The nib on the Parker 21 isn't steel. Parker branded it as Octanium. It's a high-performance metal alloy that was originally developed for the purpose of making watch springs. Iron is always the main component, or base metal in steel. Instead, this alloy is mostly cobalt. The composition is 40% Cobalt, 20% Chromium, 15% Nickel, ~15 Iron, 7% Molybdenum, 2% Manganese, 0.15% Carbon, 0.04% Beryllium. The alloy is highly corrosion resistant, has a long fatigue life, is resistant to stress corrosion cracking, and has good ductility (resistance to deformation). It's currently specified by ASTM F 1058 and ISO 5832-7, and is commonly produced as FWM 1058, Conichrome, Phynox and Elgiloy. The tipping material was branded by Parker as Plathenium, but is really Ruthenium, Element 44 on the periodic table. It's a Platinum group metal (closely related to Iridium and Osmium) and is extremely rare, although it can be produced as a byproduct of nuclear fission. One source states that the Parker 51 gold nibs from 1944 onward were RU Nib, consisting of 96.2% Ruthenium and 3.8% Iridium, so it's likely the same mixture on the Parker 21. Interestingly it's not harmed by acids, but is attacked by bleach at room temperature.
The biggest problem for me with Platinum Carbon black is it doesnt belong in a demonstrator unless you are gonna deep clean it after you put black in the pen its gonna stay black till you take it apart get all the carbon particles out and put it back together but you dont have that problem with waterman black of pretty much any other black that I know of most just wash out easy peasy but platinum carbon black takes a special kind of cleaning to get it all the way out
do you have a platinum preppy if now Ill buy you one to put the carbon black in ink and you can draw with it it is very stiff but it drys with the pen almost instantly like 1 to 2 minutes and if you're outside in sun it may take less so but I've known people who do plainair who take their preppy do a sketch and 3 minutes later they are painting on it so :)
Hey, I hear you are looking for a vintage flex-nibbed pen. We can chat face to face if you like. Here on RU-vid or via other system. Email me at piergustafsonstudio@gmail.com
