PC7424, Difference in using a 5'' backing plate versus a 6''

ActionPack · 04-26-06, 07:28

I have been using a 6'' B&D random orbit polisher to do most out my buffing for the last 3 years. However as my skills are getting better (i still have alot to learn and thanks to all for the great info they share on this site) i definetly outgrew this buffer. Its not strong enough to remove deep swirls and buff scratches deeper than surface and most important its only 1 speed . The PC7424 is to me the next step prior to a rotary which at this point i think i would do more harm than good with.

Here is my dilemma, there are 2 kits which i am looking right now:
1. The PC7424 (Porter Cable Swirl Buster kit) kit from Eshine.ca with a 5'' backing plate and 3 6.5'' pads.
or
2. PC7424 (Sonus SFX Polisher Kit) kit from Autopia-Car care which comes with a 6'' backing plate with 3 6'' pads.

What is the difference in using a 6'' backplate versus a 5'' one? Will the 5'' allow more flexing of the pads? Are bigger pads better than smaller ones? and if i want to use the MF polishing bonnets i have used on my B&D will they fit on the 6'' backing plate?

Please help

RCBuddha · 04-26-06, 07:32

http://meguiarsonline.com/forums/sho...=backing+plate

I'm sure someone else can chime in on the difference in pad sizes.

ActionPack · 04-26-06, 07:43

Thanks, RCBuddha. The meguiar thread talks alot about effects or non-effects of the counterwieghts. For the same counterwight does it make a huge difference using a smaller or bigger backing plate?

RCBuddha · 04-26-06, 07:57

Quote:

Originally Posted by ActionPack

Thanks, RCBuddha. The meguiar thread talks alot about effects or non-effects of the counterwieghts. For the same counterwight does it make a huge difference using a smaller or bigger backing plate?

Good question, and one that I cannot offer conclusive experience on (though I have experimented a little bit). In theory, if you were to use a 6" backing plate on a 6.5" pad, you should be able to apply more pressure to the pad, then say a 5" plate on the same pad. Again, in theory, being able to apply pressure over a wider area *should* make for better defect removal. Does that make sense?

I hate to talk in hypotheticals, so maybe someone else can chime in with hands-on experience.

eShine · 04-27-06, 04:36

I have used both the 6" backing plate and the 5". I find the 5" allows better flex of the pad edge allowing the pad to flex more in curved areas. I also experienced higher vibrations on speed 6 using the larger/heavier 6" backing plate.

roadwarriorUK · 04-27-06, 10:11

Accumulator · 04-27-06, 01:25

The potential problem with the smaller backing plate is that when pressure is applied it can cut into the back of the pad, usually referred to as a "cookie cutter" type of effect. I've never had any other problems from using a smaller plate with a bigger pad, no uneven polishing or anything like that.

I've used both size plates and never had any big issues either way.

While some don't notice any difference between the two counterweights, I find the best combo to be the biggest weight with the lightest plate/pad combo.

For 6-6.5" pads I prefer the "flex" backing plate which is IIRC a bit smaller than 6". For major correction I use the small backing plate (3.75" IIRC) with 4" pads. With *any* plate/pad I use the 6" counterweight.

Backing plates and counterweights are inexpensive and easily changed. Not a biggie which ones you start out with, I've used a scad of different ones over the years and if you experiment you'll find the combo you like best.

eShine · 04-27-06, 02:33

Quote:

Originally Posted by Accumulator

The potential problem with the smaller backing plate is that when pressure is applied it can cut into the back of the pad, usually referred to as a "cookie cutter" type of effect. I've never had any other problems from using a smaller plate with a bigger pad, no uneven polishing or anything like that.

I've used both size plates and never had any big issues either way.

While some don't notice any difference between the two counterweights, I find the best combo to be the biggest weight with the lightest plate/pad combo.

For 6-6.5" pads I prefer the "flex" backing plate which is IIRC a bit smaller than 6". For major correction I use the small backing plate (3.75" IIRC) with 4" pads. With *any* plate/pad I use the 6" counterweight.

Backing plates and counterweights are inexpensive and easily changed. Not a biggie which ones you start out with, I've used a scad of different ones over the years and if you experiment you'll find the combo you like best.

This was especially true when the pad designs were only using 5" of velcro. The revised design makes it very tough to cut through the velcro. It was very frustrating before the design change, we had many returns!

ActionPack · 04-27-06, 02:44

Thanks all for the info. Its really appreciated.