Ink “uptake” is the term we use to describe how much ink is drawn into a pen’s reservoir when you fill it. While knowing the
ink capacity of a pen is good, for a repair person, knowing it’s uptake is better. A pen with a capacity of 0.75 milliliter (mL) should draw in about that much ink. If you can measure how much ink actually gets drawn in, that is an important first step in diagnosing any number of problems (which are fodder for a future post). For many repair technicians, one of the final steps in approving a pen’s successful repair is to test the filling system.
So, what is the best way to test a pen’s ink uptake?
Many opinions, few solutions
There are many, many ways that people test ink uptake. In a pen with a clear barrel or window, you can simply look at the level and guess. Some people will fill the pen, then watch how much is expelled when it is emptied. On fellow we met counted the drops that fell off the nib!
In our experience there is only one reasonable and effective solution: a good digital scale.
Why a Scale?
There is one over-riding reason for using a scale to measure ink uptake: accuracy.
The reason we can rely on a scale so definitively is because of physics. One mL of water weighs exactly one gram. So with ink being almost entirely water (in terms of mass), one mL of ink weighs one gram. If you zero out (tare) your scale with the empty pen on it, fill it, and put it back on the scale, you can easily see how much ink your pen has taken up.
Considering that even a tenth of a gram takes up a fair bit of space in a sac or converter, we prefer a scale that reads to two decimals. Fortunately, they are pretty easy to find right now.
We bought this one off Amazon (where brand names mean nothing; go by description instead), and they presently sell for less than Cdn$35. You can find similar ones in corner stores across inner city North America, thanks to the ever-increasing demand by the cannabis business (who would have thought?)
What sort of features are good? Here are a few:
- Rechargeable, because who wants to buy batteries?;
- Reads to two decimals. Easily toggles between grams and ounces (which are far, far less accurate);
- Has little covers, which can be used upside down to prevent things from rolling around;
- The table size is medium, which means it can be used for other things.
Which other things, you may ask?
- Baking (especially salt quantities);
- Weighing out small amounts of epoxy;
- Soap & cosmetics making;
- Calculating postage cost (so old-fashioned!);
- Other things you might think of.
A good scale is one of our most-used tools, used for every repair job. While not often mentioned in connection with pen repairs, one should be on every bench.
