How Is Graphite Lead Made for Pencils?

Have you ever wanted to know how pencils come into existence? Or how many words can you write with one pencil?

Well, a pencil is a long narrow tool used for writing and drawing. It consists of a solid pigment core that adheres to the sheet or surface, thereby making marks. The core of the pencil comprises a blend of graphite powder and a clay binder.

What do 35 miles and 45,000 words have in common?  Only the output of your average pencil!!  That’s write(srry bad pun)!  It’s amazin’ what compressed earth and pulped wood can do!

Pencil making is a complex process. But, in a nutshell, one can say that the graphite rods are inserted in wooden slats on the top of the glue. That is how we get pencils.

Now let us see how graphite takes its shape and properties for a pencil?

Processing Of Graphite For Pencil

Graphite pencils’ other name is lead pencils. These pencils produce grey or black marks by physical abrasion. The process of making graphite for the pencils isn’t as easy as it looks. Let’s have a brief look at the procedure:

• The first step involves grinding the graphite and clay in a huge metal drum, which contains rocks.
• Then upon pulverization, a fine powder of graphite and clay becomes when the drum is rotated.
• Water is added in regulated quantities, and the mixture is left to blend for at least 72 hours.
• After three days, the drum is opened to check for a consistent mixture. If an even mixture is obtained, then the remaining water is rinsed off. But, the remaining grey sludgy and muddy mixture is left behind until it hardens.
• The hardened gray sludge is ground up again. Some more water is added for obtaining a smooth, malleable paste.
• If the color of the mixture appears to have a light color, additional carbon is added to make it darker.
• The graphite rods are made by forcing the soft paste into a long metal tube with a small opening. These rods are then cut into desirable length so that they fit into wooden pencil slats.
• These pencil leads are heated at a very high 1800 degrees F temperature to make them smooth and hard.
• For obtaining a smoother lead, the leads are dipped into oil or wax. These leads can then be inserted into wooden or mechanical pencils.

What Properties Of Graphite Makes It Perfect For Pencils?

Graphite comes from the Greek word “graphein,” which means to write. It gets its profound utility from its various characteristic properties. Have a look at some of these properties:

• Basic Structure: It is one of the most stable allotropes of carbon. It also has a crystalline structure. It occurs as flakes and veins deep beneath the rock fractures or in the form of amorphous lumps. Yet, graphite is available in the form of a flat sheet. It consists of strong covalent carbon bonds in the shape of hexagonal cells. All these sheets lay above one other retain a voluminous structure.
• Softest Mineral: Graphite is one of the softest minerals. It exhibits a lustrous and slippery feel due to its layer like structure. This softness is the reason it is very useful in making pencil cores. It is gray or black and produces marks of similar shade upon physical abrasion.
• Insoluble In Water: Graphite remains insoluble in water and other organic solvents. Water-resistance is another plus point for graphite being used in pencil cores. This is because the attraction between water and carbon molecules is not strong. One can break it down and overcome it by covalently bonded carbon atoms in graphite.
• High Melting Point: Graphite gets its hardness from its high melting point of 3650C. Thus, it becomes ideal for pencil cores.

Uses Of Graphite

Graphite is useful in different facets due to its physical and chemical properties. Have a look at some of these uses of graphite:

• Lead Pencils: As discussed above, the solid core of the pencils consists of a blend of graphite and clay. While the graphite produces visible marks on the paper, clay acts as a good binder. It thus adheres to the paper’s surface. Pencils with higher graphite content are darker and softer.
• Lubricants: A lubricant is anything that reduces friction. When graphite reacts with moisture, it gets a thin layer deposited over its surface, which reduces friction. It can work as a lubricant up to a high temperature of 1450 degrees Fahrenheit.
• Refractories: Graphite serves as refractory material as it can withstand high temperatures. It is useful as a component in manufacturing materials, including steel and iron.
• Lithium-Ion Batteries: Lithium-ion batteries use graphite on their positive terminal as the anode. Graphite exhibits great electrical conductivity.
• Other uses: Graphite has multiple other uses. Its properties: electrical conductivity, chemical resistance, and bonded structure can be very useful. You can use it for medical implants and substitutes for plane parts.

Frequently Asked Questions

Where does graphite for pencils come from?

Graphite comes from its mines in the form of flakes and lumps. It is then grounded with clay to produce a malleable mixture for making graphite rods. These rods are then squished into tubes and cut into proper lengths for making pencils.

Why is graphite suitable for pencils?

A pencil produces long-lasting gray or black marks on paper. Graphite being a greyish-black substance combined with clay, acts as a binder. It then becomes perfect for pencils. This combination adheres to the surface and produces dark marks.

How much graphite is in pencil?

The higher the content of graphite, the darker and softer the pencil is. Thus, a soft pencil comprises about 90% of graphite, while a harder one comprises about 20% of graphite.

How do you harden graphite?

The mixture of graphite and clay with water is left for about three days to completely dry and hard. This mixture then takes the form of a soft paste. This paste is then heated to very high temperatures to get a smooth and hard tip for the pencil.

Is pencil graphite poisonous?

The pencil graphite is non-toxic. This is also one of the reasons why one uses it in pencils. Even if a child swallows a broken piece, he/she might choke for some time, but there will be no severe consequences.

Are graphite and charcoal the same thing?

The two options you have for drawing are charcoal and graphite pencils. Graphite pencils have a wide range of grades. They are useful for sophisticated drawings. They are suitable for drawings that need finer details.

Charcoal but is perfect for sketching and hitting those dark values. Yet, it is generally much darker and rougher than graphite and more prone to smudging.

Check out our very own MstrSktch Pencil Drawing Set

Conclusion

To sum up, there is nothing known as the lead in lead pencils. Rather it is a soft mineral called graphite. This graphite combines with fine clay to produce dark marks that adhere to the surface of the sheet.

However, making graphite for pencils is quite tedious. There are many steps involved in its making. And all the steps involved are important. From graphite to cutting rods, everything needs to be perfect to get the best quality pencil.