How to light a coal fire.

I’ve tried a lot of methods to start a fire, my favoured is simply a sheet of news paper and charcoal. They produce a clean fire quickly. Everything should be self explanatory, except perhaps F: drier lint is useful, but smelly if you happen to have a hairy family =P: A wind and sun screen is useful when the fire is in it’s infancy.
Here you can see a close up of coal, coke, and charcoal respectively.
N: When using an electric blower controlling the air flow can be done in many ways. I use a shop vac directed to a T fitting. On the side of the fitting, opposite from the opening and going toward the forge, I’ve fitted a ball valve to allow excess air to be channelled to a side draft style hood/chimney.
O: Additional air can be vented from the ash dump as well by sliding it open a bit.
Before a new day’s hearth can be lit: sifting the ashes must be done, removing occasional bits of clinker. I toss the coke into one bucket and more questionable sifted shovels go into a bucket of water. The coke floats, and the ash clinker and coal sinks.
First a ring of coke is made at the bottom of the firepot. Some charcoal is present.
A little more charcoal is added. Charcoal or dried wood tender will ignite much easier than coke. If wood is used do so sparingly. I don’t know that you can’t weld in a fire with burning wood, but I do know it takes up hearth space and doesn’t burn as hot as the coked coal will.
A single sheet of newspaper is lit and placed in the center of the hearth.
Many people will use lots of paper or ball up coke/coal fines into the paper. I’ve tried many methods; this is what works for me. Although a separate wood fire is always nice to steal burning coals from.
Some larger chunks of charcoal are quickly added while the air supply is on very low.
I would use less kindling, just enough to catch fire before the paper burns out.
The kindling or charcoal only need to burn long enough for the coke to catch.
The key at this point is not suffocating the fire. The blower is still on but you may find too much air causes smouldering kindling that won’t catch. Once again charcoal or even charred wood is much more forgiving.
This bamboo charcoal burns hot but quickly. I use it to supplement my coal more than primary forging, so I added more than necessary.
Some coked coal is added.
When you are sure the coke has caught pile more on. The blower is blowing lightly. If you used kindling you can even carefully pull out the burning wood and seal it in an airtight container, or extinguish it some other way. This will make for an easier fire next time.
Remember that floating coke, now is a perfect time to layer it on. This will buy the coal a little time to cook. You may increase the air some, but you don’t need a lot of air yet. Just enough to keep things going.
Pile your wet coal around the center of the hearth/firepot. I snapped this picture right after the wet coke lit, just before cutting the blower off.
A handful of mostly uncoked coal (from the bottom of the water bucket) was then placed on top.
Then a small scoop of wet coal was added. (This picture didn’t turn out well and I failed to notice at the time.)
The coal has heated up around the hearth and begun to melt and stick together as it’s coking. You can make a small entrance with your rake. Within this cave you’ll be able to keep an eye on your steel and see the color of it while still surrounding it with heat from almost every direction. The fire pot is 3 inches deep and the mound is about 5-6 inches above the forge table.
Note – the fire is about at welding temperature.
This is the fire after welding. You can see it’s beginning to burn hollow– there isn’t enough burning coke inside the cave. While enough fuel is present inside this cave to work, use less air and water to allow coking to catch up.
A hollow fire is a result of not enough coal coking because you’re keeping it too wet, or too much air being introduced. Too much air and not enough burning coke will cool your fire and create scale.
I use a ladle that’s easily held with my tongs to avoid steam. I can’t tell you when exactly you need to sprinkle the fire and surrounding coal with water, but the idea is to keep the fire from migrating out of the firepot (generally whenever you see large sooty flames). If the perimeter of the firepot becomes well coked it may need to be watered until it’s time to be slid inwards. Occasionally, after the blower is stopped, the coking coal atop the fire will ignite and go out as soon as the blower is cut on again. That is often a good sign to add more coal. I believe it also means the burning coke just below the top of the mound is consuming excess atmosphere from around the fire.
This post is about building and maintaining a coal fire. Forging completely with coke is an entirely different animal.
Heat cokes coal. Coal will burn, and it’ll stay aflame simply from atmospheric air. Coke needs more air introduced or blown towards it to stay lit. I know of no reason to burn coal other than to create a supply of coke and help maintain the shape of certain types of fire.
It’s time to sprinkle some water on the fire.
Time to add more fuel.
If heat becomes a problem then clinker build up could be the source. Clinker can be prevented from blocking the air orifice by firepot design, installed clinker breakers or simply by pulling it all out in one large sticky clump with your fire rake.
To the left you can see clinker and flux from lots of welding. The middle and right are two different types of clinker from seperate coal sources.

