The Mirka Ceramic Supreme Fiber Disc 4 inch is a ceramic fiber disc built for cutting and grinding metal. This is a fiber disc designed for fast material removal on stainless steel and high-tensile alloys. Model Number 63-438-036. If you need a coarse abrasive for hard metals where ordinary discs can slow down, this one is aimed at that kind of work.

What matters here is the combination of ceramic abrasive, a 4 inch disc size, and P36 grit. In plain terms, that means this disc is set up for aggressive work, not fine finishing. It is meant to bite into tough material, help remove stock quickly, and keep productivity up when you are cleaning welds, grinding edges, or prepping steel surfaces for the next step.

Mirka positions this disc for stainless steel and high-tensile alloys, which tells you exactly where it belongs. Those materials can be demanding on abrasives, so product choice matters. A ceramic fiber disc is the kind of abrasive serious metalworkers reach for when they need efficient grinding performance on harder metals instead of a disc that gives up early.

The 4 inch size makes sense when you want a smaller grinding disc that is easier to control in tighter working areas or on smaller parts. That can be useful for fabrication work, repair work, and detailed grinding where a larger disc would feel less precise. The center hole format also makes it part of the standard fiber disc style used with the proper backing pad setup.

This Mirka grinding disc is also listed as suitable for steel and lacquers. That gives it some added versatility for surface prep tasks where material type can change from one step of the job to the next. Just keep the grit in mind: P36 is a coarse option, so it is best used when speed and removal matter more than surface refinement.

Who should buy it? Metal fabricators, welders, maintenance techs, and serious DIY users who already know they need a coarse 4 inch fiber disc for grinding and cutting tasks. If your work involves stainless, tougher alloys, or fast cleanup on steel, this is the right kind of abrasive. If you are chasing a finer finish, you will want a finer grit than this one.

Mirka Ceramic Supreme Fiber Disc 4 inch means business

This is the kind of disc you buy when the job is removing metal fast, especially on tougher materials that can punish a weaker abrasive.

• Who it's for: Welders, fabricators, maintenance crews, and serious DIY users doing real grinding work on steel, stainless, and hard alloys.
• Why it stands out: Ceramic grain, coarse P36 grit, and a practical 4 inch format make it a solid choice for aggressive cutting and grinding.
• Worth knowing: This is not a finishing disc. It is a 25-pack of coarse fiber discs, so plan on a finer follow-up step if surface finish matters.

• What material is this disc designed to handle? It is designed for cutting and grinding stainless steel and high-tensile alloys, and it is also listed as suitable for steel and lacquers.
• Is this a finishing disc? No. The P36 grit is a coarse grit intended for aggressive material removal and surface prep rather than fine finishing.
• What size is the disc? The disc diameter is 4 inches.
• How many discs come in a pack? This part number is sold as a 25-piece pack.