I wanted to revisit this topic especially after I re-read it and can sympathize with strum456's frustration. Ive gone through the same thing....spent a ton of cash trying outh different sandpaper, coumpounds, buffing pads, and buffing speeds etc. I spent big $$ on the 3M finishing film, 3M trizact 1500 (purple discs) and the 3M 3000 trizact foam backed discs.
Here is the process I used and have played with:
6 coats of UV (800 grit after 3 + 3 more) I am a first time painter so it doesnt come out perfect.
Then I use 3M finishing film 600 grit or 800 grit and I use it by hand....put it on a 6" DA pad and spread my hand out to grab the pad and then sand by hand in forward backward strokes.
After 600-800 grit like this I do the same with 3M 1000 grit film by hand on the DA pad
Then I used the 3M trizact 1500 purple Non-film disc and spray some water on the area to use the discs wet. I use my 3/32 stroke Airvantage sander with a fam backing pad with theese discs.
Then I used the 3M trizact 3000 grit foam backed discs with a spritz of water to get the 1500 grit scratches out. Ive even followed up with the Mirka Abralon 4000 pads wet.
Then Ive used a wool compounding pad (several types) and Mezerna Power gloss (tried Megs 105 also) and try buffing it out. It buffs to a shine....if you look close though like an 1-2 inch away under flourescent light you notice a "texture" (the texture is a fine crosshatch type of pattern) on the paint surface. I discover later that its actually created by the DA sanding with the 1500 trizact.....and doesnt seem to buff out too well or in my case doesnt buff out completely at all no matter what I have tried.
So I followed the power gloss with Mezerna IP (Intensive polish) with an orange foam pad (tried Megs 205 and other brands of middle step compounds)....it buffs to a higher shine.....but 1 inch away under the flourescent lights the "texture" is still there on the paint surface. I followed up with a Mezerna final polish....buffs to a nice high shine but the 1 inch away (gotta look close) "texture" is still there.
So not knowing where this "texture" came from I examined a freshly painted clear coat surface.......My first time painting but no "texture" there...just some small waves...eyes 2 inches away under indoor lighting.
So the cross hatch "texture" is from the sanding or buffing process. Thinking its the wool, I removed the wool pad from the buffing process. Still got "texture" in the final result. Removing the scratches with a foam pad, in place of the wool was very difficult.
So instead of using the finishing film 600-800 grit on a 6" DA pad by hand I sanded with these grits using the finishing film on the DA (with a foam interface) and went back to wool for compounding. Still got texture (it was worse than before) and there was more thane wave visible in the final result.
Pissed off, I said I think the "texture" is more a result of using the DA and the film discs....I think especially the Trizact 1500 discs. With that thought I went to only hand hardblock wetsanding.
Hand hard block sanding:
Started with 1000 grit wet Nikkens sandpaper with a Durablock hard rubber block
Followed with 1500 grit Mirka wet paper same durablock
Followed with 2000 grit wet Indasa red paper same durablock
Followed by 2500 grit wet Nikkens paper same durablock
Followed by 3m 3000 trizact foam disc on the DA wet.
Buffing:
Then went to wool/Mezerna power gloss
then Mezerna IP/orange foam pad
Then Mezerna polish/black foam pad
Result.....High gloss, thane wave pretty much gone (starting with 800 grit wet hard block might help), and the 1-2 inch away "texture" under indoor flourescent light...much much less. This Texture is now much more uniform and not as prevelant....from 1 inch away.
I think crashtech mentioned in another thread about a texture he saw (only up close) in some of his results. So from my experimenting, my "texture" was mainly coming from the DA sanding using the 3M finishing film and trizact 1500 discs and maybe the 3000 trizact.....but I think the 3000 trizact is easily buffed out where as the 1500 trizact not easily buffed out.
With my hand/hardblock sanding u can just see the faint straight scratches. THis is if you stick your nose on the paint surface and actually concentrate on trying to see scratches in the outlines of the flourescent lights in the paint surface.
So I thought I would share to maybe help others who are first starting out and getting a bit frustrated especially since the DA based film discs are so expensive. I was expecting perfection after spending big $$ on all those film/trizact discs. So, for me I am getting best results by sticking with a hard block, and wet-sanding by hand. Ive tried alot of different brands of wet sandpaper and love the Nikkens (which is sold by MeGuiars) wet sandpaper sheets. Seems to cut smooth and last a long time.
In all....A very frustrating......painful process but I think I am finally on the right path that will work best for me. Gonna stick with hard block hand sanding.