This thread may cover Spirit scales handles and Spirit/SAK blades, i am trying to polish the scales first. I've got an inexpensive 12-set of diamond polishing paste (syringes with 40micron down to 0.5micron, see ebay), and did several successful manual
mirror polishing projects with it, so i have tons of hours of manual polishing experience so to speak. Why manual? Because i don't own a dremel, never mind, it doesn't matter here.
Some youtubers buy that set for stropping knife blades edges but imho polishing paste is not very suitable for stropping. While polishing paste and stropping paste are basically the same thing and can be composed of the identical set of ingredients and grain size, it is the 'recipe', i.e. the composition of the ingredient concentrations which makes the difference (low concentration of the active abrasive ingredient vs. high concentration).
New out of the box, Spirit scales come "nicely" polished. Its "mirror polish", produced afaik by factory tumble polishing process, is a dull
mirror polish. The surface seems hardened and the finish is non-directional and would correspond to a very fine diamond grain size. Interestingly, it was super easy to eliminate the dullness
with 1.0micron diamond paste, so the "mirror polish" became as bright as a real mirror.
However, the finish of the four scales had different degrees of non-crispiness
: 3 were okay, while 1 had imho too many non-microscopic (simply called "tiny") tumble grain marks left from the tumble polishing process. Of course, it would be possible to polish them away with low-grit sandpaper or solid paste on a polishing wheel, i am sharing with you the information that it is practically impossible to do so with 40micron diamond paste, unless you consume 10 days 10 syringes and 10 dremels for the task. Also, "too much" material would need to be removed in order to remove all the tumble grain marks; similarly to deep scratches in the Spirit scales, you cannot polish them away. Let me assume that most readers do not own a dremel like me. So all i use is a Q-tip with the diamond paste.
I learned that even against tiniest non-microscopic scratches on the Spirit scales, my 40micron paste was powerless. On a perfectly smooth flat surface, 40micron produces a near-mirror-like finish already, a dull mirror finish, with visible microscopic directional lines. Btw I do own a portable 100x microscope for checking my stropping or polishing intermediary results.
Since the original Spirit finish is void of directional lines, it would compare to 3.5micron diamond paste. This has to be true since it is possible to brighten up the shine noticeably with 1.0micron diamond paste, as mentioned earlier. So FYI, if you ever try to polish your Spirit handles and use anything coarser than 3.5micron (ooh don't ask me to which grit this corresponds
), rest assured that it will ruin, not improve, the finish, and you will see the microscopic directional lines corresponding to that micron used.
Here another tip, do not use longitudinal polishing movements, i.e. in direction of the length of the scale, because that will produce tiny longitudinal excavations originating from the tumble grain marks. That's an interesting general observation and i learned it the hard way. Circular polishing movement is the only way to go. I don't know why this does not produce those tiny excavations. RL is full of mystery lol.
Please share how your polishing attempts with Spirit scales (or SAK blades) went, how you were successful. Got some pics? I have come to accept that 1 scale has more tumble grain marks than the others, so i will just continue with the diamond paste, 28micron, 20, 14, …, 1.5, 1.0, 0.5. I would share photos then! I am not saying that polishing SAK blades or Spirit scales to 100%-mirror polish —like a real real mirror!— is art or impossible, but i am
saying that it is darn challenging to get near there: for one thing, a real mirror does not
have tumble grain marks in/on the finish!! And I am saying that mirror-polishing a Leatherman Surge is much easier because it does not
have tumble-polished scales. It is not challenging to mirror-polish a Surge (blade or scale). I have a Surge.