Using a 3M air sander to polish

[flyingtoaster]

I have been researching this site and how to use dual action polishers, particularly this article http://www.autogeekonline.net/forum/hot-topics-frequently-asked-questions/24936-can-air-powered-da-sander-used-polish-paint.html

Originally, I was going to buy a Porter Cable, but my dad is a 3M sales rep and we have about 20 air sanders in the garage. Here is the 3/16 orbit model sold on Autogeek 3M Random Orbital 6 Inch Air Sander 20325, electric sander, palm disc sander, dual action sander (http://www.autogeek.net/3m-orbital-air-sander.html)

We have several of those, as well as 5/16 orbit and 5/32 orbit. We also have just as many 3" sanders. The 3M pads we have in the garage are 3" and 5.5" orange, white, and black pads. There is no information online about what kind of cut these pads have, but orange feels the firmest, white has medium firmness, and black is the least firm. So I assume they are equivalent to Lake Country pads. Here are the compounds I own:

3M Finesse it II Finishing Material (bottle says it removes 2500 grit scratches)
3M Finesse it Final Finish (I can't find any information about this product)
Menzerma 85U
Meguiars 105 (on its way)

I also ordered a LC grey and red pad to compare to the 3M pads

The car is a black 07 Lexus with scratches into the clearcoat of varying depth. My plan is to start with M105 and the 3M orange pad, then Finesse it II on the 3M white pad, followed by 4 test areas for the jeweling step:
Menzerma 85U + 3m black pad
Menzerma 85U + LC grey pad
3M Final Finish + 3M black pad
3m Final Finish + LC grey pad

My question is about what speed to run the sander at. I plan on going at it with a full 90psi and full throttle. I already tried this on a washed and clayed test spot with the 85U. At firm pressure, the orbital would just vibrate and not spin. At medium pressure, it would spin between 2-5 turns per second (120-300rpm) and at light pressure, with only the foam fingers on the pad touching the paint, it would spin a little faster. Is this too slow to get results? How fast do Porter Cables appear to spin?

[Fly bye]

How fast do Porter Cables appear to spin?





Not that fast.

The PC spins the fastest with the 4'' pad. The way to tell how fast it is spinning, or if it's spinning at all, is to put a small black dot, using a sharpie onto the backing plate.

You mentioned that with firm pressure, your pad wasn't spinning very much, or not at all, but your pad IS cutting. The machine is still orbiting very rapidly.

[A4 1.8tqm]

Assuming you have an adequate air compressor to run the palm sander for extended periods of time (they are CFM hungry), you should be good to go. I do think that the lack of rotation speed will slow down correction times, on the other hand you don't have to purchase a new machine... that's a plus.

I'm looking forward to hearing about your experiences with the pneumatic palm sander(s).

[Mike Phillips]

My question is about what speed to run the sander at. I plan on going at it with a full 90psi and full throttle. I already tried this on a washed and clayed test spot with the 85U. At firm pressure, the orbital would just vibrate and not spin. At medium pressure, it would spin between 2-5 turns per second (120-300rpm) and at light pressure, with only the foam fingers on the pad touching the paint, it would spin a little faster. Is this too slow to get results?



Below surface defects are best removed when the pad is rotating because it is when the pad is rotating that it best removes small particles of paint off the surface. It's this leveling process that removes the defects and restores a flat but glossy surface.

The article your read about using a air-powered DA sand was written by me and everything I wrote in it was accurate as to the DA Sander, Pads and air pressure I was using in our facilities.

While you don't need the pad to be spinning fast like a rotary buffer would spin a pad, you do need it rotating under moderate to firm pressure for the correction step.




How fast do Porter Cables appear to spin?


Under pressure... not very fast but using the right pad and good technique it spins or rotates fast enough for hundreds of thousands of people to polish paint to perfection for decades now...

With both electric and air powered DA sanders it is vitally important that the pad is held flat against the surface, tipping the pad and putting more pressure to just one side or portion of the face of the pad will slow down and stop the pad from rotating.


:)

[flyingtoaster]

Assuming you have an adequate air compressor to run the palm sander for extended periods of time (they are CFM hungry), you should be good to go. I do think that the lack of rotation speed will slow down correction times, on the other hand you don't have to purchase a new machine... that's a plus.

I'm looking forward to hearing about your experiences with the pneumatic palm sander(s).
Thanks for the support. I should be fine because I am able to keep the pressure at 90psi for a full section pass.


Below surface defects are best removed when the pad is rotating because it is when the pad is rotating that it best removes small particles of paint off the surface. It's this leveling process that removes the defects and restores a flat but glossy surface.

The article your read about using a air-powered DA sand was written by me and everything I wrote in it was accurate as to the DA Sander, Pads and air pressure I was using in our facilities.

While you don't need the pad to be spinning fast like a rotary buffer would spin a pad, you do need it rotating under moderate to firm pressure for the correction step.




Under pressure... not very fast but using the right pad and good technique it spins or rotates fast enough for hundreds of thousands of people to polish paint to perfection for decades now...

