3M 23813 Two-Sided Sanding Sponges, 4.8 x 3.8 in, Assorted, 20-Pack

For collision-repair work involving paint preparation, primer sanding, paint removal, or scratch repair, the 3M 23813 is a hand-sanding sponge with an abrasive surface on each side.

Its soft, low-density foam adds flexibility, while the waterproof bonding system allows wet or dry sanding. That gives it a different role from a rigid sanding block when you want a flexible hand-sanding pad.

The package contains 20 assorted sponges. The listing does not identify the specific abrasive grades included, so the assortment may be harder to match to a job that calls for a named grade.

Specifications

• Name: 3M Two-Sided Sanding Sponge 23813
• Type: Hand sanding sponge
• Format: Two-sided abrasive
• Size: 4.8 in x 3.8 in
• Color: Assorted, grades are color-coded
• What’s included: 20 sponges
• Sanding method: Wet or dry
• Foam: Low-density and soft

Tips for day-to-day use

The product is described for use on multiple surfaces, but the listing does not name specific materials. Match the sponge’s grade to the task before starting, the available details say the grades are color-coded but do not specify which grades come in this assorted set. If a repair calls for a particular abrasive grade, that information matters more than the pack count, so check the grade details for the set before relying on it for that job.

For wet sanding, the waterproof bonding system is a relevant feature. The same sponge can also be used dry, which offers a choice of sanding method without changing to a different product format. The two abrasive sides provide working surfaces on both faces, while the flexible foam makes this a less rigid approach than using a hard sanding block.

Everyday use

A practical use case is hand-sanding a panel during paint preparation, then using the sponge for primer sanding as the repair progresses. It is also listed for paint removal and car scratch repair, though the product details do not specify a particular repair process or promise a finished result. The flexible foam can be useful when a soft-backed hand pad suits the task better than a rigid tool, for work that depends on precise grade selection, the unspecified assortment is a key detail to resolve.

The 20-piece quantity may suit a repair setting where multiple sponges are needed across jobs. For occasional use, the key buying question is less about the count and more about whether the assorted grades fit the work at hand. Worth considering if wet-or-dry hand sanding and a two-sided format are priorities. It’s not for you if the job requires a specific abrasive grade that the set’s listing does not identify.

Practical questions

Can it be used wet and dry? Yes. The description says its waterproof bonding system supports both wet and dry sanding.

Are both sides abrasive? Yes. The sponge is described as having two abrasive sides bonded to soft foam.

Which abrasive grades are included? The set is listed as assorted, with grades available in color-coded versions, but the specific grades in this package are not stated.

Should you buy it?

Choose the 3M 23813 if you need a flexible, two-sided hand-sanding sponge for paint-related work and want the option of wet or dry sanding. The assortment of 20 is useful when several sponges are needed, but it is not a substitute for knowing the exact grade required. If your repair depends on a specific grit, confirm that the set includes it before choosing this assorted pack.