Rotary Buffing Techniques - How Variables Impact Results

[Michael Stoops]

How you use a rotary buffer, your technique, can impact your results during defect removal. Sounds obvious, right? So which technique is right? Therein lies the rub - various techniques are used around the world to achieve essentially the same result, but those techniques vary for different reasons, and the goal of this article is to explore both how and why techniques vary and why it's important to you.

Let's start with a quick look at where technique fits into the greater world of paint polishing variables, and then we'll break down that term "technique" and look a bit more in depth into how and why it matters.

10 Things That Impact the Results While Machine Polishing Paint

1. The tool being used
2. The product being used (compound, polish, etc)
3. Supplemental wetting agents
4. Buffing pad
5. Backing plate
6. Paint & substrate
7. User technique - the subject of this article
8. Environment
9. Time & expectations
10. User attitude

So technique is just one of several variables in the overall process, but we can break technique down to 5 synergistic variables that can be adjusted by the user. Why "synergistic"? Because these variables, all of which can be controlled by the user, are interdependent and interrelated - they all work together to impact polishing results. These variables are:

Tool Speed

• [*=2]variable speed settings will alter cut of any pad/product
  [*=2]the lower the speed, the less the defect removal
  [*=2]the higher the speed, the greater the defect removal
  [*=2]high speed generates more heat on the paint
  [*=2]high speed causes more swirls
  [*=2]low speed indicates more control
  [*=2]low speed generates less heat and fewer swirls
  [*=2]rotary speeds are measured in revolutions per minute (rpm) while DA speeds are measured in oscillations per minute (opm)
  [*=2]Meguiar's recommends never spinning a rotary at speeds in excess of 2,000 rpm when polishing paint
  
  

Arm Speed

• [*=2]defined as the rate at which the tool is moved across the paint
  [*=2]slow arm movements allow for more time spent buffing in a given spot, and defect removal is increased
  [*=2]fast arm movements allow for less time spent buffing in a given spot, and defect removal is decreased
  [*=2]fast arm movements can also increase the risk of holograms
  [*=2]faster arm movements give a false perception of working faster

Slower arm speed

Faster arm speed

Downward Pressure

• quite literally, how much pressure the operator is applying directly over the pad
• the lower the pressure, the lower the rate of defect removal
• the greater the pressure, the greater the rate of defect removal
• increased pressure will also increase heat generation, and the heat can rise dramatically and quickly, leading to the very real possibility of paint burn

Lower pressure - note how the backing plate is practically sitting on top of the pad


Greater pressure - note how the pad is now compressed under the backing plate and actually curling up over it

Pad Angle

• quite literally, the angle of the pad face relative to the panel
• "on-edge" buffing yields more swirls and provides less defect removal
  
• "on-edge" buffing gives a false perception of more aggressiveness/faster defect removal, mostly due to increased downward pressure being applied
• a flat buffing pad products less swirls and more defect removal

Pad flat to the surface


"On-edge" buffing

Application Area

• [*=2]this is the size of the area being worked for a given amount of product; also known as a work section
  [*=2]a larger application area provides....
  [*=3]less defect removal
  [*=3]less control
  [*=3]less consistency
  [*=3]potentially more swirls
  [*=2]a smaller application area provides....
  [*=3]more defect removal
  [*=3]greater control
  [*=3]greater consistency
  [*=3]less swirls
  [*=2]area size should be roughly equal to the shoulder width of the operator

Small area being worked

Larger area being worked

So now you have a clearer understanding of how different techniques impact the buffing process and how you can both minimize problems and maximize results by varying your technique. You may be thinking "but isn't there one ideal technique?" In reality you need some variation in technique at times, for a variety of reasons. Severity of defects, hardness of the paint, even the climate and customer expectations might cause you to adjust your technique from time to time. And with the tremendous variations in paint systems out there, if you do the same thing on every car every time, you will miss the mark half the time. The best detailers are able to adjust their process in order to address all of these variables, and they understand the impact of each change they make to that process. They're able to "read the paint" and adjust their technique accordingly.

Lastly, now that you can dissect buffing techniques you can watch others and better learn and understand what's actually happening. You can identify your own technique and adjust it with precision. Most importantly, you can expand your capabilities and improve your skills. No go out there and polish some paint.

********************

We would be terribly remiss if we didn't give credit to Jason Rose for his vast knowledge on this topic. Jason has travelled the world, literally, working with body shop techs and detailers in places as varied as Germany, Brazil, Australia, China and of course all over North America. He's seen every type of paint system imaginable, and he's seen every technique you can think of (and some you probably can't!!). His observations have allowed him to distill down the generalized techniques used in different parts of the world. To that end, for you really hard core fanatics who can't get enough info when it comes to detailing, we'd like to share the following observations on buffing technique from around the world, with a little explanation of each. A little disclaimer first - the techniques we outline for each geographic area are what is prevalent in each area in a body shop environment and are not meant to imply that everyone does everything exactly the same way. But there are definite differences in technique from one part of the world to the next. We also apologize for the graininess of the following images as there are captures from short video clips.



