Metal laser cleaning: stainless steel, aluminium and rust

What laser cleaning is and when it is needed

Laser cleaning is a treatment that removes oxide, rust and dirt from the surface of a metal with a laser beam, without contact and without abrasives: the layer to be removed absorbs the beam's energy and comes away, and only the areas that need it are treated. It is sometimes called “laser sandblasting”, but it uses no sand and leaves no residue in holes, threads and crevices.

Laser cleaning is suitable when:

• a stainless steel laser welding bead needs cleaning of the discolouration left by the heat;
• a surface needs preparing before welding or painting;
• the piece has lettering, stamped marks, holes or threads to be preserved.

For a uniform matt finish over the whole piece, and for batch parts, the workshop uses bead blasting with glass beads; both are custom metalworking processes at COOLASER.

Metal laser cleaning: stainless steel and aluminium

COOLASER's metal laser cleaning works mainly on stainless steel and aluminium, the metals the workshop cuts, bends and welds most:

• stainless steel: weld discolouration, oxide, machining residues and rust stains caused by sea air on marine hardware;
• aluminium: the oxide layer and dark patinas, to be removed before welding or a new treatment;
• brass: oxidation and patinas.

Bronze can also be laser cleaned, but the workshop usually treats it with blasting; copper is not laser cleaned, because it reflects too much of the beam's light. After cleaning, the surface is left as it is or completed with satin finishing or polishing from the range of metal finishing services.

Removal of oxidation and weld discolouration

Laser oxidation removal takes off the oxide layer that forms on the metal surface over time or with heat. On stainless steel the most common case is heat tint: the yellow, blue and brown shades that welding leaves around the bead, which the beam removes without eating into the metal. On aluminium, cleaning removes the oxide before welding, because oxide left on the joint makes the bead worse. The same cleaning prepares stainless steel and aluminium surfaces before painting.

Laser rust removal

Laser rust removal takes rusty steel and cast iron parts back to bare metal, without scratching them and without leaving abrasive in hollow sections: nuts and bolts, flanges, brackets, tools and components. Deep rust is removed, but the pits it has dug remain: the laser cleans the metal, it does not rebuild what has been lost. After cleaning, the steel must be protected with paint, oil or a protective coating, because bare metal oxidises again.

CNC laser cleaning and batch parts

For cleaning batch parts, sometimes searched for as CNC laser cleaning, the workshop prefers bead blasting with glass beads, which treats the whole piece uniformly.

Metal restoration

In metal restoration, laser cleaning removes oxide and rust while preserving the shapes, edges, lettering and stamped marks of the original piece. It is used on vintage hardware and objects in brass or steel, on collectable tools and on parts of motorcycles, cars and boats. What to remove and what to keep, for example an original patina, is agreed before the work. If the piece also needs fixing, modifications and repairs can be requested.

Sizes and limits

Laser cleaning is done by hand at the COOLASER workshop, on pieces that arrive by shipping from anywhere in Italy and from abroad.

How it works

Laser cleaning is requested and delivered in three steps.

1. Request: photos, measurements and a description are sent with the online custom request, already set to finishing.
2. Quote: the workshop assesses the metal, its condition and the quantity.
3. Work and return: the piece arrives by shipping and goes back the same way or, on request, by collection from the workshop. Outside the European Union, any duties and customs charges are paid by the recipient.

What to prepare

For a laser cleaning quote, the following are needed:

• photos of the whole piece and of the areas to be cleaned (up to 10 files, 20 MB each and 30 MB in total);
• overall dimensions, the metal if known and the number of pieces;
• what to preserve (lettering, numbers, patina) and what happens next: welding, painting, assembly or display.

Without photos, measurements and a description are enough.