View Full Version : Which DA should I buy and why does my Porter Cable stall.

11-01-2019, 03:46 PM
These 2 questions are actually related.
I am surprised at how easy it is to stall my Porter Cable DA, which is probably 12 years old (but lightly used; I am an enthusiast, not a pro). Even a light touch - say just the weight of the machine, causes it to stall (it just jiggles).
Is it perhaps worn out, or is lots of stalling typical? I try to use proper techniques but it might be operator error.
To the other question - maybe upgrading to a Griot G9, or a Flex/Rupes pro machine is worth considering.
I donít mind paying for the Flex or Rupes if they are worth it, but for only a couple of uses/year, I wouldnít mind saving the difference in cost.
If I do upgrade (hoping to reduce stalls), would like suggestions as to which machine.
BTW, I have been using CarPro products for about a year and canít say enough good things about them and this forum. Thanks for both.

The Guz
11-01-2019, 05:04 PM
Which porter cable do you own? DA's can stall if not held correctly.

Forced rotation machines will not stall. Flex and Rupes make one.

The Rupes DA's will still stall and it does take a little bit of a learning curve with it. You have options from Griots with the G9 and their long throws. The G9 looks like it can still be stalled but it has more power than the Porter Cable.

11-01-2019, 08:27 PM
The Porter Cable is a 7424.
Maybe I need to work on my technique.
Can you suggest an instructional video?

The Guz
11-02-2019, 01:47 AM
Mike Phillips is always a good person to lean from.



11-02-2019, 06:09 PM
Is is a 7424 or a 7424xp Dual Action (DA) machine?

IMHO There are a couple of way to go and continue to use your existing DA machine.

1) 5" backing plate - IMHO a 5" backing plate makes a big difference on a DA machine
I like the Meguiar'sģ 5" Soft Buff DA Backing Plate, DBP5

2) Meguiars DA Foam Discs are ultra-thin foam pads DFC5, DFP5, & DFF5
Thin 5" pads IMHO work better on a 5" backing plate on a Porter Cable machine.

3) Keep the machine level. A PC/DA is designed to "stall" when it is not on a flat surface.
This is called "a free-floating spindle assembly" (it is not a clutch)
The is so you do not burn through areas, high ridges, etc. like you can with a direct drive.

Now if you are ready to upgrade to a newer modern technology I'd suggest...Rupes Polisher 21 (https://www.carpro-us.com/search.php?search_query_adv=rupes%2021%20bigfoot&section=product)
This is by far my favorite tool for detailing! The Rupes 21 has an orbit of 21MM (which is HUGE).
The orbit allows the polisher to cut paint efficiently and without installing swirls. Itís a must-have!
Again, for me, I prefer the control of a 5" backing plate and changed the Rupes 21 to a 5" backing plate

Here is a videos on different machine technology.


11-03-2019, 12:58 PM
Here's another machine comparison video.
Although a little older vid...I thought was still very informative.


11-03-2019, 06:13 PM
Thanks again for all the help. I watched Mikeís video and realized I was not using a high enough speed and that I would occasionally have the pad on edge.
A big help - glad we have you helping us out!

01-08-2020, 12:32 PM
What pads/compounds are you using?

BTW - My favorite all-around machine is the Rupes 21 with a 5" backing plate and 5" pads.