Hello everyone!
I am a new PC user with a PC issue. I was using it on a sapphire metallic black 745li when i began to have issues. The trunk lid and read left door went fine. After that problems arose. The PC began straining a LOT. If I was polishing a horizontal surface, the machine would overheat and shut off. I had to lift up to keep less pressure on the paint. It was also hopping a lot. It I didn't hold it up, an edge would catch and off it would go. So....I thought washing it would help. I washed it and let it air dry. While the yellow pad was drying, I decided to use the black pad and finishing glaze on the parts I had already gone over with the yellow. Still, the same problem, but WORSE. It was impossible to control. Also, it didn't even remove the glaze. It just caked onto the paint and would NOT come off. I had to scratch it off with my nail. One HOUR later, I'm back to the yellow pad. Again, still hopping and resisting. Creating TONS of friction. Please help! I'm using a vector polisher at 1k RPM with Yellow and 3M rubbing compound, and black with 3M finishing glaze.

PS. I began to worry when my yellow pad began to get dark grey/black. I thought I went through the clear, but I didn't leave the machine on one spot for all that long at all. I kept it moving and the paint never got even close to "too hot to touch." But then again, it was like rubbing your finger on a balloon: very hard to move.

 

Is it one of these two?

http://cleanacar.com/vector.html?gcl...FQRuZQodqGo99A

Sounds scary, the only reason you'd have color on your pad is if you are into the paint from my experience. 3M Rubbing compound is super abrasive if I recall correctly. If you are using it and pressing down with a rotary, it's going to cut very quickly.

 

First off, like all detailing issues, we need to start off on the right foot with the proper diagnosis. Most importantly here is to realize the title is wrong. You are using a rotary buffer but asking for PC Help. Based on what you've posted over on my site



The question I have for you is---do you realize that your rotary is NOT a PC and therefore the polishing techniques, speed, pressure, chemical choice, pad choice, etc.. that we discuss here won't apply??

The hopping is common on the rotary buffer when you don't have enough chemical on the pad, but even with a saturated pad, you can still have pad hop. Another problem is that you're using chemicals and pads that are unfamiliar to nearly everyone here on NAM, so you're not going to find much help.

The fact you're using a cheap rotary could also be a part of the problem. I had the Harbor Freight, aka Vector, polisher before I got my Makita and it was a total waste of $60. There is no comparison between the power and control over the two.

If you're seeing color on your pad, there are a few possibilities.

1.) You're working on a paint with a tinted clearcoat (common on Lexus but not BMW's)

2.) You're working on a car that's been repainted partially with single stage paint that doesn't have a clear coat on those parts (this is a new car I believe so I doubt this)

3.) You have gotten the polisher close or over some rubber seals and picked up contamination on the pad.

4.) You polished over an area that had been touched up and you're picking up that paint.

5.) Worst case scenario, you've managed to polish through the clear and into the base. (not likely though possible)

So to address your concerns, you really either need to find an expert--maybe call my friend and forum member Perfection who has offered free help to you--who is familiar with that system--or stop playing with the rotary and get some training on using this professional tool!!!

Richard

 

Good reply Richard, you had a lot more optimistic ideas about where the pad color could be coming from.

 

I have no assistance, I just wanted to say this thread freaks me out. I really really hope the OP was not using a rotary like a PC.

 

What concerns me most about this whole scenario is that we've got a pretty expensive BMW, yet the OP wants to use the products that he's been given--not what he wants to use---forget the fact that whoever gave them may not have even realized he was a rotary newbie, nor what he was trying to correct. You should NEVER be learning to use a rotary on a precious car--a junker yes, a new car worth money?? Never.

Granted several of my most respected forum members have given him the official ok on the choice of products and pads--it's not something I would be using though.

I've found great success with using Prima Swirl with a flat white pad or a moistened orange pad on the rotary at slow speed--around or less than 1000rpm, with very slow arm movement--constantly checking to make sure the paint isn't heating up, but working it in long enough to fully break down the diminishing abrasives. The result is much faster and cleaner than the PC and because of the slow speed is still safe--but I couldn't say that using the chemical/pad combination shown here.

