Proven Quality
Sanding Pad Hardness: Read the Scale Before Comparing
“Soft,” “medium” and “hard” can help you choose within one manufacturer's sanding-pad range. They are much less useful when comparing unrelated pads. A Shore number needs its scale, and a complete pad needs more than a hardness number to describe how it supports an abrasive.
Before replacing a pad that worked well, record its part number. Matching that known assembly is usually more dependable than buying another pad advertised with a similar adjective.
Read the letter beside the number
Shore hardness measures resistance to indentation. Different scales use different measurement arrangements for different materials. Smooth-On's hardness explanation distinguishes the very soft materials measured on Shore 00, flexible rubbers measured on Shore A and harder materials measured on Shore D.
A listing that says only “50 durometer” is incomplete. Ask which scale it means. A 50 on one scale cannot simply be ranked above a 40 on another. Even a conversion chart describes material hardness; it does not predict the sanding result of a multilayer accessory.
Do not assign a number by squeezing a pad with your fingers. That can reveal an obvious difference in feel, but it is not a standardized hardness measurement.
Compare the assembly you will actually use
A machine backing pad, a thin protection pad and a foam interface are different parts. The backing pad mounts to the tool; the other layers, where approved, sit between it and the abrasive. Compare like components before comparing their firmness.
Festool's hard-pad specification, for example, identifies flat surfaces and narrow edges as its applications. That description is more useful than trying to translate every pad into one universal hardness chart. Compare the intended work listed for each approved accessory.
Write the following beside each candidate:
- Specification
- Compatible machine and mounting
- Why it belongs in the comparison
- Determines whether the accessory can be installed correctly
- Specification
- Pad role and part number
- Why it belongs in the comparison
- Distinguishes the backing pad from a protector or interface
- Specification
- Stated hardness and scale
- Why it belongs in the comparison
- Allows a meaningful material-hardness comparison where supplied
- Specification
- Thickness and construction
- Why it belongs in the comparison
- Identifies differences hidden by the same “soft” label
- Specification
- Abrasive attachment and extraction pattern
- Why it belongs in the comparison
- Determines which consumables and dust passages work with it
A thick compliant layer can change how readily the abrasive follows a contour even when the underlying pad is unchanged. Treat adding or removing that layer as a setup change, not a free way to reproduce another pad's specification.
Keep the abrasive constant while judging support
For two approved assemblies, compare their behavior on representative scrap using the same abrasive product and grade. Inspect the intended plane or contour as well as the scratches. A surface can feel uniformly smooth while an edge has become rounder.
For a compatible 5-inch, eight-hole hook-and-loop system, eQualle's 50-pack of assorted sanding discs supplies 80, 120, 180, 220 and 320 grit. Select the grade already appropriate to the trial and keep it fixed when changing pads. The pack contains abrasives, not a replacement backing pad or a hardness standard.
If the manufacturer's specification lacks a Shore value, use its approved application and part number. You do not need to invent a number to make a sound choice.
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