With both electric and air powered DA sanders it is vitally important that the pad is held flat against the surface, tipping the pad and putting more pressure to just one side or portion of the face of the pad will slow down and stop the pad from rotating.


:)
So the pad just needs to be spinning, no matter how slow? I'm definitely okay with that. My setup seems to be almost identical to your writeup, except I had my test run at 90psi and you had yours at 100psi. I might bump it up if I think it will give me better results. I know you also tried Surbuff pads and they rotated more easily. I ordered some with my M105 and pads. My Auto Geek order won't arrive until Monday, so I'll start my project some time next week.
http://www.superhonda.com/photopost/showphoto.php?photo=101094&size=big&cat=&ppuser=61269

[spellrm]

I've been using an air sander to polish paint for a couple of months now. It's not better than an electric polisher, but since it's already available to you, I say go for it. I use mine in a car shop that has heavy duty compressors that can handle anything thrown at them. The only complaint I have is how much larger and bulkier an air hose is compared to the electrical cord. Also, the vibration doesn't stop at the polisher; your shoulder gets a nice (read: annoying) massage because the vibration continues to the air hose that is sitting over your shoulder.

Let us know how it works.

[flyingtoaster]

It's Monday and my LC pads and Megs 105 came in the mail. I did one of my headlights and I'm disappointed. There is noticeable swirl in direct sunlight or when my headlights are on.
http://www.superhonda.com/photopost/data/500/2010-08-02_18_53_58.jpg
http://www.superhonda.com/photopost/data/500/2010-08-02_18_54_07.jpg
The white specs are just lint from my cotton hand towels.

Here is the process I used:

3M 3 inch DA air sander:
1000 grit wet/dry sanding pad w/ foam backing
3000 grit wet/dry sanding pad w/ foam backing
(both sanding pads were wetted with a quick detail spray)
3M orange pad + M105


3M 5.5 inch DA air sander:
LC black pad + Menzerma Final Polish 85U
LC red finishing pad + Menzerna Super Finish PO 106 FA

I did 3 slow section passes each time. The first two were with firm pressure with the pads moving at about 1 rotation per second. The third pass was done with light pressure for faster rotation.

Any ideas why I'm getting swirl? I don't feel comfortable polishing my clearcoat until I perfect these lenses.

[spellrm]

It's Monday and my LC pads and Megs 105 came in the mail. I did one of my headlights and I'm disappointed. There is noticeable swirl in direct sunlight or when my headlights are on.
http://www.superhonda.com/photopost/data/500/2010-08-02_18_53_58.jpg
http://www.superhonda.com/photopost/data/500/2010-08-02_18_54_07.jpg
The white specs are just lint from my cotton hand towels.

Here is the process I used:

3M 3 inch DA air sander:
1000 grit wet/dry sanding pad w/ foam backing
3000 grit wet/dry sanding pad w/ foam backing
(both sanding pads were wetted with a quick detail spray)
3M orange pad + M105


3M 5.5 inch DA air sander:
LC black pad + Menzerma Final Polish 85U
LC red finishing pad + Menzerna Super Finish PO 106 FA

I did 3 slow section passes each time. The first two were with firm pressure with the pads moving at about 1 rotation per second. The third pass was done with light pressure for faster rotation.

Any ideas why I'm getting swirl? I don't feel comfortable polishing my clearcoat until I perfect these lenses.

Maybe after the 105, try using Meguiars PlastX. It's a mild plastic polish that has removed 2000-3000 grit sanding scratches for me in the past.

Then again, you did finish it off with a mild polish so maybe I'm way off base here.

[flyingtoaster]

Maybe after the 105, try using Meguiars PlastX. It's a mild plastic polish that has removed 2000-3000 grit sanding scratches for me in the past.

Then again, you did finish it off with a mild polish so maybe I'm way off base here.
Thanks for the reply. I don't have pictures, but I did the driver's side headlight today and the clarity is great but the level of swirl is worse than the passenger side. After using the orange pad with M105, I went with a 3M black pad with 3M plastic polish. Keep in mind, I used the same process as the 3M headlight kit, except I used a different compounding polish with the orange pad (M105 instead of 3M Polishing Compound) and I went a step further by finishing with a black pad and mild polish.

Here's what I know:

Gray colored polishes are generally milder than white colored polishes. Just look at the Menzerna chart Menzerna Polishing Compounds Products, menzerna polishes, menzerna car polish, menzerna nano polish, menzerna final polish, menzerna compound, (http://www.autogeek.net/menzerna-of-germany.html)

3M plastic polish is white in color, so I assume it is more rough than Menzerna Super Finish, which is gray. Further, I finished the driver's side headlight with a 3M black pad, which doesn't feel as soft as the red LC pad I used on the passenger side. So either the pad or the polish, or a combination of both are causing swirl. I didn't want to split hairs and buy Menzerna 85RD, but I may need it.

In other news, I was able to completely finish a test area on the black Lexus, swirl-free, with M105 + 3M orange, Menz 85U + LC black, followed by 3M final polish + LC red. This combination wil produce swirl on headlight plastic but not clear coat.