Richard

 

I have already visited with the local bmw/ferrari detailer. I have bothered him enough and wanted to get a second opinion anyway. I will try using more product now. I happen to be a very cheap person and probably haven't been using enough.

Another thing, I know the tools I'm using are quite abrasive. But, I'm only getting about 70% of the scratches out. The other 30% which are from drying are still there. Do I just need to go over it longer?

Thanks....
William

 

The variables are too many to say. I can give you suggestions based on my own experience but they may not apply since I hate those pads you're using, and I wouldn't be using the abrasives you're using. If you think you're cheap, then you should set your expectations within the same mindset.

A bottle of Swirl and an Orange and White pad will set you back, what $50?
Considering the cost of repainting your car--thousands of dollars, and it being metallic which means it may not look perfect--you're skimping in the wrong places IMO.

In regards to technique--have you done a test spot yet?? Have you made one spot perfect using the tool and chemicals you've chosen? Have you tried replicating this on one of the problem panels??

I can polish out just about any BMW or MINI using an orange pad and a white pad on my rotary and Prima Swirl. The result will be flawless. I could also use the Meguiar's system--a bottle of M80 and their yellow W8006 flat pad and finish with their tan W9006 finishing pad and M80 or M82. Both systems have very different strategies and approaches though, and there could be additional variables in chemical/pad choices.

Get a hold of the Meguiar's rotary polishing video. It's on VHS, but there are places around the net that have converted it to streaming video. Maybe take look at meguiars.com for assistance.

I produced a rotary polishing DVD as well, but it's not for sale due to copyright issues.

My point is, you can't learn to use the rotary buffer from reading comments on line. You'll do it by learning and making mistakes. The scratches you've pointed out can likely be rectified with the right tool such as the PC using an orange pad and Swirl.

If you really want to tread down this path, then go on over to Autopia.org and tell people you are a rotary newbie and want to get some advice on using the compounds you've chosen on the 745. Be very specific with your problem and how you are trying to solve it for the best feedback. There are plenty of enthusiast detailers that can probably provide help more specific to your case.

re: finer scratches
Have you ever worked with wood before? For the deepest scratches, you sand using a coarse grit paper--essentially roughening up the surface with this grit. You then work that with a finer grit, to make it smoother. The towel scratches are very fine, you don't want to use a compound to remove them-unless the towel scratches were inflicted by a foreign object on the towel which caused deeper gouges.

You have given me no information to go by to provide a possible solution. How long are you working each panel? How big of a panel are you working on? What does the panel look like as you're working? Does it start off creamy and hazing looking and become more clear the longer you work on it? Is the panel dry by the time you stop buffing? How do YOU know when to stop? What do YOU do to determine you've polished enough? I have my own answers, but give us more info so we can get a better understanding of your problem. I.E. give us the symptoms and overview of what you are doing, and maybe we can provide an accurate diagnosis.

re: Thanks for changing the thread topic
However the concern is still there--do you know the difference between a rotary buffer and a dual action orbital polisher like the PC??? I'm not talking just physical differences, but how the machines differ in use during polishing and when you would use one over the other?

Good luck.

Richard

 

+1 on "The variables are too many to say."


you really can't mess up on a random orbital... unless you place your
pad face down on the ground and then start polishing with it or something
real stupid.

 

I'm still really freaked out by this thread.

 

Me too. I'm terrified of using a rotary and would never learn on a nice car. At least my dad has a nicely neglected van that I can practice on when I do get one...

 

you guys sound like me while i practiced PDR on my previous civic.

hitting the panel with a golf ball and then pushing the dent out. car
had at least 60-70 dings but all were pushed out. had excellent trade-in
value too. no one could tell it was dinged..well, noone but another PDR
tech.

i also recommend you go to a body shop and ask them for a free trunk or
door that they're going to toss out from an accident car. you can
always practice on that, also master your wet sanding techniques, PDR,
etc.

 

While working a pannel, a little bigger than a 1'x1', heres what happens. my first pass, there is sometimes a little product residue left from the pass. But, after working the area a second time, theres nothing left but a very thin layer of film. You can't really tell unless you wipe it. Does that mean I'm using too much or too little product?

