Category: Fire Lab

Fire Lab 03 – How to Make Your Own Char Cloth


Today in the Fire Lab we’ll be showing you how to make char-cloth using radiant heat in relatively airtight chambers.

Our first reaction will be on a 2000W digital single induction hob. Its radiant heat zone is wide and shallow by design, and so I am using wide and shallow reaction chambers, also known as tobacco tins.

Fire involves two stages, pyrolysis – where molecules break down under heat – and oxidisation, where carbon meets with oxygen. Here, we ONLY WANT PYROLYSIS.
We prevent oxidisation by keeping oxygen out of our chambers with the miracle of LIDS. The holes in the top are there ONLY so gas under pressure can escape, and those lids will flip right off if we do not use my secret ingredient: a brick

Today, we can tell exactly when I’ve switched my hob on and gone past the point of no return, because that’s exactly when it starts to rain, but the real indicator of success is white smoke pouring out of those holes, and – you will note – out of any other opening it can find.
This is why we use the term ‘relatively airtight chambers’ today. Some oxygen may get in, and some solid carbon may escape suspended in the smoke you see here, but for the most part, everything in our wood and cotton samples that is not carbon is going up and out of the tin, or making a messy resin mess at the rim of any opening.

Because this hob does not offer the same intense heat as a bed of coals, the whole process can take up to 45 minutes, and THEN you have to let everything cool down, including the brick on top, which will get very hot indeed.

But by the time the brick is cool enough to touch, the tins are ready to open and what you SHOULD see is charcoal more or less in the same shape as the wooden or cotton objects that we put in the chamber.

If you see any colour other than black, or if you open the tin and the contents smell acrid, liked burned toast or worse, then the organic molecules have NOT finished breaking down yet, and the evidence is right under your nose.

Also note THIS area right here underneath our vent, where the presence of ASH indicates that a small amount of oxygen has sneaked in during the reaction, causing a further loss of carbon.

For our main reaction today, we are going to use a bed of hot coals, which means setting a fire and waiting for it to mature, and when it does, we will have a radiant heat zone that is hotter AND goes higher, meaning that we can use larger tins.

I’m using travel sweet tins this time: they’re cheap, deeper, and they have snug lids. Note the holes I’ve punched in the lids using the tip of a thick carpentry nail or an awl. Also note the smaller upholstery nails pictured here that look like thumb tacks, but with longer shafts. We’ll be using them to ensure that gas goes out of our vents, but not back in.
Let’s get back to our bed of hot coals, introduce our reaction chambers to the heat, and get some stones on top to prevent our lids from flying off. Do note that in this case the reaction starts almost immediately, and please also take a moment to enjoy the sound of my vents tip-tap-tipetty-tapping.

15 minutes later, the reaction appears to have completed, but rather than waiting for the coals to cool down, we’ll use tongs to remove our chambers from the heat.

Once the tins are cool enough to handle, it’s time to take the lids off an inspect our work. You may note that if gas and resin have been forced out of the sides, then the tops may be a bit sticky.

Inside you will see we’ve arrived at the same result, only faster, and because we’ve taken the precaution of adding a one-way vent cover that lets gas out but not in, we’ve pevented oxygen from creeping in and have NO ash under our vents, and no wasted carbon.

Anyway, that’s how we MAKE char cloth, but stay tuned for our next episode where we will looking at HOW IT IS USED in fire lighting AND comparing the perfomance of char-cloth from different sources. Not all cotton is pure cotton, and polyester is the pits.
Stay tuned, and by that I mean please Subscribe.
Thanks for joining me in my enthusiasm for fire.
Cheers all.

Fire Lab

Fire Lab 01: Breaking Hearts & Bermuda Triangles


Today in the Fire Lab we’ll be testing two new products from Fire Burn Good: Breaking Hearts and Bermuda Triangles. Here’s our standard firelighter for reference. Opens from the top, lights with a spark and burns for 5 minutes to produce a hot coal that lasts even longer.
Our new 2-in-1 and 3-in-1 firelighters are equally water resistant, but you pull them apart to open them. revealing the soft cotton centres. You still need to prime them by pulling some of that cotton out into a plume, but the results speak for themselves.

Pictured is our standard firelighter alongside some of our new Breaking Hearts and Bermuda Triangles.
All of our standard lighters have a single cotton ball in the centre that ignites and regulates combustion before becoming a hot coal, and you can see how we fit two cotton balls into every Breaking Heart and three into every Bermuda Triangle.

Breaking Hearts snap into two firelighters, and Bermuda Triangles can break into 3. Or, they can act just as effectively as one large and more powerful lighter. For now, we are going to take a single portion from each of these firelighters and ignite them side by side to see if they pass our main endurance test. We’re also going to find out which firelighter flames out first, so if you’re the betting type, bet now.

On your sparks, get set. Go.

Every firelighter we sell should offer a bare minimum of 5 minutes of hot flame, and that should include single portions from our new 2-in-1 and 3-in-1 range, thus the need for endurance tests like this one.

You’ll notice some slight pooling while the lighters burn in a standalone position on a cold steel plate. This is NOT an issue when they are used to start a reaction in a typical fireplace, as the heat from the combustion reactions they start will reflect back on the lighter making pyrolysis even more efficient and complete, but do note the vapour clouds right above these pools that show the wax fuel wicking its way to the main reaction and the flames above.

We’re back at normal speed after 5 minutes, and all of our firelighters have passed the main test. Those flames indicate a healthy pyrolysis reaction, and the moment they stop, you know you are left with oxidisation alone unless you can exploit the heat from your hot coal to ignite further fuel and keep full combustion going, and I am CALLING it on 1/2 of a Breaking Heart at 5 minutes and 24 seconds.

Sorry if you lost your shirt. Next time, read the stats.

Our next test is a performance test to see what damage we can do with an entire Bermuda Triangle. Today, instead of the usual kindling, we’re using lumber in the form of two short lengths of 38×63 CLS planed Timber.

Rough timber allows smaller slivers of wood to lead the reaction deeper into the grain, but the smooth, finished surfaces of this timber are harder for fire to penetrate. Also, as you can see, the flow of the main reaction is going directly across the grain of the wood, meaning that our reaction will have to work harder to carve the channels that are necessary for a healthy pyrolysis reaction.

Not that this is going to stop our Bermuda Triangle. After 4 minutes, we remove the firelighter and you can clearly see from the flames above our lumber that it has ignited a self-sustaining reaction, and when we seperate the timbers, you can see combustion has been so complete at the centre of the fire that is has already produced ash.
Let’s lay that lumber out again and admire the channels carved against the grain by our firelighter to better enable efficient pyrolysis in the wood, and let’s also marvel at the fact that we not only have plenty of firelighter left, but it can still turn into 3 firelighters any time we care to separate the business, and it’s all down to the magic of those cotton ball centres.

This completes today’s test of Breaking Hearts and Bermuda Triangles. Thanks for joining me in my enthusiasm for fire.
You can buy all of these products on my website at, and If you’d like to suggest a challenge for our firelighters to test their unique abilities and upper limits , just let me know in the Comments below or get in touch via the Contact Form on our site.

Cheers all.

Fire Lab