Asia


Tool Speed: medium to fast
Arm Speed: medium to fast
Downward Pressure: medium
Pad Angle: on-edge
Application area: wide
Overall Aggressiveness (scale of 1-5 with 5 most aggressive): 4

• Technique follows relatively softer paint
• Lots of paint defects
• Body shops tend to sand full panels
• Commonly used pad is large diameter foam

____________________________________________________________________________________________________

Western Europe


Tool Speed: slow
Arm Speed: fast
Downward Pressure: light
Pad Angle: flat
Application area: small
Overall Aggressiveness (scale of 1-5 with 5 most aggressive): 1

• Least aggressive technique in the world
• Technique follows high tech painting processes and progressive polishing products and tools
• Body shops tend to do only spot repair sanding
• Commonly used pad is small diameter foam with thick backing plate

____________________________________________________________________________________________________

South America


Tool Speed: fast
Arm Speed: fast
Downward Pressure: light
Pad Angle: heavily on edge
Application area: very wide
Overall Aggressiveness (scale of 1-5 with 5 most aggressive): 3

• Technique follows old school practices and lack of high tech compounds in the market
• Lots of paint defects
• Body shops tend to sand full panels
• Commonly used pad is large diameter wool

____________________________________________________________________________________________________

United States


Tool Speed: medium to fast
Arm Speed: medium to slow
Downward Pressure: strong
Pad Angle: slightly on edge
Application area: wide
Overall Aggressiveness (scale of 1-5 with 5 most aggressive): 5

• Most aggressive in the world
• Body shops show a mix of spot repair and full panel sanding
• Commonly used pad is large diameter wool

[davey g-force]

Re: Rotary Buffing Techniques - How Variables Impact Results

Great and very informative article Michael - thanks for that!

fast arm movements can also increase the risk of holograms

I must say, this comment really surprised me!

And the observation about Europe having the least aggressive technique in the world certainly correlates to why M101 has such a high level of cut.

[greg0303]

Re: Rotary Buffing Techniques - How Variables Impact Results

Super helpful and thoughtful article, Mike.

The final results are in our own hands with technique playing a big role in the whole process.

Quick review of the preferred methods around the world is very interesting. No wonder Meguiar's offers some products/ accessories just for specific markets.

[juliom2]

Re: Rotary Buffing Techniques - How Variables Impact Results

On the money!!!!!Great post!!!!

Many friends were missing some rotary overview!!!!!.....
Awesome Comprehensive guide to work and achieve beautiful results.

[Michael Stoops]

Re: Rotary Buffing Techniques - How Variables Impact Results

Great and very informative article Michael - thanks for that!



I must say, this comment really surprised me!

And the observation about Europe having the least aggressive technique in the world certainly correlates to why M101 has such a high level of cut.

Fast arm movements are often coupled with on-edge buffing because, in the hands of an unskilled operator, it gives the impression of working faster. But more often than not those two combined yield results like this:



Now, if you're compounding with a wool pad and an aggressive liquid at a fairly high speed because the defect removal process requires that, odds are you're going to get some level of holograms, no matter how light. But a wool pad and aggressive compound at fairly high speed shouldn't be your last step. Unfortunately for the owner of this car, it was the last step.

As for the aggressiveness of M101, that is in part due to the workflow common to body shops in Europe, but also to the chemistry of aftermarket paint in Europe. Obviously a car built in Europe and sold to other markets is going to have the same factory paint whether that car ships to North America, Australia, etc. But the big difference comes in aftermarket paint, which is dramatically different from factory paint. And aftermarket paint in Europe is vastly different from aftermarket paint in the USA. That played a huge role in the development of M101.

[Ralph III]

Re: Rotary Buffing Techniques - How Variables Impact Results

It's a great article but I do not agree fully with what is stated. In regards to my background, I managed a detail business for 14 years and in those years buffed well over 10k vehicles.

I would like to state the following.

A) I never buffed with my pad completely flat! You simply get a lot of pad bounce or chatter because you have opposite edges attempting to move in different directions. You should angle the pad ever so slightly in order to avoid chatter. The pad is near flat but you do not get the bounce. I think a lot of professionals do this instinctively but describe it as being fully flat when it in fact it isn't.

B) "On Edge" buffing does yield greater/faster correction ability! It does so because you are isolating a specific area (scratch). The amount of pressure applied and angle will vary depending on how the paint is reacting. I have made some serious correction of scratches on paint with use of a foam pad and this technique when painting the automobile wasn't an option. You must be highly attentive when doing so though as it can easily burn paint.

Yes, it will create swirl marks but you will correct that issue after you have corrected the major issue (scratch) to your satisfaction. It's really all one process. I would put it on edge to get the paint to flow over the scratch (different angles) and then go "flat" in correcting any swirl issues. The former is a more isolated area whereas the later is a much larger area.

Yes, you could possibly get the same results by keeping the pad flat and using your compounds but... 1) it will take longer and time may be a factor as it was for us, 2) you will be doing a heavy correction on a much larger area which isn't desired. It's better to do a heavy correction on a smaller area (scratch) and the lighter correction of the rest of the paint, IMHO. It's detrimental to remove paint or clear coat where such isn't really necessary.....

Other than that, the article is very good.

God Bless,
Ralph