After several hours of painful, boring research, that red/brown "rusty" material on that peice in your e-tank is Ferric-Oxide
-Fe2O3. After tank time and the disassociation of H2O at the cathode, some black residue left is Ferrous-Oxide
(FeO --loss of Oxygen), Magnetite. A little clean-up and either prime immediately or watch it rust again. Sometimes this isn't convenient because we may have more pieces to clean first. Here's some info as how to slow down the re-rusting-just submerge your part in cold coffee or tomato juice.
The following site : iron
In summary, a cold solution of a low pH-(acidity) will prolong re- rusting from 10 to 100 hours or longer.
From my acidity scale (lower the pH to higher the acidity), from 7 = neutral
6- Urine, 5-Black Coffee, 4- Tomato juice, 3-Orange Juice, 2-lemon juice.
" Since pH is logarithmic, a change of 1 on the scale is a change of 10-fold difference in hydrogen ion concentration".
Now, the disclaimer. I haven't personally tested this YET.
You'l notice I skipped suggesting testing with pH6.
Edited by Toolpartzman, February 08, 2012 - 08:47 AM.