3" x 84″ Cork Sanding Belt – 8 Pack | For Premium Glass Fabrication Finishing

Long, narrow wet belt sanders built for a 3 x 84 belt run a three inch face around a vertical or horizontal platen, and glass shops use them for seaming and flat edging where a four inch belt is wider than the work needs. This ungritted cork belt is the polishing stage for that machine: charged with cerium oxide slurry, it takes the fine matte left by a 400 to 800 grit silicon carbide belt to a clear polished edge on shelves, mirrors, cabinet glass and shower door stiles.

We convert these belts in Anaheim, California from natural cork bonded to a cloth backing and pack them eight to a box. The narrower face suits pencil edges and thinner lites, and an 84 inch loop carries enough compound for long runs between re-charges. Stone, solid-surface and plastics shops with the same class of long-bed sander buy them as well.

• Ungritted natural cork on cloth: a polishing carrier for cerium oxide or pumice, not an abrasive
• 3 x 84 size for vertical and horizontal wet belt sanders and long-bed sanders built for that belt
• Follows the 3 x 84 silicon carbide belt on the same machine after 400–800 grit
• Three inch face suits pencil edges, thin lites and narrow flat edges
• Eight belts per pack; a charged cork belt stays mounted for many shifts
• Converted in Anaheim, California; free shipping on orders over $200

When do you switch from the silicon carbide belt to cork?

When the edge is at 400 grit or finer and looks like an even grey matte with no lines in it. Up to that point the 3 x 84 silicon carbide belt does the work, seaming, shaping and refining under water. From that point on, more silicon carbide only makes a finer matte; the clear polish needs loose compound carried on a face with no grain, and ungritted cork is that face.

Charged with cerium oxide the cork belt removes the matte and leaves the edge clear. 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 with no compound, it only heats the glass. With a fine polishing paste it finishes stone, quartz, solid surface and acrylic on the same machine; with a green stainless compound it pre-polishes steel and knife bevels after 600 to 800 grit.

Which compound should you run on a 3 x 84 cork belt?

• Cerium oxide: for polished shelf, mirror, cabinet glass and shower door 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 of a two-belt polish before cerium.
• Fine polishing paste: for stone, quartz, solid surface and acrylic on the same long-bed sander.
• Green stainless compound: for steel and knife work on a 3 x 84 belt grinder.

Compound is sold separately. Keep one belt per compound and mark the inside; eight belts per pack leaves room for a cerium belt, a pumice belt, a stone belt and spares. A pumice grain in a cerium belt scratches every edge polished after it.

Grit guide: the silicon carbide sequence before the cork belt

Cork removes only the last scratch pattern. On a 3 x 84 machine the sequence runs on one sander with belt changes, or with the cork belt kept on a second machine of the same size.

On a three inch belt it is easy to let a pencil edge roll past the belt edge and miss a strip at 400 grit; that strip shows as a grey line after polishing. Go back one grit, cover the whole profile, and polish again.

Which machines take a 3 x 84 cork belt?

• Vertical wet belt sanders used for seaming and flat edging in glass shops, where the operator holds the lite against a vertical platen with water running down the belt.
• Horizontal wet belt sanders and edging benches built for a 3 inch wide, 84 inch long belt.
• Long-bed belt sanders in stone, solid-surface and plastics shops of the same size.

We do not list a specific model for this size; confirm the belt length in the machine manual or measure an old belt along its inside. If the manual says 84 inches with a 3 inch width, this belt fits; a 4 x 84 machine needs the 4 inch version. 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 ease the tension off a little from the silicon carbide setting. A narrow, long belt shows tracking drift sooner than a wide one, so re-check after the first few pieces.

How to charge and run a cork belt on a 3 x 84 wet sander

1. Finish on silicon carbide at 400 grit or finer, 600 or 800 for the fastest cerium polish. Rinse the glass so no grinding swarf reaches the cork.
2. Turn the water feed off, or down to a bare trickle. Cork runs damp with slurry, not flooded; running water strips the compound off a narrow belt quickly.
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 until the whole 84 inch face is evenly damp; allow a couple of revolutions.
5. Present the edge lightly and keep the piece moving along the belt at the same steady pace used on silicon carbide. On a pencil edge, roll the profile across the full three inch face so every part of it is polished.
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, and at shift end back off the tension and leave the belt mounted or hang it. Do not fold a cork belt.

Use it for / don't use it for

Use it for

• Polishing pencil, flat and bevelled edges on shelves, mirrors, cabinet glass and shower door stiles on a 3 x 84 wet sander
• Thin lites and narrow edges where a four inch belt is wider than needed
• Bright pre-polish with pumice on edges that will be framed
• Stone, quartz, solid-surface and acrylic edges after 400 grit
• Knife and steel pre-polish with green compound on a 3 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 84 or 3 x 24 machines

Specifications

Frequently asked questions

Related products and guides

• 3" x 84" Silicon Carbide Glass Fabrication Belts, 12 pack (grinding stages before cork)
• All glass fabrication abrasives (silicon carbide belts, cork belts and discs)
• 4" x 84" Cork Sanding Belt, 6 pack, for 4 inch upright wet sanders
• 3" x 24" Cork Sanding Belt, 12 pack, for the Makita 9924DB
• Custom belt sizes, including cork, made to order in about 3 days