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4 in pad w/ drill vs full size rotary



ive started my detail on my vette i just picked up a couple days ago, it has a bunch of swirls in it and i was using my flex on the hood. i got most of the swirls out but there are little specs in the paint that look like pits.


so i busted out my craftsman drill w/ 4inch orange pad w/ SHR and BAM after one pass it was all gone. i was amazed in that one particular area, it was perfect. i kept staring at it in amazement lol i was thinking if it was THAT easy to take out what the flex couldn't in 3 hours on the hood why not just get a makita or something like that. is there a big difference between a 9227c and a drill other than the size?


do i run more risk of causing damage? i know to be careful with it using less pressure and faster movement but it def. got me curious bc of the result i got with the 4 incher. it would save me ALOT of time it seems like

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I was curious about using 4" pads on a rotary and here is a response I got.


smaller pads concentrate the polishing area so yes you have a higher chance to burn paint, however if you keep the pad moving you should be ok. most use the 4" pads for certain areas like the A pillars or the window trim some cars have. Smaller areas that are harder to hit with the larger pads.you are not wrong at all they do cause more heat and more of a chance to burn through the clear, but if you keep the pad moving and you don't sit there polishing a small area for a while you should be good. now what i do with any pad with my rotary is shut rotary off for a second and feel surface temp, if its feeling a bit warm i wipe off residue and let panel cool before i do another pass if needed.


I say your fine, if your running the rottary anywhere between 1000 1700 rpm, but everyone else will say no. Do some research

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The risk of damage is substantially higher with rotary, so know that going in.


Also over larger areas, technique with rotary becomes much more important or you'll end up hologrammed all over.


It will get results faster b/c its removing more clear coat in less time, its the same reason its also much more dangerous if you don't know what you're doing.


Generally I work at very low RPM when working with rotary, the biggest mistake most people make is running the tool at full tilt and generating way too much heat.

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I think your question may be better answered by some simple physics. I know this basic principle really helped me a lot in my early days of learning the differences between the machines.


Large Pad + Porter Cable = Less Cut (Safest Combo)

Small Pad + Porter Cable = More Cut


This is because of the side to side random orbital motion of the Porter Cable. There is more movement closer to the center of the backing plate than there is on the outer edges. The hex cut design of the Adam's pads helps out a little by providing a little more aggressive cutting action since there is less motion going on at the outer edges of the larger pad.


Conversely, a rotary is the exact opposite:


Large Pad + Rotary = More Cut (Highest Risk Combo)

Small Pad + Rotary = Less Cut


Since your moving in a circle, the larger the diameter of the pad, the faster it's moving as you get farther away from the center. Do you get dizzier in the center of the merry go round or at the outer edge? Faster = higher heat = more friction = BURNT PAINT. Again, the hex cut design of the 4" focus pads help you out a little since on a drill, which is indeed a mini rotary, you get a little extra cutting power from the hex design.


Based on your initial question/post, I'd try the 4" pads on the Porter Cable. I have two 7424 on my shelf - one with each size backing plate and will use both when I'm polishing a car. The small pads on the PC provide a little more bite with nowhere near the risk. Hope that helps!


- Darryl

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