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It's in the details Mod!
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Discussion Starter #1
Due to lots of confusion as to the Meg's DA MF system and the use of traditional DA's (Porter Cable 7424 & Griots Garage) and the forced rotation machines (Flex 3401) and rotaries, I thought I would post this here.

Here is a good expanation from Todd Helme....

Random Orbital DA's do not have a fixed rate of OPM's vs. RPM. Take any of the newer style DA's and run them at speed six (which is usually rated between 6000-6800 OPM). Press down VERY hard on the paint, to the point the pad stalls or almost stalls. If you press down just right you can get the pad to spin at a greatly slowed rate, like 1 time per minute. While the orbits will stall slightly, most of the slack/friction is taken up in the bearing of the machine. You have created a rate of 6800 (roughly) per rotation.

Forced Rotation DA's have a fixed rate. The orbit is actually driven by the rotation, so that if the rotation stalls, so does the OPM, and vice a versa. In regards to the Flex, you are correct. The Flex orbits ten times per rotation and this never changes. This is easy to verify, spin the pad 1 time around and count the orbits, it is always ten.

This means that at maximum speed the Flex is limited to 4800 OPM. (480 RPM x 10 orbits per rotation). Flex uses a 'unique' way of rating the machine, but if we are comparing apples to apples then random orbital DA's produce more OPMs and are less likely to have the OPM rate stall (since the motor is not responsible spinning the big pad).

Now with most polishing systems and with foam pads, the Flex is going to produce more cutting power because it is a forced system and correction is dependent on how fast the foam is moving across the paint. The combination of a forced, high speed rotation, and the orbital motion means you transfering more energy to the paint.

Things get flipped around a little bit when you use something like a Surbuf or Meguiar's DA microfiber system. The texure (little fingers or the microfiber tuft) of the pad makes it more efficent with the orbital motion than with a rotational motion.

When something is orbiting it is like moving your hand in tiny circles (wax on/wax off). This exposes ALL of the microfiber (or micro finger)'s sides to the paint. Since the abrasive grains in the polish attach to the microfiber, the increase in surface area (and the amount of abrasives working) means that most of polishing action is coming from the orbital motion instead of the spinning motion.

In fact too much spinning motion is a BAD thing (hence Meguiar's recommending a SLOWER speed for the DA system). This is because spinning the pad too fast will cause centrifugal force to pull the fibers outward and cause them to lay flat. Down you just have a standard sized pad vs. a pad that is using all of it's surface area (and far less abrasives are being used at a given time).

This is why many people are getting better results using random orbitals instead of forced rotation machines when using products like the Microfiber DA disks (or Surbuff's).

Hope this makes sense and clears up any confusion.
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