Slower or Faster speed with a small pad?

[Irkie500]

I need to correct a scratch in a tough spot that will require me to break out the 3 inch pads. I have only used them for LSP`s so I am not sure on pad speed here. Ill be using the PCXP with 3 inch LC Flat pads. Is speed 5-6 acceptable or should I stick with 4?

For anyone who is curious the scratch is at the bottom of a front fender along the side skirts right near the front door seam, going to be a pain.

Thanks!

[LawrenceSA]

I think 5 to 6 is too high.... probably around speed 4 should be good.

[TroyScherer]

I vote "Whatever speed is required to keep the pad moving and doing the job." A slower speed should also mean less heat. And the less heat the better.

[Legacykid]

I go lower speed , can always adjust as needed

[Accumulator]

I generally use the same speed (i.e., 5 or more) with the smaller plate/pads, but IMO it`s one of those things where you oughta go by your own experience as YMMV seems to apply.

[Merlin]

Slower speed is better on a small pad.

[Migue]

Speed 4 will give you a good spin on that machine and pad size combo. I use my PC with 3" pads only and have done a few scratch repairs with it, but since I`ve had more experience with it, I`ll run it at speed 6 for one pass or so(monitoring surface heat) then turn it down to 5 or 4 sometimes.

[Irkie500]

Thanks everyone! I just needed to double check as I could have sworn I read something that said because of a smaller pad you have less surface area, thus less heat is generated, thus more speed can/should be used.

[Migue]

Just start with the speed that gives you a steady spin like mentioned above ,and check your results often then adjust accordingly.

[JustJesus]

Didn`t Todd Helme write something about this?

Food for thought: If slower speed would be better for a smaller pad, why would the speed range of the PE8 be 1300- 3900, while it`s full sized big brother, the PE14, be set up with 600- 2100. Keep in mind the PE8 was designed with smaller pads in mind (1"- 3").

Maybe it`s different for DAs?

[LawrenceSA]

The way I understand it is that with the smaller diameter pad on a DA there is less surface area and weight of the pad and so it will actually cut more than the same type of pad in a bigger diameter at the same machine speed. This is why you can turn the speed down a bit in comparison.

On a rotary, when you increase the pad diameter, the outer edge has to travel further with each revolution, and thus it has to spin faster, creating more cut.

[Stokdgs]

The way I understand it is that with the smaller diameter pad on a DA there is less surface area and weight of the pad and so it will actually cut more than the same type of pad in a bigger diameter at the same machine speed. This is why you can turn the speed down a bit in comparison.

On a rotary, when you increase the pad diameter, the outer edge has to travel further with each revolution, and thus it has to spin faster, creating more cut.

This is absolutely correct !

I know it has been debated on and on, but I am absolutely positive that the outer edge of a spinning disk will always be going faster than the center of that spinning disk..

Here is a more graphic example -
On the older Snapper lawnmowers - the ones that had a spinning disk driven by a belt that was connected to the engine, there was a rubber disk that was mounted vertically on top of that spinning disk, that was controlled by a lever at the end of the handle.

The rubber disk was connected to the rear wheels through a differential that just drove them together - like rear wheel drive -

When you moved that rubber disk across the spinning disk, that engaged the mower wheels, the mower took off..

When you moved that rubber disk to the EDGE of the spinning disk underneath, the mower speed was the Fastest....
When you moved that rubber disk to the Center of the spinning disk underneath, the mower speed was the slowest...

The speed you need and pressure you apply to that particular scratch, combined with the pad type and compound/polish used will never be just "this speed and pressure", because there are too many other variables to add to the equation..

But as has already been stated above, the smaller diameter pad will be spinning faster than a much bigger pad at the Center because of the small diameter...
Good Luck !
Dan F

[Stokdgs]

Didn`t Todd Helme write something about this?

Food for thought: If slower speed would be better for a smaller pad, why would the speed range of the PE8 be 1300- 3900, while it`s full sized big brother, the PE14, be set up with 600- 2100. Keep in mind the PE8 was designed with smaller pads in mind (1"- 3").

Maybe it`s different for DAs?

Great Question !

Well, for sure D/A`s will never rotate as fast as a Rotary and are not direct drive like a Rotary, so if you want faster pad rotation, you have to turn them up...

I don`t know why that little Flex PE8 starts out at 1300 rpm, as I never start out at that speed because I hate to fling material all over the place for one, and secondly, I have found after many moons that slower speeds with a big Makita 9227C work just great for me..

I can put a lot of downward pressure on the paint if I need it and there is less heat build up, so the pad, compound or polish, and the paint have a longer time getting acquainted with each other, and everything breaks down together so well that I usually let the pad clean up anything left so when done I have very little to wipe off the paintwork, thereby lessening another opportunity to introduce defects into the finished product...

I use mostly DAT compounds anyway so I want them to break all the way down and give me the best correction and clarity and gloss (with a good pad designed for that), so starting off at speeds over 1,000rpm is just not a good way to accomplish the results I get for my needs...

Everyone will have a different way to get to the same place - this is just how I get there...
Dan F

[4u2nvinmtl]

This makes me think of VVT transmissions...

[JustJesus]

...Everyone will have a different way to get to the same place - this is just how I get there...
Dan F

Good post, but this part was the best part!