


Could "hard well water" form raised, acid-insoluble nodules on PVD stainless steel, or is this a synthetic polymer?
Substrate / Material Details:
- Substrate: 304-Grade Stainless Steel (18/8 Cr-Ni alloy)
- Surface Finish: Dark PVD (Physical Vapor Deposition) titanium-based ceramic nano-coating (Lefton brand sink)
- Age / Usage: Brand-new installation; spots were present post-remodel.
Physical Characteristics of the Residue:
- Localized, opaque white droplets/bumps.
- Distinct, tangible raised edges (readily caught with a fingernail or plastic edge).
- Visually darkens/disappears under refractive liquid/oil, but physical texture remains.
- General contractor claims these are standard "hard well water mineral deposits."
Chemicals Tested & Results:
| Product Used | Active Chemical Compounds | Exposure Time | Observed Result |
|---|---|---|---|
| CLR (Calcium Lime Rust) | Lactic Acid (C3H6O3), Gluconic Acid (C6H12O7), Lauramine Oxide surfactant | ~5 min direct contact / scrub | Zero effect. No effervescence, no dissolution, no softening. |
| Pure Acetone | Dimethyl Ketone / Propan-2-one ((CH3)2CO) | 2–3 min surface contact (rag) | Zero effect. Did not dissolve or wipe away. |
| Hope's Perfect Sink | Fine mineral abrasive slurry, surfactants, silicone/polymer conditioner | Mechanical buffing | Only masks surface optically; does not remove physical bumps. |
Questions for Chemists / Material Scientists:
- Inorganic / Mineral Solubility: Is there any plausible scenario where potable well water precipitates calcium carbonate (CaCO3), magnesium carbonate (MgCO3), or calcium sulfate (CaSO4) into discrete, raised nodules that show zero reactivity or dissolution when exposed to concentrated lactic and gluconic acids (pH ~2.5)?
- Silicate Scale vs. Organic Polymer: Even in high-silica well water (SiO2), can silica scale form localized, raised droplets with defined edges in under 3 weeks of light domestic use?
- Polymer / Trade Splatter Hypothesis: Given the insolubility in alpha-hydroxy acids and resistance to brief ketone exposure, does this profile point almost exclusively to cross-linked organic polymers (e.g., 2-part epoxy grout, polyurethane/acrylic mastic, cured silicone, or solvent-based penetrating tile sealer) from the remodel?