Back to the question: why did the pads perform so differently?
Pad comparison:
Both pads are designed for
final polishing, and neither pad is known to cause marring when used on delicate paint surfaces. The 7? foam pad is
taller and
larger in diameter than the 5.5? microfiber disc, which could potentially absorb some of the machine?s orbital motion via increased cushioning action.
The diameter discrepancy between the pads was pretty substantial. In general, a larger diameter pad offers improved stability as it glides across a surface. In other words, if the machine is inadvertently tilted one way or another during polishing, the pressure shift is more gradual. Subsequently, it is easier to regain control of the pad when its diameter is larger.
In addition, during that time, the pivot point (or fulcrum) does not receive as abrupt a concentration of pressure as it would on a smaller pad, so there would potentially be less scouring of the surface at the pivot point. These observations are perhaps hypothetical, yet sensible nonetheless.
Finally,
larger diameter pads feature
more surface area. But then, this is where our comparison gets complicated, at least when comparing these two pads. Before we compare these two pads, let's run some numbers.
The 7? diameter foam pad features 38.48 square inches of total surface area, while the 5.5? diameter microfiber pad features only 23.76 square inches of total surface area. That?s a difference of 61.9%, in favor of the larger pad. This means that if the same pressure is applied to the same machine, the smaller pad will have a larger concentration of weight and pressure placed upon it. This can change all sorts of things, including overall backing plate rotation when using a random orbital machine.
Additionally, a larger pad of the same type can be used
longer before it accumulates the same percentage of potentially damaging residue and debris. Looking at things another way, you can use a large-diameter pad longer before
cleaning is needed.
So far, it seems as though a larger the pad is the best choice for final polishing duties. Yet, we haven?t taken into account how the buffing liquids we use are built and designed to interact with the pad, nor have we accounted for the fact that the DA Microfiber Disc features
thousands upon thousands of fibers that are capable of holding loads of buffing compound and abraded paint residue.
In fact, if we were able to measure the surface area
in contact with the paint at any given time, I believe that once its fibers had packed together due to compression, the smaller DA Microfiber Finishing Disc would offer up a
huge surface area advantage. Perhaps, the difference would be a startling amount.
To be fair, we must also consider how the disc was prepared for polishing, and how well its cleanliness and fluffiness was maintained. Do you see where this is going? That?s right- we have way too many unknown variables to form a tenable conclusion. So, where does this leave us?
The short answer:
In this case, it?s quite likely that
initially, the flat-faced foam pad offered up more immediately usable surface area, thus keeping the pad-to-residue ratio lower than that of the microfiber disc. Perhaps it?s also true that the pore structure of the pad was able to store the damage-inducing paint remnants away. Maybe the abrasive grains were able to attach themselves to the pad only briefly? If so, abrading action would have been short lived- much shorter than we realized.
Finally, we should
at least consider the possibility that machine movements and applied pressures were more evenly dispersed across the panel, and pad face.
But then, this is all conjecture, hypothesizing, and theorizing. In short, it?s a
guess. We didn?t end up having the time to discuss things, nor do any structured testing. Conceivably, it could have been Mike?s polishing abilities!
After all, as of late, the glorious Mike Stoops has become quite the paint-polishing guru.
"Perhaps it?s not that at all. Maybe he?s not that good, but instead failed to realize that the foam pad shouldn?t have worked better?"
Oh, how that Professor Von Stoops loves a good joke. Isn?t that right, Mr. Mike?
The long answer:
Somewhere amongst the following 12,000 or so words is the
long answer. I?ve tried my best to be brief, but
obviously it didn?t quite work out as I?d planned. Regardless, I hope you?ll stick with it and read my best attempt at writing what I
know to be true.
At least it?s what I think I know.
PAD PRIMING, AND HOW IT AFFECTS POLISHING PERFORMANCE
My theory as to why pad priming works so well is based mostly in deductive reasoning and comparative analysis of polishing results. Comparisons were made using primed pads and non-primed pads, and by employing various application methods on all sorts of paint types.
It has been my experience that most times a better result is achieved by priming the pad with the buffing liquid as opposed to using a non-primed pad. Certainly this may have to do with the way I handle my polishing machines, manipulate their speed controls, time my polishing cycles, and apply pressures and angles to the machine. There are lots of other procedural issues to consider, too.
One thing is for sure- I am definitely able to see the effects that priming has on a pad by magnifying the pad using my Radio Shack Handheld Lighted Microscope (Carson Optical makes the microscopes for Radio Shack):
http://www.radioshack.com/product/index.jsp?productId=2179604#
http://www.carsonoptical.com/Pocket_Microscopes/Pocket_Microscopes/MM-100
While I typically prime the pad and use additional product for the defect removal process, I use a different approach for final polishing. Although I still prime the pad thoroughly at the onset of the polishing session,
I minimize the amount of compound applied to the pad by blowing the pad clean using compressed air prior to polishing. If I don't have air handy, I place the pad face into a microfiber towel and run the machine for 3-7 seconds, or until the pad is still moist but there's no obvious polish stuck in the pores of the pad. Then, I add small amounts of buffing liquid as needed. For delicate or hard to refine finishes, sometimes no added product is needed. Let?s discuss final polishing and prepping of the pad for final polishing after we cover some benefits and drawbacks associated with pad priming, using the buffing liquid as the primer.