Does the size of the backplate make a huge difference ?

The smaller the contact or surface area of the pad the more kinetic (heat) energy is transferred to a given paint surface area. A pad should be designed to efficiently use its surface area.



Different pad sizes can have an impact on how the buffer breaks down a polish, as it applies its dynamic friction over less area, control, better manoeuvrability, and how fast you can cover an area.



Smaller pads in general will offer you more control with any machine polisher, as it can reduce the tendency for the buffer to hop or skip on the paint. Smaller pads also make it easier to manoeuvre buffers in tighter areas and closer to trim pieces.



The low profile 5.5 inch buffing pads pack the same CCS technology and performance into a compact, highly effective size that works best with dual action polishers and air sanders. Use with a 5 - inch moulded urethane backing plate for excellent flexibility and balance by Lake Country (LC) manufacturing.



Assuming equal speed, radius and foam compression (50% - 15 pounds of force applied) the difference between 4- inch and 6 - inch pads is their different surface area = π (r2) (4-inch = 12.46 sq.ins / 6-inch = 28.26 sq.ins) and therefore surface kinetic (or dynamic) friction applied and surface pressure applied 4-inch = 3.75 lbs per sq.ins. 6-inch = 2.5 lbs per sq.ins. Even a minor change in pad diameter makes a big difference in surface area.



With the smaller pad you're applying the same force, at a constant speed but over a smaller, more concentrated area, which will induce greater kinetic (friction) and abrasion abilities to the polish, both these abilities require a certain amount of caution as it’s possible to friction burn the paint.

 
Plus, with a smaller pad there's less friction for the machine to struggle against. So you can apply more pressure before the machine merely "jiggles". Not as much of an issue with the more powerful machines like the Griot's, but utterly critical with less powerful units.
 
Accumulator said:
Plus, with a smaller pad there's less friction for the machine to struggle against. So you can apply more pressure before the machine merely "jiggles". Not as much of an issue with the more powerful machines like the Griot's, but utterly critical with less powerful units.



Or those like the Meguiar's that feature a cruise control circuit.



 
Okay because I have a 4 and a 6 inch backing plate and was deciding hich to use. I think after reading this the 4 would be better
 
You asked about backing plate size.



Were you asking in terms of how its size would affect the performance of a pad or disc if the only thing changed was the size of the backing plate?



Or were you asking about changing a backing plate and the size of the buffing pad?



Seems you got recommendations listed on this thread referring to backing plate diameter and also buffing pad diameter.



Big difference!
 
C Charles Hahn- That's a good demo of how well the Meguiar's machine handles the applied pressure!



Kevin Brown- Yeah, I kinda jumped to a conclusion...assuming.... :o
 
It is a bit off topic but if the pad is spinning at about 1 revolution per second under heavy pressure, how much polishing is taking place
 
Lowejackson said:
It is a bit off topic but if the pad is spinning at about 1 revolution per second under heavy pressure, how much polishing is taking place



Probably not much -- that's why under normal circumstances you'd never put that much pressure on a machine; assuming you're referring to the video clip I posted, the only reason I laid most of my weight onto the machine was to demonstrate that even under extremes, it doesn't completely stall. So under most situations when significantly less pressure is applied, it's got plenty of power to get the job done.
 
C. Charles Hahn said:
Probably not much -- that's why under normal circumstances you'd never put that much pressure on a machine; assuming you're referring to the video clip I posted, the only reason I laid most of my weight onto the machine was to demonstrate that even under extremes, it doesn't completely stall. So under most situations when significantly less pressure is applied, it's got plenty of power to get the job done.



Thanks for the response. I should have said I was referring to your video and I should have also said how much I enjoyed watching it
 
4 inch backing plate and 4 inch pad - better cutting power than 3.5 inch plate and 4 inch pad me thinks
 
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