🤔 Materials that probably shouldn't be used
There are some materials that, whilst not on the banned list,
are problematic in other ways and should be avoided:
Oily or resinous wood
Pine, cedar, eucalyptus or teak woods have a high resin or oil content and will char excessively. They may ignite easily. Use untreated hardwoods such as maple or birch instead.
Reflective metals (not mirror-finished)
Aluminium, brass and copper may reflect the laser back along the optical path and cause damage to the machine. Metals will not cut using a CO2 laser. If engraving, use a laser safe coating and lowest effective power.
Corrugated cardboard
Air pockets within the corrugations increase fire risk. Monitor the cut or engraving carefully and continuously.
Layers of the same items, unglued (e.g. a stack of paper)
Air pockets within the laminations increase fire risk. Avoid cutting or engraving unglued layered materials.
Foam board (paper-foam-paper laminate)
Foamboard will cut nicely on the laser, but... The paper coating will scorch, and the foam layer will shrink away from the cut leaving unsupported edges. There is a greater risk of fire due to the lamination and melting plastic.