The Fundamental Variables of Paint Polishing:
Pt 5 – Arm Speed
By Christopher Brown of OCDCarCare Los Angeles – OCDCarCare.com
Arm Speed is the rate at which a machine polisher is moved over a working section.
Moving a polisher quickly over a defected area does not accomplish more correction; it actually perform less.
Rapid arm speed is an archaic methodology carried over from a time when rotary buffers lacked variable speeds motors. Back then, it was a necessity to move a machine rapidly over a working section for safety because the forced rotation, held in a single spot for sustained periods of time, would result in an easy burn through of the paint.
Contemporary Concepts Regarding Arm Speed
In modern paint correction, utilizing a dual-action polisher; the machine, pad, and correction liquid perform the heavy lifting. This is ideal since modern machines are more precise and consistent than ever before.
The machine still needs a foreman; whose job is to direct how the machine operates on a particular job. A detailer’s eyes and arms are this foreman. The eyes stay ever focused, evaluating the results of each process. The arms guide the equipment over the working section at a rate that is optimal to maximum correction to that paint system. In a word, this rate of arm speed is generally—SLOW.
A Rough Guide for Arm Speed
Using a Dual Action Polisher, the starting point for arm speed is moving a buffer at a rate of 1 inch per second. This may seem incredibly slow, however it allows the MACHINE, PAD, and PRODUCT to do their respective jobs. This rate may be even slower for more heavily defected areas.
Remember (for arm speed) in paint correction: Slow and deliberate passes win the correction race.
How Slow Arm Speed Functions to Better Correct Paint Defects
Slow arm speed allows the pad face and correction liquid ample time to engage defects, allowing for sufficient correction. At its core; paint polishing is the process of moving a form of liquefied sandpaper over paint to remove defects. A surface defect (scratch) is MUCH bigger than the abrasive grit contained within a buffing liquid.
For comparison, imagine the size of a ditch, versus the size of a golf ball. The tiny golf balls (abrasive particulates) of a compound or polish cannot wear down the ditch (scratch) on their own.
However, when golf balls team up with one or two thousand of their buddies, and given strict orders to attack the defects, (slow arm speed) they can do some serious, and controlled, refinement. Often times, this little army of buffing particles can completely decimate many larger scratches. And, with deep uncorrectable defects (beneath the clear coat), the mini grit army can greatly minimize defects to the point of being barely noticeable. Deeper scratch appearance is improved through the rounding off the sharp edges of scratches.
Heat is the Byproduct of Slow Arm Speed
Since slow arm speed allows the pad and correction liquid ample time to correct defects due to increased friction, it does create one immediate and significant byproduct — HEAT.
As mentioned earlier, paint is a porous and catalyzed structure, and therefore is very sensitive to quick mechanically generated heat. When modern paint technology is paired with a substrate which does not disperse heat well, such as plastic, fiberglass, or carbon fiber, heat build-up can occur very quickly.
Therefore heat ALWAYS needs to be monitored, no matter the working section substrate material. Paint Dynamics and substrate type play a huge role in the rate at which a working section builds or retains heat. Therefore, arm speed can change from section to section based on many factors. Just because a procedure works to correct paint on the majority of the vehicle, does not means it works everywhere.
Closing Remarks About Arm Speed
Arm speed which maximizes the machine, polishing pad, and abrasive capabilities to correct defects with the least amount of aggression and heat generation is the goal. This procedure allows for maximum defect removal, consistency, and effectiveness while minimizing potential problems created by over aggressive methods. For the best and most efficient results, detailers must be able to accurately deduce defects, paint dynamics, and substrate types to accurately pair tool, pad, and correction liquid. These choices impact arm speed and therefore influence the overall rate of defect removal.
© Christopher Brown – OCDCarCare Los Angeles – OCDCarCare.com – 2013
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