Just bought one and used for the first time tonight. Worked only on the trunk to give it a go. At first, it seemed surprisingly smooth, I was impressed...but a little bit into it, as the pads began to saturate, the vibrations got noticeably stronger. I assume this is normal as the pads get heavier, but it seemed a little too much.
What you're describing does sound normal.
Something to watch for...
As your pad become wet with product, it is possible and even likely that the pad can shift around on the backing plate, as in 'move" so that it is no longer "centered". This is especially true when doing correction work and anytime you're buffing a thin panel or going up on edge to buff a tight area.
In a perfect world, you want a LOT of pads. A perfect world we be one pad per panel. A 2-door car has 9 panels. You can certainly get away with less but the best results when doing correction work or polishing work comes from changing to a clean, dry pad often.
As the saying goes... a picture tells a thousand words...
Most people probably don't notice but for the last 3-4 years, every time I detail a car I pile up all the pads I use and include them in the pictures I share that document my work. I do this on purpose as a way of sending a visual message to people new to machine polishing that to buff out a car you need more than one correction pad, one polishing pad and one waxing pad.
Here's an example, look at the number of pads on the roll-around tray.
Review: BLACKFIRE One-Step Cleaner/Wax by Mike Phillips
Here's another one... from 2016
How to use Griot's Garage to detail your car - A detail job Richard Griot would be proud of!
The numb of pads and the TYPE of pads for these two car detailing projects are different because for the Chevelle I used a one-step cleaner/wax, thus I only needed and used one type of pad. For the 1970 Cuda, I used the traditional multiple-step approach of using a compound, a polish and a finishing wax, thus different pads for the different products and procedures.
The BIG PICTURE is anytime I share a write-of from my work I also telegraph a message with the pictures. They mean something just like the words used in the write-up.
Considering I have nothing to compare it to, how can I tell if this is normal or if I may have picked up a defective DA?
It's normal.
The panel I worked on isn't terribly large, about 6 square feet and I broke it up into 4 sections...between the compound and the polish, I probably worked the tool for about 30 minutes...45 minutes later my hands still feel a little tingly(super scientific, I know). It feels like this thing would kill me if I tried doing the whole car in 1 day.
That's normal too.
If you read enough you'll eventually find a lot of people are sensitive to the vibration created by tools like this, that is free spinning 8mm orbital polishers, this would include not just the Griot's but the Porter Cable 7424 and all the Porter Cable variations of this tool and any copy of the Porter Cable, of which is what the Griot's is. Also the Meguiar's G100, G110, G220 and MT300, the HF ROP, the DAS 6, etc., etc. etc. For the most part, any random orbital polisher sold into the car detailing world that is a 8mm orbit stroke length free spinning polish is a copy of the Porter Cable wood sander.
See my article here,
The Free Floating Spindle Bearing Assembly - The Story Behind The Story...
Here's an excerpt from the above article but TONS of actual useful info in the article even today as I write for the future, not the moment....
Enter the Porter Cable DA Sander
That's right, I said
sander! The Porter Cable Dual Action Sander is the tool that became the
Tipping Point that was the driving force behind the average person switching from working by hand to working by machine.
The Porter Cable Dual Action Sander with Wood Dust Collecting Attachment for Sanding Wood
Also, after just doing the trunk lid, I completely understand why most talk about going to a 5" plate/pad, so I'll be ordering a 5" and 3" before I tackle the rest of the car.
I don't know if you found and read this article, probably one of the article I share the most in the last year and this year, but it explains the backing plate size dilemma and also foam versus microfiber pads plus so much more....
Here's what you need to get into machine polishing - Recommendations for a beginner by Mike Phillips
Tonight I used what the tool came with, a 6" plate and orange pad for the compound, and I bought a black microfiber pad that I used for the polish.
I'd say their "orange" foam pad is closer to either a polishing pad or a "light" cutting pad, it's pretty safe. Normally you would cut with a microfiber pad and finish with a foam pad as fibers can and will cut the paint and leave what is called micro-marring. Foam will remove micro-marring, thus the order is fiber then foam. The huge factor the decides whether or not you get and/or see micro-marring comes down to the paint and the abrasive technology you're using.
Would stepping down to a smaller plate/pad increase or decrease the amount of vibrations from the tool?
Thanks.
I'd say it would tend to decrease it a tick but not enough to be a deal maker or deal breaker.
Hope the above helps....
