Subcontract bead blasting with glass beads

Subcontract bead blasting: who it is for and how it works

Subcontract bead blasting is the service in which the workshop treats the pieces the customer ships and sends them back ready for painting, assembly or delivery to the end customer. It is designed for machine shops, body shops, restorers of classic motorcycles and cars, the marine sector, metal fabricators, companies and private individuals, from one-off pieces to batches. It is one of COOLASER's custom metalworking processes and can be the last step of the subcontract production of parts cut, bent and welded at the workshop.

What bead blasting with glass beads is and when it is needed

Bead blasting with glass beads is a treatment in which small glass spheres, propelled by compressed air in a closed cabinet, strike the piece and clean its surface, leaving it matt and uniform. It is a gentle form of blasting: it removes very little material and respects edges, shapes and raised lettering. The beads are made of glass, not steel, which is why they are also used on stainless steel and aluminium. It is used for satin finishing, cleaning and preparing metal for painting.

Satin finishing of metals

Satin finishing of metals with glass beads gives a matt, uniform surface, with no directional lines, that softens small machining marks. It is a common finish on stainless steel and aluminium: laser-cut parts, brackets, flanges, turned or milled components and welded areas to be evened out, where blasting also removes the discolouration left by the heat around the bead.

Bead blasting of motorcycle and car parts

Bead blasting of motorcycle and car parts restores a clean, uniform surface to pieces that are oxidised or blackened with age, often in aluminium, provided they fit in the cabinet: carburettors, engine casings, brake callipers, hubs, levers, brackets and nuts and bolts. On pieces with internal passages, the openings to be protected are agreed first, and ultrasonic cleaning can be added afterwards to remove residue from the holes. For a detail that must not be touched, or to clean a single spot, laser cleaning may be more suitable.

Surface preparation for painting

Surface preparation for painting with glass beads removes surface oxide and dirt from stainless steel and aluminium, and light rust from steel, and leaves the metal clean, matt and uniform for primer or paint. The painting system is decided by whoever does the painting: stating it in the request helps to assess whether this finish is suitable. Freshly blasted non-stainless steel oxidises again quickly: it is best painted soon.

Cleaning and finishing of small metal parts

Cleaning and finishing of small metal parts with glass beads covers screws, bolts, nuts, washers, clips and small laser-cut components, which come back clean and with the same satin appearance. For large batches or polished surfaces, vibratory tumbling and polishing of small parts are more suitable.

Metals that can be bead blasted

Bead blasting with glass beads is used on:

• stainless steel and aluminium, to be satin finished, cleaned of oxide or prepared for painting;
• brass and copper;
• bronze, for which blasting is the treatment the workshop prefers even over laser cleaning;
• steel to be cleaned before painting.

Cabinet sizes and limits

The COOLASER blasting cabinet measures 94.5 × 60.5 × 60.5 cm inside; the maximum piece is smaller, because it has to fit in and be turned.

How it works

Subcontract bead blasting is requested and delivered in three steps.

1. Request: photos, measurements, metal and quantity are sent with the online custom request, already set to finishing.
2. Quote: the workshop assesses the pieces.
3. Work and return: the pieces reach the workshop by shipping and go back the same way, throughout Italy and abroad (outside the European Union, any duties and customs charges are paid by the recipient), or, on request, are collected from the workshop.

What to prepare

For a bead blasting quote, the following are needed:

• photos and overall dimensions of the pieces (up to 10 files, 20 MB each and 30 MB in total);
• metal and number of pieces;
• areas to be protected (holes, threads, sealing faces) and the next step, for example painting.

It is best to deliver the pieces disassembled, degreased and without bearings, gaskets or rubber and plastic parts. Without photos, measurements and a description are enough.