Porter Cable 7424XP - Question
 

Ok, I got this polisher in the winter and just got to using it this week. Ive read about what im going to ask but prefer the voices of the Z forum over others... when using it, I noticed that it seemed like the pad was not really spinning much, but more "vibrating". Then I started playing with it and realized that it would only really spin when not touching any surface. Ive read its normal and you have to get used to it but just wanted some advice.. maybe im doing it wrong?

You are using too much pressure. I use the same PC. I buy most of my detailing products from Adams Polishes and they have a great forum (www.Adamsforums.com). There is some great info about detailing on there, especially info on the PC.

Best of luck...it just takes practice.

Draw a line on the backing plate. Once you turn on the PC on the paint surface, you should see that line turn. If it doesnt you are using too much pressure. Give that a shot.

:iagree: Use a sharpie to mark a line so you can keep track.

Ok, i will give it a shot. But i dont think im applying too much pressure. when doing, for example, the hood, i can hold it with 1 hand and only have the weight of the polisher doing the work and it still seems to stop... when doing the sides it seems even harder to get it to spin...

Do you have the proper counterweight installed??

Installed? There was nothing in the instructions saying i needed to install anything except for the backing plate...

Its not going to have much rpm to begin with its made to make it easy to use and safe so people dont burn through their paint. Lessen your pressure and it should increase rpm.







DAN

ok, guess ill just have to play with it more. just seems like once any pressure is applied, it barely turns, literally...

Ive read a lot of stuff that says its normal to do this and it will still work...

This:

http://photos-h.ak.fbcdn.net/hphotos..._7469456_n.jpg

Thanks. yes, that piece is on there. I am using a 5 inch backing plate with a 6.5 inch pad... i assume its ok... maybe it needs to be tightened or something...

I also need to mark a line on the backing plate to be sure of how much it is actually spinning...

Using a 6.5" pad is the problem. Switching to a 5" will make a big difference.

Really? Autogeek.net recommended using this setup for beginners. I trust their info usually...

I guess ill buy a few 5 inch pads and play around. If thats the fix, then good!

But I only see 5.5 inch pads. I assume these are what i need?

Yes, 5.5" pads would be good. Check out Detailers Domain.com, email Phil. He is very helpful and also is a the370z.com forum supporter. He'll get you set with what you need.

The counterweights are designed for either 5 or 6 inch pads. There are two different sizes. A 5 inch counterweight will not work well with a 6.5" pad.

Counterweights when using the PC for polishing absolutely do not matter... a 5 or 6" counterweight will work just fine and as far as I'm aware those are the only 2 sizes they come equipped with.

Remember - its a counterWEIGHT not counterSIZE... so the jump from a 5 to a 6 or 6.5" pad does not require a different weight. You're offsetting the weight, and another 1-1.5" of foam doesn't make a significant enough difference in weight to justify a change.

To the OP... what speed are you running the machine at? Anything at setting 4 or below and it takes almost no pressure at all to stop the rotation of the backing plate. We recommend that all polishing be done at setting 5 or 6.

Even at speed 5 you may see the pad stop from time to time due to the contours of the vehicle... remember the PC is not driven to rotate, its simply the centrifugal force of the oscillation that causes it to spin. So when you come up to a contour or curve that is in opposition to that rotation it may stop or slow, just work on keeping your pressure constant.

The only other thing that could be attributed to stopped rotation is lack of speed caused by using an improper gauge extension cord. When this happens you may notice the machine stop or sputter, as well as get excessively hot after short amount of use.

Check out this video specifically when you have a moment... I explain the rotation and pressure using our system. As I get up near the cowl in some of the spots you can see the pad stop rotating for a little bit... its not the end of the world, just practice on keeping that pressure constant.

^ good info!

Great info up above!

I will watch the video when I get a chance. I am new to using the Porter Cable and I only tried to wax the car, not polish, just for practice. I had it at speed setting 3 as I was told it shouldn't go higher for waxing....

Oh, then you're absolutely fine! Waxing with the PC is a totally different animal than polishing. You don't have to worry about pressure, rotation, and all that... you're not breaking the product down or attempting to impart change on the clear coat, you're simply spreading a thin coat of product over the surface.

in this video I'm demoing the Flex 3401 which has forced rotation to it, but it should give you an idea of the time/pressure/etc you'll use to apply wax or sealant to the finish by machine... its not much.

Dylan,

So your saying, that with the Porter Cable not spinning much really at all isnt a problem for waxing? I figured it was still getting the job done as it was spreading the wax and thats really all that matters. Just want to be sure and also that the machine was working properly..

Thanks again for your help and peace of mind...

Yes... the spinning part of the movement and the close attention to how much pressure is all a part of POLISHING. For waxing all you're doing is spreading the product on the surface so there is no need to worry about the rotation.