How to Make a Char Cloth: Instructions Plus Troubleshooting

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Any outdoors person knows the value of good tinder. Even with matches or a lighter, you won’t’ get a fire going without dry, combustible tinder.  Arguably, the very best tinder for firestarting is a char cloth.

Making a char cloth is fairly simple, but some issues can arise.

We’ll talk about how to make a char cloth and troubleshoot these issues here.

What Is a Char Cloth?

A char cloth is basically a cloth that has been turned into charcoal.  The char cloth ignites at low temperatures, which makes lighting it with sparks easier.

The scientific term for making char cloth is pyrolysis. You can read all about the science of it here. In layman’s terms, it involves heating a natural plant material in an anaerobic (without oxygen) environment.

You can often get a char cloth lit with just one spark!  You then use it to light other tinder. If you are trying to make a fire with a Ferro rod or flint and steel, a char cloth will make your life much easier – or possibly save your life in a survival situation.

*Realistically, you probably won’t be using a char cloth for survival.  I personally always bring a lighter and waterproof matches with me when I go backpacking in the wilderness.

However, it’s a lot of fun to build a fire using a char cloth and F&S (flint and steel).

DIY Instructions

To make a char cloth, you need to put a cloth made from natural material in a sealed, fireproof container.  You then put the container on a flames or coals.

Because the container is sealed, hot air inside the container will build up and exit the container.  Thus, the cloth gets heated in the absence of oxygen.

1. Get a Fireproof Tin

Tin for char cloth with cloth in it

Most people use an Altoids tin because they are so readily available.  You can also use things like soda cans with tinfoil on top to seal it.  Cookie tins or clean paint cans are good if you want to make larger amounts of char cloth at once.

Keep in mind that people have been making char cloth for centuries – long before Altoids was around.  The primitive way of charring a cloth involved wrapping plant materials in layers of green leaves.  The plant material could also be put in a clay pot which was buried in sand to cut off air.

Once you’ve mastered making a char cloth in a tin, it can be fun to experiment with making char cloths using primitive methods.

Tip:

When making large amounts of char cloth in larger tins, it helps to burn off any paint/residue on the tin first.  Otherwise you won’t know if the residue is making smoke or the cloth.

2. Punch a Small Hole in the Tin

The tin allows smoke to escape the tin while making the char cloth.  The hole needs to be small.  Just a pin hole will do! Nothing larger than 1/8th of an inch.

*Some people like to put a hole in the top and bottom of the tin. This allows gases to escape better when you flip it (step 7).

3. Get Your Cloth

It is imperative that you only use 100% natural plant-based cloth for making char cloth.  Any synthetics in your cloth will stop sparks dead in their tracks.  Wool also won’t work.  Below I’ll talk more about the best materials for char cloths.

I generally like to keep my cloths around 2×2 inches.  Some people get up to 4×4 inches.  The cloth will shrink a bit once it has been charred.

4. Put Cloth in the Tin

Whatever size you choose, don’t pack the cloth too tightly in the tin.  It needs to be loose or the cloth won’t char evenly.

5. Heat Your Tin

making a char cloth

You now need to close the tin and put it on a heat source. The easiest method is to put it on a portable camping stove.

However, it can be a bit tricky to see the smoke escaping the tin through the flames of a camping stove (which you need to see in order to know when the char cloth is done). It’s also hard to flip a hot tin on a camp stove.

A better method is to build a fire and let it burn down to hot coals.  Put the tin on the hot coals.  You can also put it directly on a campfire, but you’ll have the same issue as with a campfire – you won’t be able to see smoking escaping well.

6. Watch for Smoke Coming from the Tin

flame coming out of tin

Once your tin is on the fire, coals, or stove, it will cause the gases inside the tin to heat up.  This creates a higher pressure system and the gases will be pushed out of the tin through the hole you made.

Because the gases are escaping the tin, no air is allowed in.  This is imperative: if any oxygen gets into the tin, you won’t get char cloth!

As the gases escape, you will see smoke coming out of the hole in the tin.  Pay attention! You might also see a flame shooting out of the hinges of your tin as the gases ignite.

7. Flip the Tin

Once smoke/flame stops coming out of the hole, you will need to flip the tin over.  The reason for doing this is to make sure the cloth chars evenly.  Otherwise the bottom of the cloth gets more charred and the top is undercooked.

