DSS-Ch.06.02 — Hydrophobic Coating Mismatch Halo

Hydrophobic coating mismatch halo is an appearance change caused by uneven application, partial removal, or edge-lap of an on-glass hydrophobic coating (e.g., rain-repellent, DIY nano-sealant). The result is a water-behavior discontinuity and an optical halo/veil at the boundary between coated and uncoated (or differently coated) zones; long UV/soil exposure may leave very shallow micro-texture at the boundary. Classification is appearance-only per VIS (method-agnostic). Inspect after Non-Invasive Reveal under VIS lighting/geometry; record surface numbering and worked-surface status. If the worked surface is a functional factory coating, see coated-face acceptance limits (VIS §6.2.e).

• Sharp arc/rectangle/roll-stop lines or hand-wipe arcs seen as darker/lighter halos in specular view; often mirrors applicator paths (pad/cloth/roller).
• Water-break test reveals different wetting angles: beads tightly on one side, sheets on the other.
• Over time, the boundary may become a “dirty tide line,” with preferential soil load where chemistry differs.

Surface-catch class (MSRT)

• Typically SC-0 (film/wetting difference only).
• SC-1 (slight) can appear on aged/UV-baked boundaries where organics cross-link with dust/soot; SC-2 uncommon.
• Perform one light, non-marring pass on a revealed test patch; use a polymer stylus if a functional coating is suspected. MSRT supports classification only.

Visual signature

• Crisp boundary geometry that tracks application (arcs, rectangles, roll starts/stops, cloth edges).
• Optical halo/veil adjacent to the line; no chip-flank sparkle (not mechanical) and no discrete pits/nodules (not hot-particle).

Functional cue (water behavior).

• Contact-angle contrast (beading vs. sheeting) straddling the line. Document with controlled misting photos (do not flood IGU edges).

Viewing / lighting

• Evaluate clean & dry at 12 / 36 / 72 in, normal and oblique sweep (~60°-120°); use raking light for veil/boundary. Record distance/angle in-frame. Add wetting test images as supplemental evidence (see forms).

Location / access

• Record pane ID and surface numbering (#1-#4; laminate-internal); if fixed parallax indicates between-pane wetting contrast (e.g., factory low-E vs. cavity contaminant), classify CAT-5 by location and refer.

Mechanism cue (context)

• Presence/history of consumer/hydrophobic coatings, contractor “sealants” on glass, partial removal, or mock-ups. Look for applicator tools and masking patterns.

Assign CAT by visibility impact and MSRT after reveal. Depth values are indicative-field measurement not required.

• CAT-1 (Benign / non-relief): Water-behavior edge/optical halo only; SC-0; visible mainly at angle or with wetting test. Indicative relief: 0-10 μm (optical).
• CAT-2 (Light): Persistent halo/veil with slight SC-1 at aged boundary; limited impact at standard view. Indicative relief: ~10-40 μm.
• CAT-3 (Moderate): Broader boundary zones legible at standard distance (dirty tide line, non-uniform sheen) with SC-1→SC-2. Indicative relief: ~40-120 μm.
• CAT-4 (Severe): Rare for hydrophobics alone; if extensive matte fields occur, consider mixed chemistry (alkaline + coating residue + UV/soiling) and re-evaluate under applicable DSS. Indicative relief: ~120-300 μm+.
• CAT-5 (by condition/location): Between-pane/inaccessible by parallax, integrity indicators, or confirmed functional-coating loss on the surface to be worked → CAT-5.

CAT is appearance-based; acceptance is separate under VIS-A at 12/36/72 in. For factory functional coated faces, see VIS §6.2.e (appearance on worked coated surfaces).

• vs. Silane/siloxane migration halo (Ch.06.01): Migration halos align with masonry treatment lines/weep paths; hydrophobic mismatch halos align with applicator geometry on the glass field and are confirmed by wetting contrast.
• vs. Mineral staining/etch (Ch.03): Mineral issues show rings/runs and modeled micro-texture; mismatch halos are sharp wetting edges with usually SC-0 substrate.
• vs. Residue films (R-family): General films lack sharp water-behavior lines and often clear uniformly at reveal.
• vs. Coating anomalies (Co-family manufacturing): Factory coating rub/patchiness follows production/handling logic and may appear on #2/#3 faces; hydrophobic mismatch is field-applied and resides on the exposed face.

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique; include raking macros of the boundary line and adjacent veil. Record distance/angle in-frame.
• Wetting behavior documentation (supplemental). Light mist test across the boundary; photograph immediate beading/sheeting contrast. Avoid flooding edges/IGU seals.
• MSRT result: One light, non-marring pass on a clean test patch at/near the boundary; record SC-class (SC-0/SC-1/SC-2). Polymer stylus if a factory functional coating may be present.
• Forms: Pane ID; product family & surface numbering; worked surface Y/N; functional coating present on worked surface? (Y/N/Unknown); reveal status; lighting/time; geometry checklist; wetting test photos attached.
• Acceptance split: Post-restoration acceptance per VIS-A §6; classification ≠ acceptance. Coated-face appearance rules apply per VIS §6.2.e when the worked surface is a factory functional coating.

• Ch.06.02 Hydrophobic Coating Mismatch Halo - Sharp wetting-behavior boundary with optical halo on surface #___; mist test shows beading vs. sheeting across the line. Post-reveal test patch reads [SC-0/SC-1]; visible at [12/36/72 in] under VIS geometry. Morphology: roll/cloth arc or edge-lap line, no chip-flank sparkle, no discrete pepper. Classification: CAT-[1/2/3/4] by visibility/SC-class; CAT-5 if between-pane, integrity cues, or coating-side loss on the surface to be worked. Forms + photo + wetting documentation attached; acceptance per VIS-A §6.