Mirka Iridium 8-in. 40 Grit Grip Sanding Disc, 133 Holes (24-8MH-040)

Mirka IRIDIUM 8″ Grip, 133 Holes is an 8 inch grip-backed abrasive sanding disc in a 40 grit configuration for fast material removal. This is a sanding disc designed for coarse sanding, stripping, shaping, and surface preparation across wood, metal, fillers, coatings, and composites. Model Number: 24-8MH-040.

The big story here is the cut rate. A 40 grit disc is not for light finish sanding. It is for the early part of the job when you need to remove old paint, break through coatings, flatten body filler, or level rough material before stepping into finer grits. If you’re working on paint removal, aggressive prep, or heavy defect correction, this grit makes sense because it removes stock fast and gives you a strong starting point for the next sanding stages.

The 8 inch size matters on larger work. Bigger discs cover more area with each pass, which helps when you’re sanding broad panels, tabletops, composite surfaces, or other wide sections where a smaller disc would slow you down. For shops and contractors who do repetitive prep work, that larger footprint can save real time over the course of a day.

The 133-hole pattern is there for a reason. Multi-hole disc designs are used to support dust extraction across more of the pad surface instead of concentrating airflow in only a few spots. In practical use, that helps reduce buildup on the abrasive and keeps the disc cutting more consistently, especially on sanding tasks that create a lot of fine dust like filler, primer, paint, hardwood, MDF, and composite materials.

Mirka uses a grip backing on this disc, so swaps are quick when the grit sequence changes or when a worn disc needs to come off. That is a real benefit in production sanding and repair work where you move from coarse shaping into intermediate and finish prep in steps. A secure grip-backed disc also helps keep setup simple for users already running compatible hook-and-loop style backing pads.

Material range is broad, which makes this disc useful in mixed-work environments. Based on the available product data, it is suited for steel, mild steel, stainless steel, copper alloys, non-ferrous metal, plaster, filler, fiberglass, synthetic materials, chipboard, solid surface, composites, veneer, plastics, primer, paint, hardwood, softwood, lacquers, MDF, HDF, and polystyrene. That kind of range is exactly why abrasives like this end up in body shops, cabinet shops, fabrication spaces, and general refinishing work.

If you’re choosing this product, you’re likely buying for one of two reasons: you need a coarse disc that removes material fast, or you need an 8 inch multi-hole abrasive that matches a dust-managed sanding setup. Either way, this is a practical choice for pros and serious DIY users who understand grit progression and want to start the job with an aggressive cut before moving to finer discs for refinement.

Mirka IRIDIUM 8″ Grip, 133 Holes Is Built for the Dirty Part of the Job

If you need a disc that starts the work fast instead of babying the surface, this is the one you grab first.

• Who it’s for: Pros and serious DIY users doing paint removal, filler shaping, composite prep, wood sanding, or metal surface prep on larger areas.
• Why it stands out: You get an aggressive 40 grit cut, an 8 inch format for better coverage, and a 133-hole grip design that fits dust-managed sanding workflows.
• Worth knowing: This is a coarse abrasive, so it is not your finish-stage disc. Plan on following it with finer grits if surface quality matters.

• What type of product is this? This is an abrasive sanding disc with grip backing for sanding and surface preparation.
• What grit is this version? This specific version is 40 grit, which is intended for aggressive stock removal and early-stage sanding.
• What size backing pad does it fit? It is designed for 8 inch sanding setups.
• What materials can it be used on? Based on the available product data, it can be used on wood, paint, primer, filler, steel, stainless steel, non-ferrous metals, plastics, composites, veneer, MDF, HDF, and similar surface-prep materials.