The Golden Rule: If You Can't Identify It, Don't Laser It
Is it safe to laser a material I can't identify?
No. Mystery plastic, unknown coatings, galvanised or plated metal of unknown origin, 'wood' sheets with resin faces — unknown means assume unsafe. The two biggest hidden dangers are chlorine (PVC hides everywhere) and zinc coatings on galvanised steel, which produce fumes that cause metal fume fever.
Hides inWhere it turns up
Everything without a material spec: charity-shop finds, offcut bins, imported blanks with no datasheet, coated boards, painted anything.
InsteadSafe alternatives
Ask the supplier for a material spec or safety data sheet (SDS). Check recycling codes — #3 is PVC. Buy laser-grade blanks from laser suppliers. When in doubt, leave it out.
If it happensAccidental exposure
If something smells wrong or smokes strangely mid-job: stop, ventilate, and identify before continuing. Trust your nose — chlorine's acrid bite and melting plastic are warnings.