6.5" pad on a 5" backing ok? Wool and Microfiber Pads, and Harbor Freight DA

[HandyFrank]

Will a 6.5" pad work on a 5" backing? I'm considering buying the Harbor Freight DA Polisher to buff my boat, and maybe my car 1 time a year. I was planning on upgrading the backing plate to the Astro Pneumatic 5" plate on Amazon. Will this handle 6.5" pads ok?

I'm planning on using the Shurhold Pads (Wool and Microfiber) since I'm using their Buff Magic Compound and Pro Polish. I watched some YouTube Videos and it seems like people like these pads and these products for their boats, so I want to use them but without their buffer, and use the Harbor Freight one instead.

Here are the 3 pads.
6.5" Polish Pad
Amazon.com: Shurhold 3152 6-1/2" Pro Polish Pad, (Pack of 2): Automotive

6.5" Wool Pad
Amazon.com: Shurhold 3151 6-1/2" Buff Magic Compounding Pad, (Pack of 2): Automotive

Microfiber Bonnet/Shag
Amazon.com: Shurhold MICROFIBER BONNETT: Automotive

5" Backing Plate
Amazon.com: Astro Pneumatic 4607 5" PU Velcro Backing Pad: Automotive

Will that 5" plate be ok with these pads? Or should I go with a 6"?

 

[HandyFrank]

Researching a bit more, it seems like most people recommend a 5" backing plate be used with 5.5" pads, and a 6" backing plate be used for 6.5". However, I see lots of people say a 5" backing plate is good for pads from 5" up to 6.5".

Anyone who can share some knowledge will be great, Thanks!

 

[Mike PhillipsMike Phillips is verified member.]

I see lots of people say a 5" backing plate is good for pads from 5" up to 6.5".

Anyone who can share some knowledge will be great, Thanks!

Yes. The key word being "can". The 5" backing plates can be used with 6" and 6.5" pads.

The upside is the pads will tend to "mushroom" around the backing plate, that means they will bend or fold back, away from the surface being buffed and around the backing plate. In most cases with a larger pad there will be ample velcro cloth so the foam (or whatever the pad is made of), won't be damaged by the edge of the backing plate.

This folding over can be a good thing for a newbie as it means there's never a chance of the edge of the backing plate coming into contact with the surface being buffed which can be a risk when using backing plates that are exact fit, that is the backing plate runs out to the very edge of the pad being used. For exact fit backing plates you want to have a tick more experience than an absolute newbie and of course... all of us should always be...

focusing on the task at hand



The downside of backing plate that is smaller than the pad being used is there's no support for any portion of the pad that has not backing plate behind it. This of course means the portion of the pad without backing plate support will be doing little to no work since the pad will simply push away from the surface instead of engage the surface.

With some tools there could be a balance or vibration issue using too large of a pad for too small of a backing plate.

With more mass from the pad but less attachment surface area between the velcro on the back of the pad and the hooks on the backing plate the chances a pad will fly off the backing plate and fly off faster than if using the correct size backing plate increases but in reality you should never hold a tool and pad system in the air with the tool turned on.

I probably missed a few relevant points but it's been a long day and I just sat down at my computer and replied to your thread.


Big picture is you'll be a lot better off in every aspect to use the correct size backing plate for the pad you want to use.

 

[HandyFrank]

Yes. The key word being "can". The 5" backing plates can be used with 6" and 6.5" pads.

Hi Mike,
Wow, talk about a great response and knowledge! Thank you for this. So it seems like I'd be better off going with a 6" backing plate for these 6.5" pads. I may stick with a 5" packing plate for my cars and the 5.5" pads, and try it out with the 6.5" pads on that plate first and let the results/experience dictate if I need 2 backing plates.

I've forever wanted to be able to remove my own swirl marks from a car that has gone through the car wash too many times. Maybe now i'll get my chance to do it

Thanks!