4" x 132″ Cork Sanding Belt – 6 Pack | For Premium Glass Fabrication Finishing

At 132 inches this is the longest cork belt we convert, sized for the CR Laurence BM132RP upright wet abrasive belt sander, the heavy, reinforced machine large glass shops use to seam and edge full-size lites. On that machine the cork belt is the polishing stage: plain ungritted natural cork on a cloth backing, charged with cerium oxide slurry, taking the fine matte left by a 400 to 800 grit silicon carbide belt to a clear polished edge on storefront lites, oversized shower doors and large table tops.

We convert these belts in Anaheim, California, six to a pack. A 132 inch belt carries more compound than any shorter belt and polishes a long edge in one unhurried pass, which is exactly what a shop handling big glass wants from its polishing station.

• Ungritted natural cork on cloth: a polishing carrier for cerium oxide or pumice, not an abrasive
• 4 x 132 size for the CR Laurence BM132RP and other 4 x 132 upright wet belt sanders
• Follows the 4 x 132 silicon carbide seamer belt on the same machine after 400–800 grit
• Longest cork belt in the range: most compound, longest run between re-charges
• Six belts per pack; a charged cork belt stays mounted for many shifts
• Converted in Anaheim, California; free shipping on orders over $200

Why does the BM132RP need a cork belt as well as silicon carbide?

The 4 x 132 silicon carbide seamer belts do the grinding on the BM132RP, from seaming score-break at 50 grit to a fine matte at 800. Every one of those grits cuts scratches, and the finest still reads grey against the polished face of the lite. The clear polish comes from loose compound carried on a face with no grain of its own. Ungritted cork is that face: it holds slurry in its pores, conforms to a flat or pencil edge, and cannot scratch.

Charged with cerium oxide the cork belt removes the matte and leaves the edge clear. Charged with pumice it gives a faster, cheaper bright pre-polish for edges going into a channel or frame, or a first cork stage before cerium. Run dry, or with no compound, it only heats the glass. With a fine polishing paste it finishes stone, quartz, solid surface and acrylic on the same upright; with a green stainless compound it pre-polishes steel after 600 to 800 grit.

Which compound should you run on a 4 x 132 cork belt?

• Cerium oxide: the compound for polished storefront, shower door, table top and mirror edges. Mix with water to a thin cream. Fastest after 600 or 800 grit; workable after 400 with more passes.
• Pumice: for a bright pre-polish after 400 grit on edges that will be hidden, or as the first belt in a two-belt polish before cerium.
• Fine polishing paste: for stone, quartz, solid surface and acrylic on the same machine.
• Green stainless compound: for steel work on a 4 x 132 belt grinder.

Compound is sold separately. On a 132 inch belt a contamination mistake is expensive: one pumice grain carried onto the cerium belt scratches every edge that follows until someone notices. Keep one belt per compound and mark the inside of each belt.

Grit guide: the seamer sequence before the cork belt

Cork removes only the last scratch pattern. On a BM132RP the silicon carbide sequence and the cork stage run on the same machine, or the cork belt lives on a second upright dedicated to polishing.

Haze or lines under a light after polishing mean the previous grit was not completed along the whole edge, which on a full-size lite usually means the ends. Return to the last silicon carbide belt, finish the ends, and polish again.

Which machines take a 4 x 132 cork belt?

• CR Laurence BM132RP upright wet abrasive belt sander: the heavy-duty, reinforced upright that runs one 4 x 132 belt at a time. This is the machine the belt is converted for.
• Other upright or horizontal wet belt sanders built for a 4 inch by 132 inch belt. Confirm the length in the manual; a 4 x 106 machine will not tension this belt.

Mounting matches the silicon carbide belt: release tension fully, seat the belt centred on both drums, check the inside for a direction arrow, re-tension, then jog the machine and set tracking before charging. Handle a 132 inch cork belt by the loop, never by the edge, so the cork is not creased, and back the tension off a little from the silicon carbide setting because cork is thicker. Expect some drift in the first minute as the long loop settles; re-check tracking after the first few lites.

How to charge and run a cork belt on the BM132RP

1. Finish on silicon carbide at 400 grit or finer, 600 or 800 for the fastest cerium polish. Rinse the lite so no grinding swarf is carried to the cork.
2. Turn the water feed off, or down to a bare trickle. Cork runs damp with slurry, not flooded; full flow strips the compound off a long belt before it reaches the glass.
3. Mix the slurry: cerium oxide or pumice and water to a thin cream.
4. Charge the running belt at low to moderate speed with a brush or squeeze bottle. A 132 inch belt takes two or three full revolutions to coat evenly; wait until the whole face is damp before presenting glass.
5. Present the edge lightly and keep the lite moving along the platen at the same steady pace used on the silicon carbide belt. Pressure heats glass and does not speed the polish.
6. Re-charge as the face dries and the polish slows. The long belt goes further between charges than a short one, but never let it run dry with compound caked on it.
7. Check under a light, and at shift end back off the tension and leave the belt mounted or hang it from a wide hook. Do not fold or crease a cork belt.

Use it for / don't use it for

Use it for

• Polishing flat, pencil and bevelled edges on full-size storefront lites, oversized shower doors and large table tops on the BM132RP
• A dedicated polishing upright alongside a silicon carbide seaming machine of the same size
• Bright pre-polish with pumice on large lites going into channel or frame
• Stone, quartz, solid-surface and acrylic edges after 400 grit
• Steel pre-polish with green compound on a 4 x 132 grinder

Don't use it for

• Seaming, shaping or chip removal; the silicon carbide seamer belt does that
• Anything coarser than a 400 grit scratch
• Running under full water flow, or running dry without compound
• 4 x 106 or 4 x 84 machines

Specifications

Frequently asked questions

Related products and guides

• 4" x 132" Silicon Carbide Glass Seamer Belts, 12 pack, for the CRL BM132RP
• All glass fabrication abrasives (silicon carbide belts, cork belts and discs)
• 4" x 106" Cork Sanding Belt, 6 pack, for CRL 2300 and DBS106 machines
• 4" x 84" Cork Sanding Belt, 6 pack, for upright wet sanders
• Custom belt sizes, including cork, made to order in about 3 days