Sanding and PolishingThis is a featured page

Information cut and pasted from Admactanium's post
materials


this is just what i use. all this stuff adds up so it's not exactly in-keeping with the cheapness of the paint job. but here it is:

porter cable 7424
makita bo6040
lake country polishing pads: yellow cutting, orange power pad, white polishing.
menzerna polishes: intensive polish, final polish II.
3m wetsanding paper. grits: 800, 1000, 1500, 2000 (although i hear that meguiars unigrit papers are better).

sanding

• prep your wetsand papers by soaking them in a bucket of water with some dish soap in it for lubrication. an hour or so. you want to soften up the backing paper so you don't get any stiff corners that can lead to deeper scratches.

• start with a fairly high (low number) grit wetsanding paper. 1000 or 800 if you have a lot of orangepeel and imperfections.

• use a sanding block of some sort on the flats. you can use some flexible backer for sanding any curvy spots. like a brillo pad or something of that nature. be VERY careful around edges because the paint naturally is thinner in that area so you can easily sand through.

• get a cheap plastic squeegee from the hardware store. you can use this to clear off the water in sections to check your progress. what you'll start to see is a matte surface with shiny spots. what you're doing is levelling the high spots (peaks) down to the level of the valleys.

• when the shiny spots start to get smaller and are nearly gone. move to lower grit papers (higher numbers). 1200 or 1500. the goal when progressing through the papers is to completely eliminate the sanding marks from the previous grit. you'll learn to see that happen.

- you can sand in a perpendicular direction and it'll help you see when you're finishing up on one level.

• by now the shiny spots should be disappearing and you should be left with only a matte surface. you can’t really finish it up properly until you’ve completely leveled the peaks to the same level as the valleys.

• i usually go to about 2000 grit since it makes polishing that much easier. you can go up to 3000 grit i think but i haven’t usually done that.

on to the polishing

• there are a few different types of machines you can use. or you can go by hand if you don’t mind doing a lot of hard work on it. polishers usually have foam pads that attach to a backing plate by velcro. there are other attachment methods but velcro is the most common.

the three common types of polishing machines are these:

- random orbital: the most commonly used one of these is the porter cable 7424. basically these machines just jiggle the pad very quickly in a random fashion. the benefit of these is that they are very safe when it comes to burning through the paint. they don’t generate much heat. the downside is that it takes longer to polish out imperfections and there are limits to what it can do.

- a dual action forced rotation: these aren’t very common. i have one model from makita, the bo6040. the other popular model of this is the festool rotex. these machines have dual mode. one that works the same way as the PC. in another mode, they work both like a PC and a Rotary. it forces the pad to rotate while also jiggling. this is a nice machine. i like mine. they can be used in ultimate safety mode like a random orbital but it also cuts more strongly with the rotary action.

- rotary: this is the fastest cutting machine but also the most dangerous. they’re also a bit more difficult to control. these machines only spin the pads. as you can imagine, the outer edges of the pads can get moving pretty quickly and they have a lot of cut and power. however, it’s much easier to cut through with one of these and they also tend to leave buffer trails in most users hands. you see this commonly on cars detailed by bad detailers. they look like holograms. circular swirling holograms.

the pads:

• there are a lot of different brands of pads to use with these machines. for the most part the same pads can be used on all the different types of polishers. the pads will be color coded based on their cut or aggressiveness. it’s hard to say definitively which pads do what because different manufacturers use different color codes. most often though yellow will be a “cutting” pad and white will be a “polishing” pad. cutting being more aggressive than polishing.

the polishes:

again, there are plenty of different brands of polishes. i personally use menzerna polishes. and again, there are different levels of aggressiveness in each product line. menzerna has 3 main products (in order of INCREASING aggressiveness):
final polish II, intensive polish, and power gloss.

there’s another line called poorboys that gets good reviews and of course there’s meguiars stuff that’s available at most locations. all of them are good. it usually just comes down to personal preference.

all of these modern polishes (not the tin can stuff you get at the auto parts store) use diminishing abrasives. what that means is that the grit of the polishes break down over time the longer they’re worked. the benefit of this is that it basically does the “step down” grit process we were doing with the sandpapers on its own. that’s why it’s important to make sure you’re breaking down the polishes well and letting them fully work otherwise you’ll have a hazy surface.

the process:

i only have the first two. so i’ll start with the yellow pad on my dual action and use some intensive polish. you should spritz the pad with some water to moisten it to begin.

