Choosing Sanding Discs for Festool and Dust-Extraction Sanders
Posted by Kimberly Fontaine-Goodwin on
Why Hole Patterns Matter
Dust-extraction sanders — including Festool, Mirka, Indasa, and many others — use a vacuum system to pull sanding dust through holes in the disc and backup pad, directly into a dust extractor or bag. This keeps the abrasive surface clean, extends disc life dramatically, and virtually eliminates airborne dust.
For this system to work, the holes in the sanding disc must align with the holes in the backup pad. Use a disc with the wrong hole pattern and you'll block the airflow, clog the abrasive, and defeat the purpose of the dust extraction system entirely.
Common Hole Patterns
There is no single universal hole pattern — different manufacturers use different configurations. Here are the most common ones you'll encounter:
- 6-hole: A simple 6-hole pattern used on many standard DA sanders. Common on entry-level and mid-range pneumatic and electric sanders.
- 8-hole: Used on many 5" and 6" random orbital sanders. Widely compatible across brands.
- 9-hole: Common on Festool 5" (125mm) sanders like the ETS 125 series.
- Multi-hole / Ultravent: High-density hole patterns (33-hole, 67-hole, or more) used on premium dust-extraction sanders. More holes = better dust extraction = longer disc life. Indasa's Ultravent and Mirka's multi-hole discs fall into this category.
- Solid (no holes): Used without dust extraction, or with a separate vacuum shroud. Common for PSA discs on older machines.
Festool Disc Compatibility
Festool sanders use metric sizing (125mm = ~5", 150mm = ~6") and specific hole patterns depending on the model:
- Festool ETS 125 / RTS 400: 125mm (5") discs, typically 8-hole or 9-hole pattern.
- Festool ETS EC 150 / RO 150: 150mm (6") discs, typically 6-hole or multi-hole.
- Festool Rotex RO 90: 90mm discs with a specific hole pattern.
Always verify the hole pattern on your specific Festool model before ordering discs. The model number is printed on the sander's label.
Does Brand Matter?
Festool does not require you to use Festool-branded discs. Any disc with the correct diameter and hole pattern will work — and aftermarket discs from brands like Indasa, Mirka, and Sunmight often offer equivalent or better performance at a lower cost per disc.
The key specs to match are: diameter (5" / 125mm or 6" / 150mm), hole pattern, and backing type (hook-and-loop for Festool pads).
Interface Pads for Contoured Surfaces
When sanding curved or contoured surfaces with a random orbital sander, an interface pad — a soft foam layer that sits between the backup pad and the disc — allows the abrasive to conform to the shape of the surface. This prevents the hard edge of the backup pad from leaving circular marks on curved panels.
Interface pads are available in various thicknesses (typically 3mm or 10mm) and must also have matching hole patterns for dust extraction to work through them.
Pad Savers: Protect Your Backup Pad
Backup pads are the most expensive consumable on a dust-extraction sander. A pad saver — a thin foam disc that sits between the backup pad and the sanding disc — protects the hook material from wear and extends pad life significantly. They're inexpensive insurance for a $40–$80 backup pad.