I do not know the difference between a PC and a rotary.

 

Well that would explain a lot of the problem...

A PC is a random orbital. It osscillates while it spins, which keeps it from burning the paint. You can pretty much lay on a PC and not burn paint. Most everyone here uses a PC because it's safe.

A rotary just spins. It is much more difficult to use and very easy to damage paint with. It gets much hotter and will spin til it burns right through the paint. People who use rotaries have had a TON of practice at it before they even touch paint on a car that has value.

That's my layman's version. I'm sure OG has a better technical explanation of the differences

 

I knew that difference, but thought there was more to it than that. Jut fyi, the paint never gets hot. If a spot gets any warmer than the rest of the body, I stop immediately and let it cool. No part ever gets more than 10˚ warmer than the rest. I move the machine constantly. Never stopping.

 

The rotary by it's inherent nature is more aggressive than the PC. It works faster, and causes more damage faster too. It offers more correction capability than what the PC can in the right hands.

The rotary is often used for major correction before following with the PC as a finishing tool.

The pads and chemicals are interchangeable but the aggressiveness factor on the rotary is usually one or two levels higher. So if I needed an orange pad on the PC and Swirl, I might use a white pad and Swirl or white pad and Finish with the rotary to accomplish a similar amount of work.

Heat isn't your only enemy when polishing. Heat is a by product of polishing that leads to burns, however you can polish through the clear without heating up the paint first. Just like if I take 60grit paper, I can sand through the clear with a few strokes--without needing any heat---I could probably do 5 or 10 times as many strokes with 3000 grit. For polishing out swirls and scratches on soft BMW paint, you don't need a compound.

Compounds are the most aggressive forms of polish. They are normally used for heavy paint removal for things like removing wet sanding marks or deep gouges and scratches where paint removal is desirable. Most of the time we don't polish with compounds because they are too aggressive. They also tend to haze the finish, so you need to use finer grades of polish with the appropriate pad to get the job done right.

 

do we know the difference between a manual tooth brush and an electric one?


jk

 

No ken, can you please elaborate?

Haha....jk

 

OG, thanks for all the advice. I now realize how powerful the rotary is and how much damage it can do. I think I'll take all you info you've given me and pay another visit to the local polishing guy for some more help. Thanks.

 

Because I don't know this polishing guy, and just because he does Ferrari's and BMW's, that alone doesn't give me confidence that he's necessarily an "expert".

Look at what he uses. Is he using wool pads?
Is he using glazes or is he polishing? If he's polishing, what system is he using??
What does he wax with--synthetic or carnauba? How does he apply it? With a two handed orbital or a PC or the rotary?

How is he removing it--with towels, or bonnets? What do his towels look like?
What kind of working condition is he in? Dark garage? Flourescent lights? Have you seen his work in the sunlight?

Buy a Brinkman Dual Xenon flashlight from PepBoys for $24. Learn how to use it, then visit this guy. Shoot some areas of the paint and see if it's swirl free. If he questions what you are doing, and looks scared, then he isn't a pro that you want advice from.

If he is familiar with the light and encourages you to inspect the work, that's great, but expect that doing this may get you thrown out of his shop forever.

Richard

 

This guy is definitely a pro. He uses a rotary with lake pads. He spends about 10 hours for a full polish and wax. Synthetic for winter and carnauba for the weekend cruiser. He uses MF towels for wiping off excess product that are ~$10 a piece he says. They have never touched the ground. No wool pads, instead, he wetsands. He is highly respectable. When I went over on a sunny day at high noon, he was just finishing up a friend's camery. It looked better than the day it rolled off the lot. (No surprise there...) His garage has more lights than a football stadium - one for every angle. I'm positive he knows what he's doing -- for sure.

 

Check this out;
http://en.wikipedia.org/wiki/Random_orbital_sander

And this;
http://acronyms.thefreedictionary.com/Dual+Action+(sander)

And this;
http://en.wikipedia.org/wiki/Disc_sander

Porter Cable(PC) is probably the most popular of the Dual-Action, of the polisher/sanders, some call it a Random Orbital(RO).

Hope this helps

Mark