• i use the yellow pad and apply some intensive polish directly to the pad in an x pattern. then, with the machine off, i dab the pad against the surface to spread the polish around evenly. i’ll even smear the area with the machine off.

• then i start the machine on a low speed. use that slow speed to distribute the product over a small area: maybe 2’ x 2’. when the machine is slow really take your time moving it around and apply a bit of pressure.

• you’ll start to notice the polish working in and the surface should be changing a bit already. keep going while increasing the machine’s speed. that will help the polish break down further. with the menzerna polishes you keep going until they’re nearly completely transparent.

• then change the pads on the machine and use a lower grit polish. so in my case it would be a white pad with menzerna final polish II. go through the same process with the white pad and lower grit polish. until it’s nearly all hazed out and gone.

• i’d personally finish with the pc or the random orbit mode and the lighter polish just to make sure i’ve taken out all the previous polishing marks.

you have to check your progress on this as you go. if you’re still seeing sanding marks, it’s not likely that you’ll get them out with polishing. you need to get those out in sanding. that’s why it’s important to constantly check in the sanding process to see that you’ve removed the previous level’s sanding marks.

that's basically it. from there i use a cleaner wax and then a sealant to finish it up. but i wouldn't use a sealant on a newly painted surface for at least a couple months. it has to have time to completely dry and outgas.

i'd say the most important step in the whole process from these types of paintjobs is the sanding process. you need to get all the orange peel and waves/brushmarks out of the paint before you polish. and you REALLY need to step down in grit on the papers. most polishes will not polish out much more than 1500 grit sanding marks. if you don't step down you can get a shiny surface but you'll have shiny looking sanding marks. most of the polishing attempts i've seen on this thread so far fail from not enough time and care taken in wetsanding and getting a perfectly flat surface with a low enough grit.

Aussie Driver:
My process was to wetsand with 1200 and then with 1500 to remove the orange peel and to get the paint nice and flat as well as smooth as possible.

I used the Poorboys SSR2.5 for the cutting along with a Wolfgang 6.5" yellow cutting pad. I then experimented with the SSR2.5 on a Wolfgang 6.5" orange light cutting pad for a second pass and this gave the paint a more glass like finish.

I use a random orbital polisher which has similar specs to a Porter Cable 7424. I spread the polish onto the panel with the polisher turned off, then I turned it on to the lowest speed setting to even the polish out for a minute or so, then I cranked up the speed on the polisher to max and worked in the polish until almost all of the residue had disappeared.

When I did this I only had the single cutting pad and this really slowed up the polishing as the pad became so clogged that I had to wash it and then rinse it after completing each section of the hood. I was working on fairly small areas of the hood, basically I polished about a quarter of the hood each time, then I'd wash/rinse the cutting pad and then do the next area.

I have ordered a second cutting pad and some Poorboys SSR3 which is described as a "heavy duty compound" compared to the SSR2.5 which is a "medium abrasive". Theoretically the SSR3 should produce a slightly flatter finish and do it faster than the SSR2.5. It should arrive in the next day or so, and once I have had a chance to play with it I'll post up some more pics of those results.

I'm still experimenting on my exact polishing sequence, but at the moment I'm leaning towards using either the SSR3 or SSR2.5 with a Wolfgang yellow cutting pad, then the SSR2.5 with a Wolfgang orange light cutting pad, followed by a couple of passes of SSR1 with a Wolfgang white polishing pad to improve the clarity of the reflection.



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