DSS-R.06.01 — Aluminum Rub / Grey Smear

Aluminum rub / grey smear is an appearance change on glass caused by mechanical contact with aluminum components (frames, extrusions, setting blocks/shims, ladders, straightedges, glazing tools) that leave a metallic grey transfer film. It typically tracks linear contact paths at frame interfaces or along tool routes. Classification is appearance-only per VIS (method-agnostic). Inspect after Non-Invasive Reveal under VIS lighting/geometry; record surface numbering and worked-surface status.

• Cool grey, matte-metallic smear with a directional drag-often linear along jamb/head/sill or straightedge paths.
• Heavier density at start/stop or pressure points; feathered fringes where cloths smeared the transfer.
• May co-occur with fine oxide dust on adjacent aluminum.

Surface-catch class (MSRT)

• Typically SC-0 (transfer film on top).
• SC-1 appears where dry wiping with dust created very shallow micro-texture within the smear; SC-2 suggests misclassification-check for M.01 linear scoring.
• Perform one light, non-marring pass on a small revealed test patch (substrate). Use polymer stylus if a functional coating is suspected. MSRT supports classification only.

Visual signature

• Neutral/cool grey metallic tone (not oily amber); directional smear geometry; no discrete pits/nodules.
• No chip-flank sparkle (not an incision) under raking.

Viewing / lighting

• Evaluate clean & dry at 12 / 36 / 72 in, normal incidence and oblique sweep (~60°-120°); raking macros to show drag direction and smear boundary. Record distances/angles in-frame.

Location / access

• Record pane ID and surface numbering (#1-#4; laminate-internal). If parallax shows the smear between panes (#2/#3), classify CAT-5 by location and refer.

Mechanism cue (context)

• Fresh aluminum work, unprotected straightedges, frame adjustments, ladder contact, glazier tools; aluminum oxide residue on frames.

Assign CAT by visibility at acceptance geometry and MSRT after a small reveal test. Depth values are indicative-field measurement not required.

• CAT-1 (Benign / non-relief): Light metallic smear; SC-0; mainly angle/raking visible. Indicative relief: 0-10 μm (optical film).
• CAT-2 (Light): Persistent grey smear with localized SC-1 from prior dry wiping; limited standard-view impact. Indicative relief: ~10-40 μm.
• CAT-3 (Moderate): Broad, high-contrast smears/bands legible at standard distance, with scattered SC-1 where soil compacted. Indicative relief: ~40-120 μm.
• Reclassify when: After true residue lift, any incised lines with chip-flank sparkle or SC-2 persist → evaluate under M.01 (linear scoring).
• 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. Do not abrade to “force” removal during classification.

• vs. EPDM gasket rub (R.05.01): EPDM is black/charcoal and tracks gasket lines; aluminum is cool grey metallic and tracks metal/tool contact paths.
• vs. PVC plasticizer smear (R.05.02): PVC is amber/oily with wetting anomalies; aluminum is dry grey without oil beading behavior.
• vs. Steel/ferrous rub (R.06.02): Ferrous rub skews darker/black, may stain fingers, and can show brown oxidation; aluminum remains light grey.
• vs. Hot-particle embed (Th.01.02 ferrous peppering): Hot particle shows micro-pits/fused nodules and local SC-2; aluminum rub is film-like with SC-0/SC-1 and no pits.

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique; raking macros of smear edges and drag direction; context frames showing aluminum components/tools. Record distance/angle in-frame.
• MSRT result (substrate): After a small reveal patch, perform one light, non-marring pass; record SC-class (SC-0/SC-1/SC-2).
• 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; 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.

• R.06.01 Aluminum Rub / Grey Smear - Cool grey metallic smear tracking metal/tool contact on surface #___; post-reveal test patch shows [SC-0/SC-1]; visible at [12/36/72 in] under VIS geometry. Morphology: directional drag, feathered edge, no chip-flank sparkle, no pits. Classification: CAT-[1/2/3] by visibility and SC-class; reclassify to M.01 if incisions persist; CAT-5 if between-pane or coating-side loss on the surface to be worked. Forms + photo set attached; acceptance per VIS-A §6.