Barrel & Grit field manual
Can you tumble sea glass in a rock tumbler?
Sea glass can be lightly frosted or smoothed in a rotary tumbler, but the gentler goal and shorter schedule are different from polishing hard agate.
Decide on the finish first
Many collectors want a soft beach-frosted surface rather than a glossy polish. A short, gentle tumble can smooth sharp edges while preserving that character.
Use cushioning and a full barrel
Plastic pellets or suitable small media reduce hard collisions. Keep the load rolling rather than allowing large glass pieces to fall against each other.
Start conservatively
Use a gentle abrasive and inspect often. Thin or already weathered glass can lose shape quickly, so a week-long rock schedule may be far too aggressive.
Keep glass separate from stone
Do not mix sea glass with hard agate or jasper. Their different wear rates make the batch difficult to control and increase the chance of chipping.