(these cannot be cut only engraved or marked)
The materials included in this section tend to have a binary colour scheme when laser marked. I.e. you have the natural colour of the material and you have a different colour/finish when laser marked. Repeated marking with the laser will not change the colour, only remove material. In some cases, small beads of glass can be formed due to the extreme temperatures attained. Many of these materials are great substrates for photoengraving.
Stone, Pebbles, Slate, Marble, Granite, Soapstone, Onyx
Stone and similar materials can be engraved to great effect with a CO2 laser machine. The laser removes the top surface, leaving behind a light grey textured surface. Subsequent laser marking will not alter this colour, just remove additional material.
Glass
Glass can be engraved but not cut with a CO2 laser. The surface is locally heated by the laser beam causing minute fractures and particles of the glass to break free. Think “Crazy Paving” for the textured effect. While the effect is limited to the surface of the glass (less than 0.1mm / 0.004″) you will get particles of loose glass. So engraving should be done on the reverse of clear glass (reverse image) or brushed and coated to minimise the risk from the glass particles. If the mark needs to be on the front facing surface, my preference is to use Cermark/Thermark/Dry Moly spray to give a black mark on the glass. Toughened glass engraves in a similar manner, but be careful not to put too much heat into one spot as it could cause it to shatter.
Anodised Aluminium (Aluminium Oxide)
Technically you are not engraving the Anodised Aluminium, you are in fact vaporizing the pigment revealing the natural light grey anodised surface. Repeated engraving of the same spot does not change the colour or remove material, making anodised aluminium a fantastic substrate for photographic engraving.
Painted, coated metals
Technically you are not engraving the Painted, coated metal, you are in fact vaporizing the paint or coating, revealing the bare metal underneath. Care must be taken to ensure you do not engrave directly onto bare metal as the reflection of the laser beam can damage the lens.
There are three coatings commonly applied to metals (they’re also good for glass, ceramics and stone) and they each work in the same manner. Namely, you spray the coating onto a clean dry surface and allow it to dry. You laser engrave the coated surface and wash away the untouched residue, leaving a black mark on the surface.
- Cermark
- Thermark
- Dry Molybdenum Disulphide Lubricant spray: About 20% of the cost compared to the others, but the mark is not as dark.
Glass Mirror
The CO2 laser beam can only engrave the surface of the glass and will not affect the silver mirror finish. If you are looking for a specific effect, you could consider engraving mirrored acrylic instead. NB: you will need to use a fibre laser to directly engrave the mirrored surface on a glass mirror. The fibre laser beam will pass through the glass and interact with the silver coating. Silver backed, clear acrylic may be an option.
Ceramics
Ceramics can be engraved to great effect with a CO2 laser machine. The laser removes the top surface, leaving behind the natural textured base material. Subsequent laser marking will not alter this colour, just remove additional material. Some specialist tiles have a ceramic coating that changes colour and is not removed when laser marked. You can also coat the ceramic with Thermark/Cermark/Dry Moly spray, engrave and get a black mark.