Rainbow Finish – What is it in Vaping?

Definition

Rainbow Finish is a multi-coloured, iridescent surface coating applied to stainless-steel or aluminium vape hardware—most commonly seen on RDAs, RTAs, RDTAs, mods, drip tips and refillable tanks. Created through a controlled electro-chemical passivation process (often called PVD or anodising), the metal is oxidised in micro-layers that refract light, producing shifting hues of turquoise, magenta, gold and green without adding paint or dye. Beyond pure aesthetics, the thin ceramic-like layer increases scratch resistance and limits corrosion, keeping 510 threads, clamp posts and airflow caps looking fresh under heavy Australian vaping conditions.

Technical Details

The colour spectrum is achieved by applying 12–48 V DC across the component while it is submerged in a hot electrolyte bath; oxide thickness grows roughly 25–85 nm per volt, and each nanometre range reflects a different wavelength. Typical specifications:

  • Coating thickness: 0.2 – 1.0 µm
  • Surface hardness: 600 – 900 HV (2–3× untreated 304 SS)
  • Temperature tolerance: –40 °C to 280 °C, safe for dry-burning coils up to 30 W
  • Electrical resistance: still conductive; finish does not affect resistance readings on RDA/RTA builds

Common variants include high-polish “mirror rainbow”, matte “oil-slick”, brushed “spectrum” and fade two-tone. Manufacturers may label them PVD, titanium anodised, or simply “rainbow”, but all rely on the same interference-layer physics.

Usage & Tips

  • Cleaning: Use warm water, mild detergent and a soft toothbrush; avoid chlorine or citrus agents that pit the oxide.
  • Building: When mounting coils on a rainbow RDA/RTA, tighten screws firmly—metal-on-metal contact strips the colour, so consider silver-plated posts if you re-wick often.
  • Heat: Prolonged glowing above 350 °C can dull the sheen; pulse coils at 20–25 W when testing resistance.
  • Safety: The finish is inert and non-toxic, but if flaking occurs (rare), replace the part to prevent inhaling metallic flecks.

History & Context

Vape “rainbow” finishes emerged around 2014 when high-end modders borrowed titanium anodising techniques from the aerospace industry to differentiate handcrafted RDAs. Mainstream Chinese manufacturers adopted PVD batch coating by 2016, making rainbow hardware affordable and cementing it as a staple aesthetic in Australian vape shops alongside classic stainless and black devices.

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