. How do I Know what"s coke or a clinker? I stir up the fire to get things hot and find what looks like bubblegum. It's white hot and sticky. If I put my steel in it to get it to welding temperature it Gets hot but never hot enough to weld. I've watched a lot of videos and they all talk about coke and clickers but nobody points out what they look like. I can pound steel and shape it but welding is just out of reach. Made a pair of tongs with charcoal that I made myself and they work but they aren't pretty just usable. The demos I saw never told me to make two pieces at the same time doing each step on each piece so obviously they don't mach very well. I read a post that one of you guys posted and it was big help, but I still don't know what I'm seeing. I've Burned up about 60# of coal so far and I've got three tools so far. Persistence is my middle name. I'm in conquer mode. I'd appreciate any understanding you guys can give me. 

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hmm.. hopefully someone has some good info for ya. i've been forging just long enough to know how my fire is acting to know if i have clinkers or not, and what they look like when i rake the coals to be able to pull it out. some suggest a convex air grate will make the clinker form around it like a doughnut. i havnt tried it yet but i am planning on it. visually clinkers usually look more porous to me like volcanic rock. though coal (bituminous that i use) can almost feel sticky when coking, the Hot clinkers feel almost like bubble gum with the fire tool. i can usually pick the clumps out without issue, and the fire roars back up getting some surrounding coking/coked coal back on it. hope this is at all helpful. if you dont get any better answers i can Try to get pictures tomorrow evening when i'm forging to show the clinkers better.

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Clinker is the impurities in the coal. Let the fire idle for a minute or so, with no air blast, and with a hooked tool of some nature, reach down and see if there is a lump or ring of material near or around the air inlet. Hook or remove this from the forge and then rake the coke and coal into the forge and add air to bring the fire back to life.

Study the clinker when it has cooled and with the soft coal we use, it will appear grayish and like burned rock, sometimes glassy. If you lightly hit it with a piece of metal it can have a clink sound much different from the sound made when you hit coal or coke the same way.

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Thanks Daswulf, Yes that does help. A lot. When i pulled this stuff up and on top of my flat stock, it cooled and turned into what looks like lava rock. Started pulling the stuff out and had more than i had coke and coal in the fire. I think I'll start with a clean forge. I use Charcoal that i made from oak to get my fire a good start, pushing the coal close to it to coke up. Hopefully when i go out there today i can get welding heat. 

Yes KRS, I've seen that sight. He's an amazing young man. I've watched a lot of his videos along with many others from other craftsmen. The videos don't actually show someone pulling out hot clinker, but thanks for the input. 

Thanks Glen, the stuff that i pulled out yesterday and cooled was brown and bubbly, like lava rock that i used to use way back when i was a landscaper. Now i know what to look for. I do appreciate this sight. I've learned a lot from just reading what you guys have to say. I wish there were some blacksmiths up in the northwoods of Wisconsin that i could visit and see what they are doing. A few farriers and a guy who seems real busy with work he does all over the country. I'm not really interested in shoeing horses so that's out. 

Thanks again guys for taking the time to answer my questions. I've got three kids that want to learn the trade and they are looking to learn from me so i've got my work cut out. My youngest is 27. Not such a kid anymore but when you're 67 anybody under 40 seems like a kid. Lol.

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brother terry,

check the list of associations at the end of the forums page. there should be something listed for northern wisc. . there are several members of this website that are in wisc and they may be able to help you. dont totally discount the farriers, they move steel when its hot also, you dont have to learn how to shoe a horse.

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One thing that doesn't get mentioned much is that it's possible to over-blow a coal forge.  I had occasions where I was trying to speed things up by working the bellows or blower harder.  Despite the higher airflow the fire didn't get much hotter.  Last summer I had a smith over who explained that a more gradual approach spread the fire to more coals which created more heat.  Slower airflow creates fewer clinkers too.

 

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Little late but here are some pictures I got last night.  Hopefully they can be of some value as seeing is sometimes easier to understand. Tho I could not get a quality picture of clinkers IN the fire as my phone just glares the light brighter then I see it. I tried a #5 lenses in front of the photo lense but it didn't seem to work well.

Warning, it's not good to stare into the fire too much as it can be bad on your eyes. That's covered in another thread by others  

 I can tell when I'm not the heat and I have clinkers built up.  Clinkers Do glow red like the coal when they are being heated by the coal but are absorbing your heat and not producing it. Once pulled out they will cool fairly quick. 

Most of the time while forging I can just poke at the fire and pick some clinkers out while it's going. If you've been forging and you plan to weld it probably is a good idea to clean out your fire pot and get a clean fire going as Glenn stated.

   To me it seems that different types of coal can make different types of clinker.  Some more dense then others, or maybe as rockstar mentioned it could be the amount of air blast and heat. 

Generaly they are like lava rock or almost dirty melted glass at times. 

In some pictures you can see when they cool they are more yellow-ish bit not always. 

4th picture shows some smaller ones on my anvil. 

5th and 6th pictures show some big ones I pulled out after some longer forging without picking at the fire too much. 

