Coated Metals: Diode
A diode laser ablates dye and coatings cleanly without touching the metal underneath. Anodized aluminum, powder-coated tumblers, painted metals, all in scope.
Anodized aluminum
Hard-anodized Type III with dye in the oxide layer. Diode ablates the dye, exposing white aluminum oxide.
| Black anodized | 2000-3000 mm/min · 25-40% · 1 pass · 0.08 line |
| Red / blue anodized | 2500 mm/min · 30-45% · 1 pass · 0.08 line |
| Photo on dark anodized | 3000 mm/min · 20-30% · Jarvis dither · 0.10 line |
Lighter anodize colors (silver/gold) are harder, less dye to ablate. Test on the inside of the part first.
Powder-coated tumblers
The most popular diode metal job. Black, white, or color tumblers with a powder-coat layer 50-100µm thick.
| Logo / single-color engrave | 1500-2500 mm/min · 30-45% · 1 pass · 0.10 line |
| Photo on tumbler | 2500 mm/min · 25-35% · Stucki dither · 0.10 line |
Use a rotary attachment (most diode brands sell these) for cylindrical tumblers. The DOF tolerance is enough for the cylinder curve.
Cerakoted firearms
- Diode ablates Cerakote cleanly without scoring the metal underneath.
- Settings: 1500 mm/min, 35-50% power, single pass, 0.10 line.
- Goal: clean ablation, no metal scoring (preserves re-coat-ability).
- Test on a hidden area first, Cerakote thickness varies.
Painted metal (Zippos, signs, art panels)
Diode ablates paint cleanly; effect varies by paint composition.
- Acrylic enamel / lacquer paints, clean ablation.
- 2-part epoxy paint, ablates but slower.
- Chrome paint / metallic finishes, reflective; lower power required.
- Settings: 2000 mm/min, 35-45%, single pass.
Bare metal: diodes need help
Diode can't directly mark stainless / aluminum / brass / copper because of insufficient absorption at 450nm. Use marking spray:
| Spray | Best for | Settings |
|---|---|---|
| LBT-100 | Stainless steel, titanium | 1500 mm/min · 90% · 1 pass |
| CerMark / TherMark | Bare aluminum, brass | 1500 mm/min · 90% · 1 pass |
| CRC Dry Moly Lube | Cheaper CerMark alternative, lighter mark | 2000 mm/min · 85% |
Workflow: spray light coat → let dry → mark → wipe off residue.
Common projects on coated metals
- Tumblers: rotary + powder coat ablation. $20-40 retail per piece.
- Pet tags (anodized AL): easy volume seller. $5-15.
- Glock backplates: slip-on aftermarket plates with coating to ablate. $20-45.
- Apple Watch bands (anodized): premium personalization. $15-35.
- Painted Zippos: diode handles painted Zippos well. $25-65.
- Custom keychains (anodized AL): bulk friendly. $8-18.
What diodes can't do on metals
- Color anneal stainless or titanium (fiber MOPA only).
- Deep engrave bare metal (fiber).
- Photo engrave on bare polished metal.
- Cut metal of any thickness.
- Mark mirror-polished or reflective surfaces (silver, polished brass) without spray.