View Full Version : Speed question....G100 vs rotary....

Nick Chapman
Dec 16th, 2006, 07:24 AM
If you have the G100 set on speed 5, what would be the equivalent speed on a rotary? I know they are 2 different beasts, but what speed on the rotary would give the same results of a G100 set on speed 5? Same pad, same product.

Dec 16th, 2006, 08:43 AM
If you use a number dial rotary buffer, like the G100, if set at 5 you would be probably working like at 2500-2700RPM which would kill the paint instantly with a bad move and especially when compounding with a wool pad.

as far as i know, no professional care care product manufacturer recommends speeds above 2000RPM's.

I've never used a PC, but I'll get one this christmas as an obligatory self present :LOLOL: however, i've seen that speed 5 can remove up to medium defects with M83, so your equivalency to a rotary starts from 1200RPM and ends in 2000RPM.

if you're doing mild polishing and you're not very familiar, start with 1200RPM. if you're familiar, do your jobs with 1400RPM's and medium pressure.

if you're familiar and want to do nice polishing with more defect removal capabilities, step to 1800RPM and medium pressure too.

just remember the PC principles: keep the buffer moving and work your product "wet"

you can also check the first or second post (don't remember which one is it :P) which tells you the recommended pads and speed ranges for meguiar's products. if you work with 3M products, set your standard to 1800RPM's (recommended buffer speed for compounds and polishes)

Hope this helps.

Nick Chapman
Dec 16th, 2006, 09:15 AM
Thanks Chex!

I've got both the G100 and the Makita rotary, and no matter how many times I either one of them, I'm still learning. I just bought the Makita not too long ago, and I'm loving the results I get from it combined with the G100.

What I'm looking for is if I use the G100 on speed 5 with 80 Speed Glaze, it would be the same as using the rotary with 80 at xxxx rpm's. Does that make a little more sense?

the other pc
Dec 16th, 2006, 01:07 PM
If you have the G100 set on speed 5, what would be the equivalent speed on a rotary? ....There is no such thing. Since the two machines work in very different ways you can’t directly compare them that way.


It might possible to compare one specific aspect of operation at two different speeds, total material removal rate averaged over the entire worked area for example, if all other factors are held constant; paint, product, pad, downward pressure, arm speed surface area covered, overlap pattern, etc, etc. But everything would be totally different if you changed even one of them.

Of course in the real world of actually working on cars you’d never change just one piece of the overall puzzle.


Nick Chapman
Dec 16th, 2006, 04:12 PM
Hmmmm, let me try another approach. If you worked 80 in with a PC say 4 passes. At what speed would the rotary give the exact same results in the finish?

I know these 2 are entirely different machines, and I'm not looking for an RPM comparison. What I'm looking for is a point at which these two machines would give the exact same results on the paint's finish. PC on speed 5 and a rotary on xxxx rpm's.

the other pc
Dec 16th, 2006, 04:30 PM
What I’m saying is that that speed is different for every paint, every pad, every hand pressure, every arm speed and who knows what else.

You may never get the exact same results in the finish. You may be able to remove paint at the same rate but still get a different finish characteristic.


Dec 16th, 2006, 05:01 PM
maybe (can't precise the result much because i've never used a PC) I would say one pass with a rotary @ 1400RPM woud be an equivalent to two passes with the PC @ speed 5.

however if you did a pass with the rotary first, and with the PC second, you would get superior results and with a little or no swirls: a thing that is pretty tough to acheive using a rotary only.

Nick Chapman
Dec 17th, 2006, 04:32 AM
Ok, thanks guys! Thats the info I was looking for.

Dec 17th, 2006, 04:41 AM
If you were using the same product and pad, the rotary would typically be much more effective/agressive at defect removal even at it's lowest speed, compared to the PC at any speed. But at the same time I find that the rotary leaves a nicer finish, if you are able to avoid holograms/buffer swirls. This again depends on the actual paint, product, pad, speed and technique you are using etc. For the PC it takes a lot longer to properly break down the polish, so the work time between the two machines is also very different.

I really don't think you can compare the two machines like that. Often it might take something like #83 on a polishing pad with the PC, to have the same defect removal ability as say #80 on a polishing pad with the rotary. But between these two combos, the rotary would leave a much nicer finish.

Each machine has it's purpose. IMO the PC wins on ease of use and safe operation. The rotary wins on speed/effectiveness and the finish it leaves behind.

Nick Chapman
Dec 17th, 2006, 05:07 AM
This is just something I was curious about. As I am just learning to use the rotary(3 complete cars down now), I was just looking for info on when to actually break out the rotarty on a car.

Say if I do a test spot on my hood, and it takes 2 passes of #83, then 1 pass of #80, I would know in my head that I could achieve the same results with 1 pass of #83 with a rotary on xxxx speed, then move on to the PC for 1 pass of #80.

Not trying to be difficult, just picking your brains :D

Dec 17th, 2006, 07:45 AM
Yes, I'd say that if 1 or 2 applications of #83 on a polishing pad with the PC doesn't remove the defects, then it's time to bring out the rotary.

Then again, I myself always start out with the rotary, as I don't have the patience/time for defect removal with the PC, and IMO the rotary leaves a (slightly) better finish :)

Nick Chapman
Dec 17th, 2006, 08:00 AM
I agree. While I'm still learning how to properly use the rotary, I can already see the benifit of using it. It does give a better overall look to the vehicle after you've followed up with the PC.

Dec 17th, 2006, 08:23 AM
Bingo, i think that'll be the BEST combination,i only have a rotory i used 06 black focus, plan on getting a pc soon.Even tho it's using 2 machines the end result could or should be flawless.Todays paints to me are different than befor when bc/cc first came out,just my thoughts i wonder if anybody els'e notice's that? or maybe it's just me! GOOD LUCK!