The Bic Cristal Pen is the object I use most frequently for drawing.
14.9 cm long with the cap, and 14.4 cm long without the cap
We are made for the most part of water, a Bic pen, from four elements:
Polystyrene, Polypropylene, Tungsten Carbide and Alpaca.
Let’s begin to describe the cap. In polypropylene, it is the same color as the ink into the tank, and has the particularity of protecting the pen, in the tip and in the sphere.
It has a hole, which prevents people from being suffocated if they swallow it.
The sphere is a very important part, it is made of a metal, hard and resistant, and without imperfections, it is made of tungsten carbide.
The tip, which is of nickel silver, fixes the sphere in the writing movement and is located between the sphere and the beak, which is that orange part that we see at the end of the transparent tank, in fact, the beak, acts as a junction between the tip and the ink tank, and is made of polypropylene.
The reservoir is a transparent tube, which holds 0.4 grams of ink, and is also made of polypropylene.
The barrel is hexagonal in shape, for a simple reason, because it allows the hand a safe and comfortable grip, as well as the ease, being hexagonal, of being able to place many more pens in a small space. A part absolutely important is the hole placed on the shaft in the middle part. It serves to regulate internal pressure. Without it, without this hole, the slightest change in pressure, between the outside and the inside, would result in the ink leaking or in any case a malfunction in writing. And finally, we have the closure, which protects against spills, and keeps the ink in the pen in the right pressure. And it’s the same color as the ink inside the tank. The ink is the fundamental and most innovative part of the whole object.
Although Bic and other ballpoint pen manufacturers keep their ink composition formulas secret, they all have fairly common ingredients. The pigments are mixed with oils, such as benzyl alcohol or phenoxyethanol. Fatty acids are added to lubricate the ballpoint pen and resist blockages. Surfactants help the paper absorb the ink before it dries. New formulas are constantly being developed to improve the performance of the Bic pen, and the ink we use now, of course, is not what they used in 1950, or 1970, and certainly what we use today will not be the same as will use in the future. New discoveries and new formulas will always make Bic a better product, because the secret of the whole pen, of the Bic pen, is right here, in the ink.
These improvements of the ink, for example, have led to the development of particular pens, unthinkable until a long time ago, such as the Bic Large, which has a diameter of 1.6 mm. The ink in this case is particularly fluid but manages not to escape impetuously, so the sphere can adjust it perfectly. There will be other developments in the future, but the developments of the pens, however, will always go hand in hand with the development of the ink. You will have noticed that the tank is not filled to the brim with ink, this is because it expands if it is heated, therefore, with the heat of our hand it could come out of the pen, and how many times it has come out of the pen, for this reason, motif, alas, in the pocket, or inside a jacket. Another curiosity. If you have the time and the desire and you have a sheet of paper three and a half kilometers long, take the Bic pen and start drawing a line, all along this sheet. Eventually, when you get to three and a half kilometers, the pen’s ink will be completely gone. Finally, how much does a Bic pen weigh? A Bic pen can weigh up to 6 grams. Around the world, nearly 100 billions have been sold since 1950, and if you want to start a letter or a story, a Bic pen can write nearly 45,000 words.
You just have to take a Bic Cristal pen and closely observe what has been said above and never stop having it with you, for me, it is now an inseparable companion.

The Closure