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VaderGT said:
no thats the 6" I wanna see the mini 3" vs the griot 3"
I own the Griots and 15 so I know how they perform to each other.
I want to see what makes it worth $200 over price of griots over something so specialized. I mean the 3" will be used on such a small portion of working on the car. I am sure my Griots with the 2.75" backing plate is far superior but its a larger unit that doesnt fit into tighter spots like the griots 3"
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I thought the consensus on the GG3 is that the motor is too weak to do any real work. I've never tried one - so I don't know. Would be nice if Griots would just put a stronger motor in their 3" polisher.
 
I have the Griots 3" machine and have gotten use to the fact that it is down on power. At SEMA I was given a chance to try the 3" Rupes on one of their test panels. I was blown away by the difference. I have used a friend of mines LHR75 and it's a great tool so now my problem is which to buy. If money was no object I would have both the units but that's not the case.
 
Todd Helme said:
Here is the thing.. the spin of the pad is caused by the weight of the rotating assembly (pad/backing plate/bearings) as well as the speed and length of the stroke.

The Rupes motor in the 21 and 15 is plenty strong enough... Try as you might, you cannot bog the orbital action of the machine (it has enough power to whip that weight (pad/backing plate/arm) 21 mm away from its center at a rate of 4000 RPM. That is significant.

The reason that the pad stalls on corners is because of drag caused by the large pad, the friction and the size of the stroke. If a larger stroke creates more pad rotation, how does it also stall it? Much in the way that 6th gear will give you a higher top speed but less acceleration... The long stroke doesn't build momentum quite as quickly...

That said, if you get some bogging on the edge of a body panel, don't lift! In stead press down more. Engage and compress the pad so that all of that huge orbital motion will be transferred through the pad. You may even pick up a slow rotation by pressing harder.
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Well Todd! Why didn't you tell me this months ago???? You were def more right than me(I could never be wrong! Just less right!). I just did this and you hit it on the head... Push harder it picked up rotation again. Always gotta have all the right answers gaaaaawwwwdddd I thought I sounded smart!!! Thanks for the tip you sir are the man! :yourrock:bow
 
Dear Jsmooth & Todd

Pushing down harder to pick up rotation is about the most counterintuitive thing I've ever heard.

I bet if that little nugget of information were included in the product directions or printed on the box, the fortunate people who received these machines would be much happier with them.
 
Swanicyouth said:
I thought the consensus on the GG3 is that the motor is too weak to do any real work. I've never tried one - so I don't know. Would be nice if Griots would just put a stronger motor in their 3" polisher.
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Dear Steve & Friends

Roshan (ihaveacamaro) made a YouTube video showing that the 3" Griot's can correct:

[ame=http://www.youtube.com/watch?v=zCb2Nk_Kz5w]Griot's Garage 3 Inch Can Correct Paint!! - YouTube[/ame]
 
Todd Helme said:
I'm not an electrican, nor am I even close to one. In fact, I hate electronics!!!!

That said, I have spoken to several motor suppliers in our industry, and the way they expressed watts to me is like this...

Watts is the draw, or the amount of power used. When talking about an engine in a car, this would be like the miles per gallon or fuel consumption. While a larger draw often mean more power, efficiencies also play a large amount in the output.

It is possible to have a 600 watt pull deliver LESS output then a 400 watt pull. Again, I don't know enough electronics to enter in the debate you reference on AGO, at all, but I did understand that part from some engineers in the tool industry.



Here is the thing.. the spin of the pad is caused by the weight of the rotating assembly (pad/backing plate/bearings) as well as the speed and length of the stroke.

The Rupes motor in the 21 and 15 is plenty strong enough... Try as you might, you cannot bog the orbital action of the machine (it has enough power to whip that weight (pad/backing plate/arm) 21 mm away from its center at a rate of 4000 RPM. That is significant.

The reason that the pad stalls on corners is because of drag caused by the large pad, the friction and the size of the stroke. If a larger stroke creates more pad rotation, how does it also stall it? Much in the way that 6th gear will give you a higher top speed but less acceleration... The long stroke doesn't build momentum quite as quickly...

That said, if you get some bogging on the edge of a body panel, don't lift! In stead press down more. Engage and compress the pad so that all of that huge orbital motion will be transferred through the pad. You may even pick up a slow rotation by pressing harder.



Pad rotation has nothing do to with power (well it does, but not in this case). The Rupes 21 will keep operating at its maximum of 4000 OPM until a LOT of pressure is applied (you will hear it audibly stall). You can get the same effect (usually easier) on the Griot's.

Neither machine controls pad rotation directly by the motor, each uses a free spinning bearing. It's just a characteristic of the large stroke and pad dynamics.

That said, the Rupes Duetto has less power than the Griot's and will easily out perform, at least in every circumstance that I have tried thus far.
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Excellent points. I'm currently using a PC 7336 with no issues and a 5 1/2 in pad to grind down fiberglass with 40grit. I have not had issues with bog down. Yes I could step up but will not put my paint tools at risk of contamination. The PC's were designed for wood working which is much more grabby than paint. It's worth the time to figure out where and when to apply pressure at what angle. They are slowed down compared to the rotary but knowing what angle to apply pressure makes them very capable.
 
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