The word “sandblasting” gets used for almost everything in this trade, which is how people end up ordering the wrong media. Sand is sharp and angular, glass beads are round, and that one difference changes what happens to the part you are cleaning. Think of it as the difference between a chisel and a hammer. Both hit the surface, but one cuts and the other taps.
What round beads actually do
A glass bead hits the part and leaves a tiny round dimple. Millions of these dimples overlap into a smooth, matte, satin finish. Because the bead is round, it does not dig in and remove material, it peens the surface, pressing it slightly. This matters if your part has tight tolerances. We supply beads to machine shops that run the same dimension through a bead blast and still hit their prints afterwards, because the process takes off almost nothing, usually well under 0.03 mm.
Sand, or any sharp angular grit like aluminum oxide or garnet, cuts instead. Each particle acts like a microscopic knife, tearing away rust, scale, or old paint and leaving a rough profile behind. That roughness is exactly what you want before heavy industrial coating, because paint grips into it. But it is the wrong tool when the goal is a clean satin finish on a precision part.
Pressure is the whole game with glass beads
Here is the mistake we hear about most: someone runs glass beads through the same machine at the pressure they used for sand, usually 90 to 120 PSI, and wonders why the finish came out rough and dusty. Glass beads shatter when they hit too hard. Above roughly 80 PSI they break into sharp fragments, which scratch the surface and turn your “gentle” media into improvised sand. The right window for glass beads is usually 40 to 60 PSI, low enough that each bead survives the impact and stays round for the next pass.
Run at the right pressure, glass beads are reusable. Shops that keep pressure controlled report getting several cycles out of a charge before topping up, which changes the cost picture a lot over a year of daily blasting.
Where glass beads are the clear pick
Stainless steel is the classic case. Sandblasting stainless with silica or even with recycled abrasive that touched carbon steel can leave embedded iron, which rusts later under a passivation or anodizing layer. Round glass beads made from clean soda-lime glass do not carry iron, and they do not cut deep enough to trap contamination. Food-grade stainless, medical housings, aerospace trim, pre-anodize aluminum: these are all jobs where we would not push sand.
Sand and its modern replacements still win for heavy work, thick rust, mill scale, or stripping powder coat off structural steel. Glass beads bounce off heavy scale like it is not there. If the job is stripping, do not try to make glass beads do it. If the job is finishing, do not let anyone talk you into sand.
Which mesh for which look
Finer beads give a finer finish. As a rough guide, 40 to 80 mesh glass beads produce a visible matte texture, while 120 to 200 mesh give a smoother, almost satin surface that sits well under anodizing. If you tell us what material you are blasting and the finish your customer expects, we can point to a starting mesh without you running six trial bags.