Two Jobs That Look the Same
Sandblasting in a laboratory does two quite different things. Divesting strips investment off a casting, which is bulk removal and wants a coarse, aggressive medium. Surface preparation creates a controlled micro-texture for bonding, which wants a fine medium and lower pressure.
Using one setting for both means either slow divesting or an over-blasted bonding surface. This is the reason twin-pen machines exist: two media, two pressures, no changeover.
Media Separation Matters
Coarse medium carried into a fine-media circuit contaminates the bonding surface and the bond becomes unpredictable. Keep the media physically separate and do not top up one circuit from the other's supply.
The Nozzle Is a Consumable
A nozzle wears from the inside. The orifice enlarges gradually, the blast pattern widens, pressure at the surface falls, and nothing announces it. The technician compensates by blasting longer, and results drift.
Replace nozzles on a schedule rather than on failure, and keep a spare. It is the single most common reason a sandblaster seems to have lost performance.
Air Supply Quality
Sandblasters need clean, dry, regulated air. Moisture carried through from the compressor clumps the medium and blocks the circuit. A water trap and regulator are part of the installation, not an optional extra.
Recycling
Recyclable machines recover and reuse abrasive. For a laboratory blasting daily, the medium saved repays the price difference; for occasional use, a standard cabinet is simpler and cheaper.
