There are eight factors that rate in foam quality; Density (or rebound), Compression, Sag Factor, Fatigue loss, Hysteresis, Tensile, Elongation and Tear resistance.
However,it is compression, hysteresis, and tensile strength that have the most to do with the abrasive or cutting ability of a pad.
These factors all play into how much give the pad has under pressure and torque. Density, (not a measurement of compression) has a lot to do with the amount of polish the pad will accept (see also pores per inch (PPI)) a pad that holds a good volume of polish allows the polish to do the cutting job instead of the pad.
Velocity and applied Pressure are also factors that affect a foams abrasive (cutting) ability, all of these factors affect the flexibility of the foam under pressure and torque
The abrasion or cutting ability of a foam pad relative to its composition, the work is approximately distributed, 60% product, 30% foam composition (density, pores per inch (PPI)) and 10% pressure applied and/or speed of rotation or oscillation.
Pad Dependency
All abrasive polishes are ‘foam pad and applied pressure dependant’ as far as their paint correction abilities are concerned. Any abrasive / pad combination is reliant upon its most abrasive component.
If we consider the Lake County (LC) White foam (50 PPI) polishing pad as the baseline; any polish used will derive help from the abrasive abilities of the foam. Then consider the LC Blue (70 PPI) finishing pad has no abrasive ability and will contribute nothing to the cutting capability of a polish.
What is derived from this is that a polishes abrasive ability can be ‘fine-tuned’ by using different combinations (abrasiveness) of polish and foam (the same thing is true of wool pads) and of course differing the amount of downward pressure (10-15 Lbs is the usual range) applied will also have an effect on the abrasives capability
Different pad / product combinations (least abrasive pad / polish first)
a) Base pad/product (least abrasive pad/product) if this combination does not provide the desired results, increase the aggressiveness of the technique or product selection.
b) Step-up 1 - using the same pad with a more abrasive product
c) Step-up II – use a less abrasive pad and the same product as used in step-up I
d) Step-up III- using the same pad with a more abrasive product
As can been ascertained from the above the total abrasive ability of a polish/foam pad combination is subject to many variables, the polishes abrasive ability is just the starting point
Factors that increase abrasion ability
• Increased speed (Velocity)
• Increased pressure (Compression)
• Use smaller pad(Reduced surface Area)
• Using a slower panel transition speed (Increased surface contact time)
• Reduce the working area
The key to the polishing process is to know how the paint will react with each pad/polish combination you consider using. You must know your product and what its capabilities are before using it. This is why a ‘test’ spot is so important.
The factors that affect the outcome -speed, friction (kinetic energy) applied pressure, foam pad actual surface contact area, pad grit number (abrasive ability) amount of surface lubrication available, the surface area and heat conductivity of material
All pads have a performance cycle, meaning you will get the desired results only to a certain point on that curve. The point of declining performance is typically reached by polish/compound pad being overloaded with the product; you should always be able to see the individual cells or texture of the pad, with proper, regular cleaning pad overload can be avoided.
Clean (or replace) you pads frequently: pads are easy to clean; the slotted pad face actually makes it easy to clean. Do not use the same pad to apply differing products as cross contamination will reduce the effectiveness or completely negate their purpose altogether. A new or freshly cleaned pad must be used with each type of car care product.
Pad cross contamination
• Clean and/or replace pads as often as is necessary; a clean, primed and seasoned pad will enhance the abrasive abilities of the compound/polish and make the process not only more efficient but less time-consuming.
• Do not use the same pad to apply differing products as cross contamination will reduce the effectiveness or completely negate their purpose altogether.
• If you thoroughly clean pads right after use you shouldn’t have any problems with contamination from different grades of polishes or compounds. However do not use the same pads for different sealants, or use a pad that has applied a sealant as a polishing pad or vice a versa.
• Some polishes or sealants may be difficult to completely remove product residue. It is good practice to use a new or freshly cleaned pad with each type of car care product.
Notes:
1. It is preferable to polish 2-3 times to restore the paint film surface than to use an unnecessarily abrasive polish/foam combination
2.Wool pads are not recommended for random orbital machines (Porter Cable 7424, etc) as wool pads nap/fibres work more efficiently with a centrifugal motion Foam cutting pads tend to be much’ stiffer’ than wool fibres and thus will transfer the movement of the machine to the paint surface more efficiently than a comparable wool pad on an orbital polisher
3. The Flex 3401 is the exception to (1) above as the forced rotation supplies a centrifugal motion to the pad
4. Natural wool is most aggressive - 50/50 wool/acrylic blends intermediate - lamb’s wool the least aggressive
5. Always use the least aggressive product first, evaluate the surface, then only if necessary `step-up' to a more abrasive product and/or pad.
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