I’ve found this sort of fire useful to heat several inches of steel. In this particular fire I forge welded a small hook out of 6 inches of half-inch square. Then finished working out the edge of a knife with a seven-inch blade.
I use many different types of fires and I am by no means an expert. Working odd bends and unusual shape or sizes without destroying a coal fire is difficult for me. It’s easier when extra coked coal is on hand, but coke still has to be raked back or added. Time must be spent waiting for the fire to get back up to temperature once burning coke is displaced. Proper fire management is one of the most basic skills anyone wanting to learn blacksmithing should know. I’ve had to teach myself most of these skills but I’ve by no means done it without the advice of others. I’ve not seen a good step-by-step pictorial on the subject so hopefully some may find this helpful. I plan to post a similar post over at Iforgeiron.com. It has been asked about an awful lot lately and I know many people like me are unable to attend classes. Around here, even at the events I’ve been able to attend, gas forges have been prominent or coal fires were started early and maintained irregularly and without discussion.

8 thoughts on “How to light a coal fire.

  1. Nice job on the tutorial. I find that most smiths have a way of starting their fires that works well for them, so I am not sure there is a ‘right’ or ‘wrong’ way. I use a balled up piece of newspaper similar to what you mention and have always had good success with that. The important thing is getting a good, clean fire going without having to struggle. I have seen folks attempt over and over to replicate a specific set of instructions and fail, it’s when they go with their gut and ‘wing it’ that they find their own way.

    As for maintaining a good fire, that is a good subject for discussion. Again, I have seen many ways of handling a fire. I find the key is to keep enough fuel on hand and feed your fire often. Another helpful tip is to use the clinker breaker, this is the one thing I routinely forget and it really is necessary to keep oxygen moving into the fire.

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    1. Clinker! Thanks I completely forgot to mention how to keep an eye on clinker between resizing and labelling all the photos I never ran into a visual reminder. I really wanted to make the point clear that an awful lot of coal in and around the forge is a good thing. And how I’ve found water useful. I don’t use as much water when working with just coke. The rake does a good job keeping the fire contained. I’m hoping once I get these photo’s re sized some other voices of experience will chime in over at Iforgeiron. I don’t expect most working smiths to take the time to document something so mundane. But to me, as a student (class of the internet) I take pictures of so much already. Peer review is important to me. Something I don’t have the luxury of is working with experienced smiths often. Posting stuff is my best hope to correct those mistakes I may not know I’m making. Alas blacksmithing is my baby and I’m afraid she’ll grow up before my eyes and I’ll miss it one day if I can’t look back and say “remember when?” As always, thanks for reading and even more so for the reminder.

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  2. I actually mentioned to Brian Brazeal and his wife when I saw them recently that it would be really helpful if Brian would do a video on how he builds and maintains his fire. I find that most teachers or master smiths tend to gloss over this information as if you will somehow figure out how to master the proper techniques on your own. Fire tending is critical, I think, to producing high quality work. If you are unsure of how to produce a hot, clean fire, how can you produce a high quality weld, for instance. I always observe any smith I visit who uses a coal forge to see how they work their fire. I also ask questions if I don’t see a reason for something they do, I am naturally curious and never hesitate to be a pain in the butt this way.

    At some point I will do a similar tutorial for how I start my fires, then we can look at the differences between the two. I find that comparisons are very useful for improving efficiency in my work flow.

    Keep up the good work, I always enjoy checking out what you have gotten up to at the forge. : )

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