I think we are suffering from a difference in our terminology here. I'd certianly use the terms 'flattening' and 'smoothing' in a different context to the one Dickybee007 seems to be using them for (I'd use 'flattening' to describe getting the surface level on a larger scale with no dips or humps, and 'smoothing' to refer to the state of the surface and getting that as smooth feeling as possible).
All the 3M Scotch-Brite pads are abrasives. There is quite a range of them and you really need to go by the 3M number reference, as some of the colours are duplicated (or very similar looking).
In order of fineness and using the 3M colour description we have:
The coarser the steel wool equivalent (0000 being the finest and grade 4 being the coarsest), the more aggressive the pad will be and the more material it will take off (and the deeper the scratches left behind).
The 5-number pads are slightly smaller (4.5" x 9") than the 4-number pads (6" x 9") so I don't know if there are any real differences apart from that in the actual coarseness, but that's how 3M grade them in their literature.
They all have their uses on different materials, and you'd only want to use the finer grade equivalents on a guitar finish, whereas the coarser grades will be a lot quicker at removing rust from metal etc. 3M themselves describe the white 7445 as 'very mild abrasive for gentle, yet thorough cleaning' and as a light duty cleansing pad.
All the 3M pads are too flexible for what I'd call 'flattening' for flat surfaces, where I'd use sandpaper stuck to a flat board. I'd only use the 3M pads on an already level flat surface, or on curved surface with no obvious dips and humps on.
Reply With Quote
