4" x 24″ Cork Sanding Belt – 6 Pack | For Premium Glass Fabrication Finishing

When the glass cannot come to the wet belt sander, the polishing has to happen on a portable machine. A Makita 9403 or 9404 class 4 x 24 belt sander fitted with this ungritted cork belt and charged with cerium oxide slurry polishes an installed table top edge, a storefront lite or a countertop return to clear, on site, after the same sander has taken the edge to 400 to 800 grit with a silicon carbide belt.

We convert these belts in Anaheim, California from natural cork bonded to a cloth backing, six to a pack. Glass installers, stone fabricators finishing seams and returns in place, and shops with a 4 x 24 sander clamped in a bench stand as their only edging machine are the buyers. The four inch face suits big flat edges and bevels; for cutouts use the 1-1/8 x 21 cork belt.

• Ungritted natural cork on cloth: a polishing carrier for cerium oxide or pumice, not an abrasive
• 4 x 24 size for the Makita 9403 and 9404, Milwaukee 4 x 24 and Ridgid EB4424
• Polishes on site: installed glass, countertop edges and returns, large lites
• Follows the 4 x 24 silicon carbide belt on the same sander after 400–800 grit
• Runs damp with slurry, so no water feed is needed on a portable sander
• Six belts per pack; converted in Anaheim, California

What does a cork belt do on a portable sander?

A 4 x 24 silicon carbide belt seams, shapes and refines a glass or stone edge, but even at 800 grit it leaves a fine grey matte. Cork has no grit. The ungritted cork face soaks up polishing compound and presses it against the edge with enough firmness to remove that last matte, which is why every glass shop's final belt is cork rather than a finer abrasive.

On a portable sander the arrangement has a practical advantage. The silicon carbide stages want water or, failing that, extraction and a respirator; the cork stage wants only a damp belt and slurry, which is easy to manage on a job site with a squeeze bottle. Charged with cerium oxide the belt gives a clear optical polish on glass; charged with pumice it gives a quicker bright pre-polish. With a fine polishing paste it finishes granite, quartz, solid surface and acrylic; with a green stainless compound knife makers use cork after 600 to 800 grit for a satin to mirror pre-polish.

Which compound should you carry with a 4 x 24 cork belt?

• Cerium oxide: for exposed, polished edges on table tops, shelves, shower doors and mirrors. Mix with water to a thin cream in a squeeze bottle. Fastest after 600 or 800 grit.
• Pumice: for a bright pre-polish after 400 grit on edges that will be framed, channelled or covered, or as the first of two cork stages before cerium.
• Fine polishing paste: for stone, quartz and solid-surface returns and seams finished in place, and for acrylic.
• Green stainless compound: for steel and knife bevel pre-polish on a 4 x 24 sander in a bench stand.

Compound is sold separately. Mark each belt for its compound and never move a pumice belt onto cerium work; one stray pumice grain will scratch every edge the cerium belt touches afterwards.

Grit guide: the silicon carbide sequence before cork

Cork removes only the scratch pattern left by the last belt. On a portable sander the whole sequence runs on the same machine, so the belt changes are quick and there is no excuse for skipping a grit.

A polished edge that still shows lines when held to the light was not finished properly at the previous grit. Go back one belt and repeat rather than spending more time on cork.

Which machines take a 4 x 24 cork belt?

• Makita 9403 and 9404 4 x 24 belt sanders, the portable machines most glass and stone fabricators use for this size. Verified fit.
• Milwaukee corded 4 x 24 belt sander. Verified fit.
• Ridgid EB4424 oscillating edge belt and spindle sander: a bench machine that takes the same belt, useful for polishing small parts, stone samples and plastics with the belt held vertical.
• Other 4 x 24 sanders, portable or bench-mounted. Confirm the length in the manual; a 4 x 36 bench sander will not tension this belt.

This is the polishing partner to our 4 x 24 silicon carbide glass belt. Mount it the same way: release the tension lever, slide the belt on, check the inside of the belt for a direction arrow, re-tension, start the sander clear of the work and set tracking so the belt runs centred on the front roller. Cork is thicker than a coated belt and tracks a little differently, so re-check tracking after the first minute.

How to charge and run a cork belt on a portable sander

1. Finish the silicon carbide sequence to 400 grit at minimum, 600 or 800 for the fastest cerium polish. Rinse or wipe the edge clean so no swarf reaches the cork.
2. Mix the slurry in a squeeze bottle: cerium oxide or pumice and water to a thin cream.
3. Charge the running belt with the sander held clear of the work, at the lowest speed the machine offers. Squeeze slurry onto the moving cork until the whole face is damp and evenly coated.
4. Present the sander lightly. Start it before it touches the edge, keep it moving along the edge with the platen flat, and let the weight of the machine do the work. Pressure heats glass and does nothing to speed the polish.
5. Keep the cork damp, not wet. There is no water feed on a portable sander and none is wanted; a flooded belt loses its compound in seconds. Add a squeeze of slurry as the face dries and the cut slows, and never run the belt dry with caked compound.
6. Inspect against a light. Any grey remaining means one grit back on silicon carbide, then cork again.
7. Between jobs, back off the tension lever and store the belt flat or hanging in the case. Do not fold a cork belt.

Use it for / don't use it for

Use it for

• Polishing installed glass edges on site: table tops, shelves, storefront and shower door lites already hung
• Polishing flat and bevelled edges on thick or oversized lites in the shop with a hand-held sander
• Granite, quartz and solid-surface returns, seams and laminated edges finished in place
• Acrylic and polycarbonate edges after 400 grit
• Small parts and samples on a Ridgid EB4424-type bench edge sander

Don't use it for

• Seaming, shaping or removing chips; the silicon carbide belt does that
• Anything coarser than a 400 grit scratch
• Running dry with no compound, or so wet that the compound washes off
• 4 x 36 or 3 x 24 sanders; the length is not adjustable

Specifications

Frequently asked questions

Related products and guides

• 4" x 24" Silicon Carbide Glass Fabrication Belts, 12 pack (grinding stages before cork)
• All glass fabrication abrasives (silicon carbide belts, cork belts and discs)
• 1-1/8" x 21" Cork File Belts, 20 pack, for cutouts and notches
• 3" x 24" Cork Sanding Belt, 12 pack, for the Makita 9924DB
• Custom belt sizes, including cork, made to order in about 3 days