Last pic is just a bucket I keep in front of my setup to knock clinkers into when I clean em out. Not perfect but it works for me and I can toss coke or coal back into the fire that I accidentally knocked in there after It cools. 

Hopefully im not too far off base, this is from my experiences.  I am just a hobbyist, not a pro. Just trying to toss some visuals in the mix for reference. 

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Thanks Daswulf, now I know what a clinker looks like. I don't see a problem with your pictures, they are very clear. And I am not going attribute the clear pictures to my recent cataract surgery.:lol:

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On January 23, 2016 at 1:07 AM, brother terry said:

I really need to know what I'm seeing in my fire when I'm heating steel. How do I Know what"s coke or a clinker? I stir up the fire to get things hot and find what looks like bubblegum. It's white hot and sticky. If I put my steel in it to get it to welding....

Not sure wat u mean to "stir up the fire".   Not sure u wanna stir.  Depends on wat u mean by stir.  

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30 minutes ago, Bud in PA said:

Thanks Daswulf, now I know what a clinker looks like. I don't see a problem with your pictures, they are very clear. And I am not going attribute the clear pictures to my recent cataract surgery.:lol:

Lol no Bud, the pictures are clear, just that I was trying some pictures to show the clinkers as they are in the fire pot. Those ones just showed the overall glow of the fire. :)

 

image.jpg

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If I understand what he is saying (grin) Stir the fire would mean bring the clinker from the bottom of the fire pot to where it could be seen and removed.

If you are unsure what clicker is or what clinker looks like, take a double handful of dirt and throw it on the fire, Add air and heat and you WILL get clinker in short order. Dig it out of the fire and then continue to forge.

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I just watched the TJoe video that KRS above suggested.  I hope me typing TJoe is not offensive to TechnicusJoe.   Been a fan of his for some time.  Looks like he's not 16 any more!!   When I first got my first coal forge I had many of the same questions that this post discusses.  I think Tjoe answers many but you need to listen close for many hints.   It's a lengthy video but it also does not skip over all sorts of steps like so many videos do.   I like that he shows how long it can take to heat things up.  Great vid!  Awesome and thank you TechnicusJoe!   

Like I said above.  I did not see much "stirring" going on.

Tjoe is like TRex.   in my mind....    

the french version might not be so flattering tho...

 

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I agree Borntoolate, ThechnicusJoe has very good and helpful videos and the one on fire management was very helpful. 

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Hello everyone. Im looking for some help as a complete newbie here. Are these clinkers? They seem to be exactly what  you guys are describing. Im just startin gwith coal now, (before i burnt wood or charcoal), and this is what happened after my first day. How can i avoid these? how can i deal with them? All help is appreciated.IMG_0971.thumb.JPG.62a878c210d5fa6391be2

I had like 10 onese this size, and a bunch of little ones left. Are they a problem when they are this little, V V V?IMG_0970.thumb.JPG.1ee9d32a50f20292a75c5

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Yup it's clinker. You can't avoid it in a coal forge. You learn to deal with it. It's no biggy, pick em out and forge on. It happens. 

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When they get real big, they need a name!! You don't have to register them to get a Birth Certificate, though.

Some names are OK to say in public, some are not.

Neil

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SO how exactly do i tell they are there? and how do i get rid of them without turning it all off and waiting for the coal to cool to pick them out? I know its been said before, and I've looked at it, but i still don't reallly understand. Is it just something that you have to learn from experience?

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You'll notice that the fire is cooler than it should be and if you place a piece of stock in the bed it will feel... different. I'm not sure how to describe the difference but once it registers you will know. The big ones can usually be hooked and pulled out fairly easily. If they break on the way out a pair of narrow tongs comes in handy to grab the small ones. Killing the air for a minute or so helps too. When clinker is screaming hot I find it breaks more easily.

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Experience always helps. You can assume they are there if your fire isn't getting as hot as it should for the air your feeding it. Not too much you need to do about the small ones pretty much, just rake in some coal from around the fire. Poking into the fire I can usually feel the big ones. The small ones like you showed don't give me much trouble until they become numerous . those and ash usually fall down the grate or off to the side while I'm working the fire, or I see em and pick em out with my fire tool.

The video that KRS mentioned is a good one to start with. 

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Clinker material generally congeals into more-or-less a single lump. So, like jumbojak, I let my fire idle (no blower) for a couple of minutes so that it solidifies and then dig it out with my rake. It generally stays together or breaks into just two or three pieces. You'll need to do this once an hour or so. How often depends on your coal and usage. If I wait too long, I end up pulling out a piece that is virtually a casting of the bottom of my firepot.

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You guys were right, a bit of experience really helps. I went out and forged  a couple days ago, and now that i know what I'm looking for, was able to find the clinkers and pull them out. thanks for the help.

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Thanks from a real newbe.  Got the break drum forge together a couple of weeks ago and from what I have read the last couple of nights, have done about everything wrong!  Thanks to all for answering newbe questions.  My next pair of tongs WILL be better.

Papy

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Here's a big ol' clinker, fresh from the fire:

IMG_20160319_194726591.jpg

And cooled:

IMG_20160319_203807784.jpg

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