When you flip the tin, you’ll probably see more smoke or a flame start coming out of the tin again.  Once the smoke stops, remove the tin from the heat.

8. Remove the Tin from the Heat

It’s important that you remove the tin from the heat immediately after smoking has stopped (within 30 seconds of not seeing any more smoke).

If you let it remain on the heat, there won’t be any more gases escaping the tin – which means air can enter the tin.  Suddenly, your char cloth is exposed to oxygen and will be combusting instead of charring!

*When making char cloth on a bed of coals, it’s enough to just push it off to the side.  You don’t have to put it somewhere completely cool.

9. Plug the Hole

char cloth tin with hole plugged

A lot of people plug the hole of the tin once they’ve removed it from the heat. The reason for doing this is to prevent oxygen from entering the tin.

Air can come rushing into the tin as its cooling, potentially ruining the char cloth.  So, while not absolutely necessary, plugging the hole will usually get you more uniformly-charred, better results.

How do you plug the hole or holes in the tin? You can use the same pin or nail that you used to make the hole in the first place (though nails are a bit hard to keep upright in the tin).  Small sticks that have been whittled to a point usually work better.   I used a toothpick in this demonstration.

*Instead of plugging the hole, you can also bury the tin after removing it from the flames.

10. Let Tin Cool and Open

successful char cloth

Wait until the tin has cooled before you open it.  You should be able to handle it with your bare hands.

If you open it too early, oxygen can get to the cloth and cause it to combust.  While this has never happened to me, I’ve heard of entire pieces of cloth bursting into flames when the tin was opened too early!

Even if the cloth doesn’t burst into flames, the oxygen could cause some of the surface area to combust.  That limits the amount of useable char cloth you get – meaning that only parts of your char cloth will catch a spark.

Using a Char Cloth

a char cloth holding a spark

A char cloth will not make a flame.  Rather, it will catch a spark and make a small ember which slowly smolders. You can then use this ember to ignite tinder.  The tinder lights kindling which lights your fuel wood.  And then you’ve got a fire!

To make a fire with a char cloth:

  1. Prepare a “birds nest” of tinder. Read this post on the best tinder.
  2. Use your Ferro rod or F&S to rain sparks down on the char cloth. Read how to use a Ferro rod here.
  3. The char cloth should create a glowing ember.
  4. Put the glowing char cloth on your tinder nest.
  5. Blow so the char cloth ember transfers to the tinder and turns into a flame.
  6. Remove the char cloth and put it out so it can be used again.
  7. Keep feeding your flame and build yourself a fire!

Note that it can be hard to see the spark burning on the char cloth – especially in the bright sun.  You might feel it burning on your hand before you see it! 😮

Tips:

  • Test your char cloth! Before you take char cloth in the field, you should test it. You really don’t want to be in the wilderness when you discover that it has failed.
  • Practice makes perfect: Remember that matches and lighters were invented for a reason! If making a fire with a char cloth was easy, we’d still be doing it that way.  It takes some practice to get a fire going with a char cloth – especially when the conditions (wind, rain, wet tinder…) aren’t in your favor!

Troubleshooting and FAQs

Making a char cloth is a very easy process. However, don’t feel bad if you have some issues.  Here are some of the most common problems and questions people have with char cloths.

What should a char cloth look like?

When successfully made, a char cloth should be black all over. It should be soft, thin, and easy to tear.  It almost has a velvety feel to it, like old flannel.  You should be able to fold it and it will keep its shape.

If there are still BROWN parts on the cloth, it means that you didn’t cook the char cloth long enough.  This is no big deal.  Just restart the process with the same cloth.

The char cloth should NOT crumble or be ashy. It should not leave any soot on your fingers.  This means that you overcooked it.

What cloth is best for making char cloth?

Char cloth should be made from 100% natural plant materials.  100% cotton fabrics are most popular, but linen and jute also work well.  You can also use punk wood to make char cloth (though it won’t be a cloth).

Whatever material you use, it’s important that it doesn’t have any synthetics or wool in it.  It only takes a tiny bit of synthetic to stop a spark dead in its tracks!

Also make sure that there isn’t any fabric softener leftover in the material.

