Tips on Polishing Beach Glass With a Polishing Abrasive

Beach glass can be polished to a frosted or shiny finish with polishing abrasives.

Polishing beach glass with a polishing abrasive is best done in a rock tumbler. The polishing abrasive is available in different levels of coarseness, depending on how polished you want the beach glass. To polish the beach glass to a high shine, several levels of coarse to fine abrasives may be required. The process can take a few days to a few weeks, depending on the effect desired.

Equipment

Beach glass polishing requires either a rotary tumbler or a vibratory tumbler. The rotary tumblers are cylindrical canisters that rotate on a spindle to abrade the contents, tossing them against each other and the polishing medium. The vibratory tumblers shake the contents, vibrating them back and forth to polish them. The contents of vibratory tumblers keep their shape more than they do in rotary tumblers because they are not tossed against each other as roughly. Both machines are available in a variety of sizes, from small to large, with different motor powers. Both also run for days at a time, so place them in an area where the noise will not bother you. Check the progress every day until you become familiar with the process.

Frosting

For beach glass that retains a frosted finish but is smoother and more polished than when found, a variety of different silicon carbide grits from 60/90, which is very rough, to 120/220 grit is used. Plastic pellets are also recommended for use as a cushioning agent in the rotary tumbler so the beach glass does not chip or crack as much as it would without it. The vibratory tumbler leaves the glass with rougher edges than the rotary tumbler, but both achieve the desired frosted effect. Plastic pellets are not recommended for use in a vibratory tumbler. For a smoother surface, use finer grits.

Polishing

For beach glass with a highly polished surface, a variety of grits including silicon carbide, aluminum oxide, and cerium oxide are used. This process takes longer than leaving the beach glass frosted. Cleaning the barrel between each level of grit is much more important when using the finer grits, as any crumb of rougher grit left in the barrel causes unwanted scratches. The final steps to achieve a highly polished surface on the beach glass require the use of fine grits from silicon carbide 220 to aluminum oxide 600. For the final polish, cerium oxide or 0.5 to 1 micron aluminum oxide is recommended by Mama's Minerals, along with sugar or cornmeal as a cushioning agent.

References

• Geology: Rock Tumbler Instructions
• Rock Tumbling Supplies: FAQ
• Mama's Minerals: Tumble Polishing Glass