In the last couple of blogs, we have been talking about the differences between Hook and Loop (H&L) and Self Adhesive (PSA) sanding discs. One of the important differences was how H&L has some flexibility between the mounting pad and the disc face that is not found with PSA mounting pads. This mounting zone is known as the “interface”, and we have discussed why a stiff interface may be desired. But what about having an interface that is even softer than the H&L? Fortunately, soft interface pads are available for many applications.
For those working to finish curved surfaces, this is exactly what they want. From preparing the flowing fender of a classic car to sanding curves on the lathe, a soft interface is the right choice. Stiffer interfaces cannot conform to curves. They have a very small contact area when on a convex surface, and the edge can dig into a concave face, cutting too deep and leaving unwanted scratches. A soft interface pad mounted to the sander allows the disc to conform to the shape being worked, for more efficient material removal and a better quality finish.
Interfaces are available in many sizes from 1-1/4” for touch up sanders to 6” diameter for random orbit sanders. They can be had with dust collection holes or without them, and come in a variety of thicknesses. Thicker pads can be used on tighter radii while thinner pads allow for some flex without losing too much pressure on more shallow curves. Many of these pads are even suitable for wet sanding.
The self adhesive on PSA discs acts much like a lamination that will naturally stiffen both the disc and the mounting surface, so soft interface pads are largely designed for use with H&L sanding discs. We have found that Abranet discs work especially well with soft interface pads because their mesh design is very flexible and helps prevent sanding debris being trapped on the surface. So when your project requires preparing and finishing curves and contours, you can choose the right soft interface pad to get the best results as efficiently as possible.