Collection: Flat Laps for Pumice

Pumice pre-polish is the stage between smoothing and final polish — it takes the grey haze off a smoothed glass surface and leaves it ready for cerium oxide. What you run the pumice on decides how fast that stage goes and how even the result is. These are the two laps built for it.

Which one do I need?

Synthetic felt pads (.050" thick) — optical-grade felt with a solid, unperforated face. The felt holds the pumice slurry evenly right across the disc, so the cut stays consistent edge to centre. At .050" they match the thickness of resin diamond smoothing pads, so they drop into the same lap sequence without re-setting the machine — which also makes them a good facet-work pad with cerium oxide. Four sizes: 8, 12, 18 and 24 inch.

MJ urethane laps — extruded urethane carrying fine fibres that generate friction against the glass, with an open pore structure that holds pumice in place. Faster and more aggressive than felt, and the choice for larger production work. Two sizes: 24 inch (magnetic backed) and 30 inch.

Sizes and thickness at a glance

Using them

• Match the lap diameter to your flat lap grinder platen.
• Keep the pumice wet and worked into the face — a dry lap glazes and stops cutting.
• Run pumice and cerium on separate laps. Cross-contamination is the usual cause of a polish that will not come clear.
• Rinse the lap down at the end of a session so the slurry does not set in the pores.