If they both finish identical, why not go with the one that has more cut? Sure, the 85rd will abrade less clear coat, but they're both very fine polishes, so it can't be THAT big of a difference. I still wonder if 106FA takes longer to break down because there's more abrasives?
I once had a bit of a discussion with Rydawg about using Menzerna polishes, especially 106FF, 106FA, and 85RD. Here's a summary about what he said:
1. Make sure the paint is *completely* clean of any residues. Even QD residues.
2. Work it loooong. Really long. Seriously... Loooooooong.
I spent a long time (pun unintended) working on point 2. Again, this is with a rotary, but anyway...
Rydawg told me that most guys don't work menz finishing polishes long enough. Menz polishes take quite a while to break down, even with a rotary. Most guys work the polish til it goes clear, then stop. While that works with most traditional diminishing abrasive polishes, you're leaving gloss on the table if you stop here with Menz finishing polishes.
Work it til it goes clear, then keep working it. Eventually, it will go *super* clear. To the point that it looks like there's baby oil on your paint. That's how far you want to go. Once the polish looks like baby oil, stop. Remove the oily residue. Do an IPA wipe. If the paint looks as glossy with the residue removed as it did with the oily residue on it, you've hit max gloss. If not, do another application, and repeat the process til you can't tell the difference between gloss levels with the polish residue on it/off it.
Sometimes you won't get enough working time out of the first application to work it this long; it might start drying out on you before you can turn it into baby oil. If that happens, just add a bit more polish. Don't remove the residue, just add a bit more and keep working it.
Eventually, you'll get enough working time to work it til it looks like baby oil. Going for max gloss with Menz polishes isn't exactly a time saver, but the results can be well worth the additional time spent.
On a nice hard clear, like say an '07 vette (
), you can really jewel it up to an unreal level with a rotary and a menz finishing polish.
The same technique can be used on soft paints, too (with a rotary), as long as you use FPII instead of one of the ceramiclear rated polishes.
