4" x 84″ Cork Sanding Belt – 6 Pack | For Premium Glass Fabrication Finishing

Production glass shops that run a floor-standing upright wet belt sander with a 4 x 84 belt usually keep a second one, or a scheduled changeover, for polishing. This is the belt that goes on it: plain ungritted natural cork on a cloth backing, charged with cerium oxide slurry, taking the 400 to 800 grit matte left by the silicon carbide belt to a clear polished edge on shower doors, table tops, shelves and storefront lites stood against the tall platen.

We convert these belts in Anaheim, California and pack them six to a box. An 84 inch cork belt carries a lot of compound and polishes a long edge in one steady pass, which is why shops finishing large lites prefer it to a short belt on a bench machine. Stone, solid-surface and plastics shops with the same class of upright buy them too.

• Ungritted natural cork on cloth: a polishing carrier for cerium oxide or pumice, not an abrasive
• 4 x 84 size for upright and horizontal wet belt sanders built for that belt
• Follows the 4 x 84 silicon carbide belt in the same size after 400–800 grit
• Long belt holds more slurry and polishes long edges in one pass
• Six belts per pack; a charged cork belt stays mounted for many shifts
• Converted in Anaheim, California; free shipping on orders over $200

Silicon carbide grinds, cork polishes: why a shop needs both 4 x 84 belts

Both belts are sold in the 4 x 84 size and they are not interchangeable. The 4 x 84 silicon carbide belt seams, shapes, bevels and refines the edge through the grits to a fine matte. This ungritted cork belt has no grain at all; it holds loose polishing compound in its pores and rubs it against the glass with enough firmness to remove that last matte and leave the edge clear.

Charged with cerium oxide slurry the cork belt gives the clear optical polish that exposed edges need. Charged with pumice it gives a quicker, cheaper bright pre-polish for edges that will be framed or channelled, or a first cork stage before cerium. Run dry, or run with no compound, it only heats the glass. Charged with a fine polishing paste it finishes granite, quartz, solid surface and acrylic; charged 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 84 cork belt?

• Cerium oxide: for polished shower door, table top, shelf 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 cork belt in a two-belt polish before cerium.
• Fine polishing paste: for stone, quartz, solid surface and acrylic on the same upright.
• Green stainless compound: for steel and knife work on a 4 x 84 belt grinder.

Compound is sold separately. Dedicate each belt, and ideally each machine, to one compound. A pumice grain carried onto a cerium belt will scratch every edge polished after it, and on an 84 inch belt that is a lot of edges before anyone notices.

Grit guide: the silicon carbide sequence before the cork belt

Cork removes the last scratch pattern only. On an upright the sequence runs on one machine with belt changes, or across two machines with the cork belt permanently on the second.

A polished edge that shows haze or lines under a light was not finished at the previous grit. Return the lite to the last silicon carbide belt, then polish again; more cork time will not fix it.

Which machines take a 4 x 84 cork belt?

• Upright (vertical) wet belt sanders for glass, the floor-standing machines with a tall platen, water feed and a slotted table or rest for large lites, built for a 4 inch by 84 inch belt.
• Horizontal wet belt sanders and long-bed edging machines of the same size.
• Stone, solid-surface and plastics belt grinders built for a 4 x 84 belt.

We do not list a specific model for this length; confirm the size in the machine manual or measure an old belt along its inside, and note that 4 x 54, 4 x 64 and 4 x 106 machines look alike from across the shop. Mounting is the same as the silicon carbide belt: 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 a little from the silicon carbide setting, and expect some drift as an 84 inch belt settles in the first minute.

How to charge and run a cork belt on an upright wet sander

1. Finish on silicon carbide to 400 grit at minimum, 600 or 800 for the fastest cerium polish. Rinse the lite so no grinding swarf reaches the cork.
2. Turn the water feed off, or down to a bare trickle. A cork belt runs damp with slurry, not flooded; full water flow washes the compound off an 84 inch 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. Apply slurry with a brush or squeeze bottle to the moving cork until the whole face is evenly damp; on a long belt this takes a full revolution or two.
5. Present the edge lightly and keep the lite moving along the platen, the same motion 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. Never let the belt run dry with compound caked on it; a caked cork belt glazes and heats the edge.
7. Check under a light, and at shift end back off the tension and leave the belt on the machine or hang it. Do not fold a cork belt.

Use it for / don't use it for

Use it for

• Polishing flat, pencil and bevelled edges on shower doors, table tops, shelves, mirrors and storefront lites on an upright
• Polishing long straight edges in one pass where a short belt would need several
• A dedicated polishing machine next to a silicon carbide edging machine of the same size
• Granite, quartz, solid-surface and acrylic edges after 400 grit
• Knife and steel pre-polish with green compound on a 4 x 84 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, 4 x 64 or 4 x 106 machines

Specifications

Frequently asked questions

Related products and guides

• 4" x 84" Silicon Carbide Glass Fabrication Belts, 9 pack (grinding stages before cork)
• All glass fabrication abrasives (silicon carbide belts, cork belts and discs)
• 4" x 106" Cork Sanding Belt, 6 pack, for CRL-type wet belt sanders
• 3" x 84" Cork Sanding Belt, 8 pack, for 3 inch wet belt sanders
• Custom belt sizes, including cork, made to order in about 3 days