The simplest form of carbon cloth, commonly known as char cloth, is created by subjecting natural fibrous materials to a controlled heating process in an environment with very limited oxygen. This process, known as pyrolysis or thermal decomposition, transforms the organic material into almost pure carbon.
Understanding the Carbonization Process
Making carbon cloth, especially char cloth for practical uses like fire starting, is an accessible and straightforward process. It involves carefully burning organic materials in a way that removes volatile compounds while preserving the carbon structure of the original fabric.
Step-by-Step Guide to Making Char Cloth
Creating char cloth requires just a few basic materials and careful handling. The goal is to heat natural fibers until they become carbonized without turning to ash.
1. Gather Your Materials
The quality of your carbon cloth starts with the selection of the base material.
- Natural Fabrics: Choose materials made from natural fibers, as synthetic fibers will melt rather than carbonize effectively. Excellent choices include:
- Cotton: Old cotton t-shirts, denim, or cotton rags are ideal due to their abundance and good charring properties.
- Linen: Known for its strength, linen also produces excellent char cloth.
- Jute: While coarser, jute fibers can also be carbonized, offering a different texture and burn rate.
- Avoid any fabrics treated with fire retardants or synthetic blends.
- Airtight Container: You'll need a metal container that can be almost airtight but has a small vent.
- Altoids Tin or Similar: A common and effective choice is an empty Altoids tin. Puncture a small hole (about 1/16 to 1/8 inch in diameter) in the lid using a nail and hammer. This hole allows gases to escape, preventing pressure buildup, while restricting oxygen entry.
- Heat Source: A consistent and controllable heat source is essential.
- Campfire or Fire Pit: A traditional method, where the tin is placed directly in the embers.
- Propane Torch: Offers good control over localized heat.
- Stove Burner: A gas or electric stove can also be used, though careful monitoring is crucial.
2. Prepare the Fabric
Cut your chosen natural fabric into small squares or strips that will fit comfortably inside your metal container without being overly packed. A size of about 1x1 inch or 2x2 inches is practical for fire starting.
3. Load and Heat the Container
- Place Fabric: Carefully place the cut fabric pieces inside the metal tin. Ensure the lid is securely closed.
- Apply Heat: Place the tin on or in your heat source. If using a campfire, bury it in hot embers. If using a torch or stove, heat the bottom and sides of the tin evenly.
- Observe the Process: As the tin heats, you will observe smoke or, occasionally, a small flame emerging from the tiny hole in the lid. This indicates that volatile gases are being released from the fabric as it undergoes pyrolysis.
- Initially, the smoke may be thick and white, then turn darker and thinner.
- The flame, if present, is the combustion of these gases.
- Monitor Until Complete: Continue heating until the smoke or flame from the hole subsides or stops completely. This signifies that most of the organic compounds have been driven off, and what remains is primarily carbon. The duration varies depending on the heat intensity and fabric type, typically ranging from 5 to 20 minutes.
4. Cool and Retrieve
- Cool Down: Once the smoking stops, remove the tin from the heat source. Do not open the tin immediately. Allow it to cool completely to room temperature. Opening it while hot can expose the still-hot carbon to oxygen, causing it to spontaneously combust and turn to ash.
- Inspect: Once cooled, open the tin. You should find lightweight, brittle, black pieces of char cloth that retain the general shape of your original fabric. It should be entirely black and feel somewhat delicate. If there are brown or uncharred spots, it means the process was incomplete, and you can re-heat the tin.
Characteristics and Uses of Carbon Cloth (Char Cloth)
Char cloth is highly prized for its unique properties that make it an excellent fire-starting material.
- Ease of Ignition: It has a very low ignition temperature and can easily catch a spark from a flint and steel, magnifying it into an ember.
- Slow Burn: Once ignited, it glows and smolders slowly without bursting into flame, allowing time to transfer the ember to tinder.
- Lightweight and Compact: It's extremely light, making it easy to carry in survival kits.
Common Applications
- Fire Starting: Its primary use is as tinder in traditional fire-starting methods, especially with flint and steel.
- Survival Kits: An essential component of any outdoor survival or bushcraft kit due to its reliability.
Safety Considerations
- Ventilation: Always perform the charring process in a well-ventilated area, preferably outdoors, as the smoke can be irritating.
- Heat Protection: Use gloves or tongs when handling the hot tin.
- Fire Safety: Keep a bucket of water or a fire extinguisher nearby, especially when working with open flames.
- Patience: Allow the tin to cool completely before opening to prevent accidental ignition.
Beyond Char Cloth: Industrial Carbon Cloth
While char cloth is a simple, DIY form of carbon cloth, it's important to note that industrial-grade carbon cloth (often referred to as carbon fiber fabric) used in high-tech applications like aerospace, automotive, and protective gear involves more sophisticated manufacturing processes. These involve specialized precursor materials (like polyacrylonitrile or rayon) and precise high-temperature furnaces to create fabrics with extreme strength, low weight, and high temperature resistance. However, the fundamental principle of carbonization through thermal decomposition in a controlled atmosphere remains at its core.
| Material Type | Advantages for Char Cloth | Considerations |
|---|---|---|
| Cotton | Readily available, ignites easily, fine texture | Can be brittle, may char quickly |
| Linen | Durable, good charring properties, consistent | Less common than cotton, may take slightly longer |
| Jute | Coarser texture, good for catching larger sparks | Requires thorough heating, can be more fibrous |
