Page 40 - Australaasian Paint & Panel Jan-Feb 2022

SANDING & DUST EXTRACTION TECH TIPS
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PAINT&PANEL JANUARY / FEBRUARY 2022
ARE YOU IN
THE RIGHT ORBIT?
3M’S GEORGE DISCALA SHARES TECHNICAL TIPS ON SANDING ORBITS AND WHY THE RIGHT EQUIPMENT IS VITAL.
A concern many technicians have when using larger orbit sanders is the impact it will have on the scratch finish. This con- cern is largely due to the old terminology of categorising sanders as “coarse or fine”. The orbit of the sander has been shown to have very little effect on the scratch finish of the abrasive. For example, if you are us- ing a P800 disc, it doesn’t matter which or- bit sander you use (2.5mm or 8mm). The final finish is still a P800 scratch. The big- gest difference will be the cut performance of the abrasive disc. The production in- crease of using larger orbit sanders far out- weighs any small differences in scratch.
LARGE ORBIT DRAWBACKS
A 2.5mm orbit sander is very comfortable to use, with little to no vibration, but also has very low cut-performance and will generally tend to decrease the perfor- mance of abrasive discs. Since the abra- sive disc has very little movement, unless effective dust extraction is employed, the abrasive will load and clog up more read- ily since the dust produced also has little movement and tends to be trapped under- neath the sander. Large orbit sanders do a better job of kicking out the dust from un- derneath the abrasive, limiting the amount of clogging on the disc.
While there are some drawbacks to go- ing to larger obit sanders, the advantages can often outweigh the differences. An 8mm orbit sander will have more vibra- tion than a 2.5mm orbit sander. This can be hard and fatiguing on a technician, but
I
T’S OFTEN PERCEIVED THAT
the sander of choice is de- pendent upon what part of the shop it’s used in. In some cases, this is true, but there is more to con- sider. Historically the orbit of a Random Orbital sander was referred to as “coarse throw” or “fine throw”. This has given the industry a false perception of what the im- pact the orbit has with respect to the per-
When a large orbit sander is used, the abrasive will be moved in a larger mo- tion allowing the abrasive to cut more. Similarly, when a small orbit sander is used, the abrasive will move in a small motion and cut less. Hence, the amount of orbit or movement has a direct rela- tionship to the cut performance of the abrasive. In fact, the cut from a large or- bit sander (8mm) is as much as two times when compared to a small orbit sander (2.5mm). When cut is increased, refinement speeds are increased as well. For example, when refining P1500 grit scratches with a P3000 abrasive, an 8mm orbit sander will remove the P1500 scratch twice as fast as a 2.5mm orbit sander. This increase in cut perfor- mance helps get vehicles out the door quicker and can significantly improve efficiencies in both the body and paint shop side of the business.
formance of an abrasive disc.
The assumption has generally been
that coarse throw or large orbit sanders are used with coarse grade abrasives, while fine throw or small orbit sanders are used with fine grade abrasives. How- ever, further investigation and testing has shown this to be an incorrect way to look at sanders and applications.
The orbit or “throw” of the sander is the amount of offset the counterweight moves when a sander is in motion.
If you are using a P800 disc, it doesn’t matter which orbit sander you use (2.5mm or 8mm). The final finish is still a P800 scratch.