Counter weight/backing plate concern

uziel5000

uziel5000

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OK so the more I read, the more I want to get on these. One question though...

From what I've read, the PC comes with a counter weight for a 6 inch backing plate. This means I would have to buy a 6 inch backing plate plus 6.5 inch pads to use it out of the box. Right? I keep reading about people recommending 5 inch plates or even smaller but it's not clear or don't mention anything about buying another counter weight? Is this necessary I just want to make sure I get what I need. Thanks in advance.
 
You would just need to get 6.5" pads to use with the backing plate that it came with. People recommend switching to a 5" backing plate, and 5.5" pads to give you more power and get into tighter spots if i am not mistaken. I am not sure if that is the only reason though.
 
I have a GG polisher and switch regularly from 3 inch to 4, 5, 6 inch pads and backing plate. I've never noticed a vibration issue caused bu not changing counterweights.

Bill
 
The PC comes with a backing plate and a permanently mounted pad. So unless you buy a kit you must buy a backing plate to be able to change pads. If you do a search you'll see most recommend a 5" backing plate with 5.5" very thin pads like the Megs thin pads because the PC doesn't have the power/torque to handle 6.5" pads. 5.5" pads are easier to work with, more effective and cost less. No need to change or worry about the counter weight.

You might want to consider the Griots Garage polisher--it has much more power/torque than the PC and a lifetime warranty. Equipped with a 5" backing plate and 5.5" pads there isn't anything it can't handle.
 
The counterweight is meaningless for how we use the PC. When I started the PC would come with the 5" counterweight, and the places like Autogeek would sell the 6" counterweight so we could all change them. The counterweights are for using the machine as a sander, as has been stated it doesn't really make any difference for how we use the machine.
 
If it is useless, can the counter weight be removed when polishing with a 5" backing plate or smaller?
 
lane5515 said:
If it is useless, can the counter weight be removed when polishing with a 5" backing plate or smaller?
Click to expand...

What I meant is the difference between the 5" & 6" counterweight is meaningless to our use. I wouldn't recommend removing it entirely, but go ahead and experiment and let us know.
 
I've not once had any difficulties spinning 6.5" pads on a PC. I even spun a 8" Megs W4000 wool pad on it. If you're stopping the pad you're putting too much pressure on it.
 
As far as the counter weight goes, I feel like the added weight of the 6" counter weight gives the pad some extra "swing". I tried running the machine without a weight installed at all, and that seemed to negatively impact pad rotation.

On the old school PC 7424 I like the 5" weight. On the XP I like the 6 - regardless of the pad size.
 
There's a 10 gram difference between the two PC 7424 counterweights.
 
dlc95 said:
I've not once had any difficulties spinning 6.5" pads on a PC. I even spun a 8" Megs W4000 wool pad on it. If you're stopping the pad you're putting too much pressure on it.
Click to expand...

^^ This. We read a lot about it here in the forums but I've used a PC and Schurhold which are about the same in power and never had a problem. I use 6" pads on mine with no issues. I would love to upgrade to a Flex but this isn't a job for me just a hobby and one where I'll polish friends and neighbors vehicles throughout the year but with two people and two buffers time usually isn't a huge issue.
 
pdqgp said:
^^ This. We read a lot about it here in the forums but I've used a PC and Schurhold which are about the same in power and never had a problem. I use 6" pads on mine with no issues. I would love to upgrade to a Flex but this isn't a job for me just a hobby and one where I'll polish friends and neighbors vehicles throughout the year but with two people and two buffers time usually isn't a huge issue.
Click to expand...

Well, I sold my Flex 3401, because I never used it. Every time, I was able to get more plate rotation with the PC than the 3401. I loved that thing too, but it was too much money to just be sitting around, or getting set aside in favor of the PC. Once I did a bucket truck with heavily oxidized fiberglass hood cover with the PC, I knew that was really the best fit for me.

I never have issues with pad stall. If it slows down, it's usually because I don't have the pad flat, or that I need to use a smaller pad to get into a mote complicated area.
 
dlc95 said:
Well, I sold my Flex 3401, because I never used it. Every time, I was able to get more plate rotation with the PC than the 3401.
Click to expand...

How can you get less plate rotation with a forced-rotation machine?
 
Setec Astronomy said:
The counterweight is meaningless for how we use the PC. When I started the PC would come with the 5" counterweight, and the places like Autogeek would sell the 6" counterweight so we could all change them. The counterweights are for using the machine as a sander, as has been stated it doesn't really make any difference for how we use the machine.
Click to expand...

Ding ding ding...We have a winner!

Seriously, changing the counter-weight for OUR application really doesn't do a thing.

Bill
 
So, to summarize:

The counter weight on the PC is a remnant of it's original function as a sander. Using different backing plates with the same counter weight doesn't seem to affect effectiveness (not enough to notice anyway) so it shouldn't be a big issue.

Setec Astronomy... Too many secrets?
 
Overall speed the PC spins faster(6800opm)than a Flex-Fact, so DLC is right.
Now before the eyebrows are raised by the 3401 guys(I too own one), thinking PC=6800opm vs Flex advertised 9600opm(nooone not even Flex knows where this figure came from), the truth is... Mike Phillips has a thread where he measured the amount of orbits per rotation and they were "11" orbital movements for every rpm/rotation. Now what is accurate is a Flex at maximum speed 6 rotates at 480rpm. 11 orbits x 480rpm=5280opm, very far off the pie in the sky 9600opm.

Simple maths: PC 6800opm - Flex 5280opm = 1520opm advantage the PC has over the Flex.

In Free air spin at speed 6, I can hear and see my DAS6(PC) spin faster than my 3401 at speed 6.

HOWEVER....

Once you put the polisher and pad to the paint, pressure and curves takes its toll on the PC. In a perfect world the PC will outspin a Flex3401, but we live in a world where cars have curves and deeper swirls need more pressure. This is where the 6800opm of the PC starts to slow down atleast 50%. So opm drops from 6800 to roughly 3400opm.

The Flex on the otherhand being forced rotation will maintain 5280opm no matter what the circumstance and thats what has earned the 3401 such cult status, apart from being built like its meant to survive an apocalypse.
 
Nice summary, Zubair!

My experience has been different. Like Kevin stated, factors such as pad type, compound, and technique should also be factored in. I know that when I use stiff cutting pads I lose a ton of rotation on curves and contours. The pads and compounds I use are better able to maintain rotation in those situations. These same pads make handling the 3401 a lot more comfortable to use - for me.

But you have a great lot of info in your post!
 
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