Pad #05575 Back-Up Pad for Random Orbital Sanders
For use in most sanding applications.
Fits all standard (5/16-24 thread) sanders.
A medium density yellow foam pad with a moderately flexible edge - good for flatter surfaces
Appoximate 45 bevel makes for a softer edge, better contact on contoured surfaces, and allows the sanded area to be "featheredged" or more easily blended
Blue vinyl pad face provides good disc adhesion yet allows easy removal
Sold by the each; 10 per case
Heavy on the technical side...
Should you use a soft or firm sanding disc backing pad?
After you have decided between Stikit or Hookit, and chosen no-hole or clean sanding discs, and selected the disc diameter, you will still often be left with the choice of a firm or a soft backing pad.
As a general rule, you should use coarser abrasive discs on firm backing pads, and finer grit discs on soft backing pads.
Soft Backing Pads
Soft pads are not intended for use with very coarse abrasive discs, as the higher stresses induced by very coarse abrasives fatigues the foam prematurely.
Having said that, a soft pad can
be used with coarse grit discs for heavy material removal on rounded surfaces - like a sailboat hull - where it would be difficult to maintain full surface contact with a stiffer, firm backing pad.
Just don't expect the soft pad to last as long.
Firm Backing Pads
Using coarse discs on a firm backing pad works very well, as long as the work surface is flat
Using a firm pad on a curved surface can easily result in hard-to-remove gouges and scratch marks.
If the surface isn't flat - again, like a sailboat hull - you will generally want to use a softer pad for full surface contact, no matter what the grit of the sanding disc.
Firm pads are also recommended for leveling uneven surfaces - such as paint brush strokes and runs.
In this application, a soft pad might simply conform to raised areas, rather than cutting them down.