Flex vs. Rupes

The throw (or eccentric offset) [: Centripetal force is a force that makes a body follows a curved path: it is always directed orthogonal to the velocity of the body, toward the instantaneous centre of curvature of the path

If you are a professional detailer you will probably have both machines, but the Flex® 3401 (the rotation rate is 1/10 of the orbit rate) is definitely going to speed up the correction process. (OEM) production line paint finishing and correction use a large eccentric offset machines. Flex® Dual Action Machine Polishers are designed and built in Germany, they are the preferred choice of Porsche Body Shops and RUF Automobiles GmbH.

Speed and efficiency is the strong point of the forced rotation of the Flex®. It’s really easy to handle, and the power of the Flex with curved vertical panels actually resulted in a substantial decrease in detailing time since the pad never stopped spinning. A slightly stiffer baking plate along with Menzerna polishes, Lake County Hybrid pads are an ideal polish/pad combination

The Rupes has a large 15 or 21mm eccentric offset and has an indirect drive, making it virtually impossible to cause a strikethrough [1] on the paint. The Flex 3401 has a standard 8mm eccentric offset and uses a direct drive motor, allowing the user to apply more downward pressure.

 When polishing you shouldn't have to apply heavy pressure to the point where the Rupes would stall and the long throw would allow the polishes and compounds to work better as it abrades the surface. All that is required with either machine is that the pressure is sufficient to compress the pad (but not flatten it)

Use the Rupes pads and a Metabo 624064000 Backing Pad

Notes

1.        Speed, kinetic energy (friction), applied pressure, foam pad actual surface contact area, pad and polish / compound grit number (abrasive ability) amount of surface lubrication available, area being polished, and material (paint, especially paint edges, plastic, metal, etc.) heat conductivity of the material being polished

The above will, given the right circumstances, 'friction burn' (strikethrough) a paint surface wither it be a rotary or an orbital polisher; the operative word here is excess friction

2.        As opposed to paint burn, the cause of which is the localized and excessive use of kinetic energy (friction heat)