Some good options for char cloth material include:

  • 100% cotton Terry bath cloths (this is great because it has so much surface area!)
  • Old cotton t-shirts
  • Denim jeans (not the stretch kind)
  • Cheesecloth
  • Muslin
  • Canvas

Tip:

Char cloths made from thin materials (like t-shirts) ignite easier than those made from thicker materials (like denim).  The thinner material will burn faster, but it’s still better if you aren’t experienced using a F&S or Ferro rod.

How long should the char cloth cook?

It depends on how much cloth you are using and how tightly you packed it.  A loosely-packed Altoids tin will usually take 5-10 minutes on one side and 2-5 minutes on the other side.  Don’t go by these numbers though! You need to watch for the smoke to stop coming out.

Why isn’t my char cloth lighting?

There are several different reasons that your char cloth might not catch a spark and ignite. Here are some of the most common issues.

The wrong cloth was used.

Are you absolutely certain that the cloth was actually 100% cotton (or jute or linen)?  If there are any shiny areas in the cloth, that’s a sure sign of synthetics.

You overcooked the char cloth.

This is the most likely reason that the char cloth won’t light.  If it spent too much time on the fire (or oxygen got to the cloth after it was removed from the fire), oxygen will get inside the tin and cause the cloth to combust.

To fix this, remake the char cloth with fresh cloth.  This time, make sure you REMOVE THE TIN when the smoke stops and PLUG THE HOLE.  Don’t open the tin until it is COMPLETELY COOL.

If it’s still getting overcooked, you might have too much leakage in your tin. Make sure the tin seals tightly.

Remember, only uncombusted material will catch and hold a spark so you’ve got to make sure no oxygen gets to the cloth.

You undercooked the char cloth.

It’s easier to spot undercooked char cloth than overcooked char cloth. Undercooked char cloth will have brown spots on it.  These areas will not ignite or allow an ember to grow.

One reason for undercooking is that you packed the material too tightly. Try making it again but with less cloth in the tin.  You can also try flipping the tin around so the cloth inside gets more exposed to the heat.

The cloth got wet.

Even when properly made, char cloth will not catch a spark when it’s wet or damp.  The humidity from the air can enter the container you use to hold the char cloth.

If you are still at home, it’s easy to test whether this is the reason your char cloth isn’t igniting. Just put it in the oven at a very low heat for about 10-20 minutes.  This will dry out the char cloth so it can catch a spark.

If this doesn’t work, then one of the other reasons is probably to blame.

The fabric weave is too tight.

This probably isn’t the issue, but sometimes it’s hard to catch a spark if the char cloth was made from fabric with a tight weave.  You can try to fringe the edges of the char cloth to make them fluffier.

Flame retardants were added to the cloth.

Some shop cloths are treated to make them flame retardant.  I doubt that this is actually the problem, but it is possible.

Some of my char cloth batches turn out great.  Others barely catch a spark.  What’s the deal?

A lot of people will blame this on the type of cloth used. However, the real issue is probably that oxygen is getting to your char cloth, or to part of the cloth.

If even part of the cloth gets combusted instead of charred, it won’t hold a spark. So, you will be able to ignite parts of the cloth and the spark will just peter out as it reaches the combusted parts.

To get good, consistent results when making char cloth, you really need to PLUG THE HOLE.

Do I have to poke a hole in the tin to make char cloth?

No – it is possible to make a char cloth in a closed vessel.  However, it’s a lot harder to tell when it is done cooking.

Also, if you are using an Altoids tin and don’t poke a hole in it, the pressure from the hot gasses will cause the lid to pop open.  You could push the lid back down with a stick, but too much oxygen might have reached the cloth already.

How should I store my char cloth?

Keep your char cloth in an airtight tin.  The reason for this is to prevent moisture from reaching it.  Charred materials act like sponges and will absorb water from the air, making them difficult to ignite.

If you used a mint tin to make your char cloth, you can store it in the same tin.  Just use a piece of wax (from a melted candle) to plug the hole.


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    • One hole will usually be enough. But, if you are trying to make a lot of char cloth at once (like in a cookie tin versus a mint tin), then go with two holes.

  1. I would also like to recommend trying another source of tinder. Use lint from your clothes dryer filter. Like char cloth, use natural plant material…as cotton. But this is harder to make “in the field” than char cloth…it must be prepared ahead of time at home, and dry stored & taken with you to the field.

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