Found a great pen to mark HP calculator cards

[ijabbott]

(07-01-2022 01:08 AM)Xorand Wrote:  On a whim, I tried one of my Pilot Frixion pens. I had purchased a few of these pens to go along with some re-usable notebooks I picked up a year or two ago. The ink dries within a minute or so on the HP cards and doesn't smear. However, the ink wipes off clean when wetted with some water (i just used a wet finger for a test).

I've got a few cards marked with the Frixion pen and will see how they hold up long term, as well as to see if they can still be wiped clean with water after a longer period of time.

The other nice thing about these pens is they use a bistable invisible ink. Heating the ink up by friction (using the "eraser" at the end of the pen) turns it transparent. Cooling it below -10C for a while turns it visible again!