4" x 64″ Cork Sanding Belt – 6 Pack | For Premium Glass Fabrication Finishing

A bench-mounted wet belt sander such as the CR Laurence BM64B is often the only edging machine in a small glass shop, so it has to grind and polish. This ungritted cork belt is the polishing half of that job: charged with cerium oxide slurry, it takes the fine matte left by a 400 to 800 grit silicon carbide belt on the same 4 x 64 machine to a clear polished edge.

We convert these belts in Anaheim, California from natural cork bonded to a cloth backing, six to a pack. Small glass shops, shower door installers with a shop bench, art glass studios and stone and plastics fabricators running a 4 x 64 bench wet sander are the buyers. On a one-machine shop the discipline is the changeover: rinse the machine, swap to cork, turn the water down, charge and polish.

• Ungritted natural cork on cloth: a polishing carrier for cerium oxide or pumice, not an abrasive
• 4 x 64 size for the CR Laurence BM64B bench wet belt sander and other 4 x 64 machines
• Follows the 4 x 64 silicon carbide belt on the same bench machine after 400–800 grit
• Lets a one-machine shop grind and polish edges on the same bench sander
• Six belts per pack; a charged cork belt lasts many shifts
• Converted in Anaheim, California; free shipping on orders over $200

Why can the BM64B not polish with silicon carbide alone?

The silicon carbide belts on a bench wet sander do the shaping and refining, and the finest of them, 800 grit, still leaves a uniform grey matte because every abrasive grain cuts a scratch. Polishing needs loose compound pressed against the glass by a carrier with no grain of its own. Ungritted cork is that carrier: soft enough to conform to a pencil edge or bevel, firm enough to work the compound, and impossible to scratch with.

Charged with cerium oxide, the cork belt clears the matte and leaves a polished edge. Charged with pumice, it gives a quicker, cheaper bright pre-polish suited to edges that will sit in a channel or frame, or a first stage before cerium. Run dry, or with no compound, it only heats the glass. With a fine polishing paste it finishes granite, quartz, solid surface and acrylic; with a green stainless compound it pre-polishes steel and knife bevels after 600 to 800 grit.

Which compound should you run on a 4 x 64 cork belt?

• Cerium oxide: for exposed polished edges on shower doors, mirrors, shelves and table tops. Mix with water to a thin cream. Fastest after 600 or 800 grit.
• Pumice: for a bright pre-polish after 400 grit where a full optical polish is not required, or as the first cork stage before cerium.
• Fine polishing paste: for stone, quartz, solid surface and acrylic on the same bench machine.
• Green stainless compound: for steel and knife work on a 4 x 64 belt grinder.

Compound is sold separately. Keep one belt per compound and mark the inside. On a single bench machine that also runs silicon carbide, rinse the machine and the tray before the cork belt goes on so no grit is carried into the cork.

Grit guide: the silicon carbide stages before the cork belt

Cork removes only the previous scratch pattern. On a BM64B every stage runs on the one machine, so step through the grits and do not jump from 220 to cork.

If the polished edge shows lines under a light, the previous grit was not finished. Swap back to that silicon carbide belt, complete it, and polish again; more cork time will not remove them.

Which machines take a 4 x 64 cork belt?

• CR Laurence BM64B heavy-duty bench wet abrasive belt sander: the machine this size is converted for. One belt at a time, silicon carbide or cork.
• Other bench or upright wet belt sanders built for a 4 inch by 64 inch belt. Confirm the length in the manual; a 4 x 54 machine will not tension this belt and a 4 x 84 will not take up the slack.
• Bench belt grinders of the same size in stone, solid-surface and plastics shops.

This belt is the polishing partner to our 4 x 64 silicon carbide glass belt and mounts the same way: release tension fully, seat the belt centred on both wheels, check the inside for a direction arrow, re-tension, then jog the machine and set tracking before charging. Cork is thicker than a coated belt, so back the tension off slightly from the silicon carbide setting and re-check tracking after the first piece.

How to change over from grinding to polishing on one bench sander

1. Finish on silicon carbide at 400 grit or finer, 600 or 800 for the fastest cerium polish. Rinse the glass so no swarf travels to the cork.
2. Rinse the machine. Flush the platen, wheels and tray so loose silicon carbide grit is gone before the cork belt goes on.
3. Mount the cork belt, set tracking, and turn the water feed off or down to a bare trickle. Cork runs damp with slurry, not flooded.
4. Mix cerium oxide or pumice with water to a thin cream and charge the running belt at low to moderate speed until the whole face is evenly damp.
5. Polish with light pressure, keeping the glass moving along the belt as you did on silicon carbide. Pressure heats the edge and does not speed the polish.
6. Re-charge as the face dries and the polish slows. Never let the belt run dry with compound caked on it.
7. Check under a light. At the end of the run, back off the tension and hang the cork belt or leave it mounted. Do not fold it.

Use it for / don't use it for

Use it for

• Polishing flat, pencil and bevelled glass edges on a BM64B or similar bench wet sander
• Shower door, mirror, shelf and table top edges in a small shop with one edging machine
• Bright pre-polish with pumice on edges that will be framed
• Granite, quartz, solid-surface and acrylic edges after 400 grit
• Knife and steel pre-polish with green compound on a 4 x 64 grinder

Don't use it for

• Seaming, shaping or chip removal; the silicon carbide belt does that
• Anything coarser than a 400 grit scratch
• Running under full water flow, or running dry without compound
• 4 x 54 or 4 x 84 machines

Specifications

Frequently asked questions

Related products and guides

• 4" x 64" Silicon Carbide Glass Fabrication Belts, 12 pack, for the CRL BM64B
• All glass fabrication abrasives (silicon carbide belts, cork belts and discs)
• 4" x 54" Cork Sanding Belt, 6 pack, for compact bench wet sanders
• 4" x 84" Cork Sanding Belt, 6 pack, for upright wet sanders
• Custom belt sizes, including cork, made to order in about 3 days