DSS-R.05.01 — EPDM Gasket Black Rub

EPDM gasket black rub is an appearance change on glass caused by contact transfer of ethylene-propylene-diene (EPDM) glazing gaskets, weatherstrips, door sweeps, or setting blocks. It presents as grey-black smudge bands, corner arcs mirroring gasket geometry, or wipe-smeared trails where attempts were made to clean. Transfer may include carbon black, antiozonants, and surface waxes from the elastomer. Classification is appearance-only per VIS (method-agnostic). Inspect after Non-Invasive Reveal under VIS lighting/geometry; record surface numbering and worked-surface status.

• Linear smudge bands along jamb/head/sill where gaskets bear on the lite; tight corner arcs at miters.
• Door sweeps produce low horizontal bands on adjacent glazing.
• Smeared trails from dry wiping; heavier deposition at contact pressure points (hinge side, latch side).

Surface-catch class (MSRT)

• Typically SC-0 (soft transfer on top of glass).
• SC-1 may appear where dust-laden cloths or dry abrasion created very shallow micro-texture in the smudge path; SC-2 suggests misclassification (check for mechanical abrasion M-family).
• Perform one light, non-marring pass on a small revealed test patch (substrate), not over heavy soot-like deposits. Use polymer stylus if a functional coating is suspected on the worked face. MSRT supports classification only.

Visual signature

• Dark grey/black smear that mirrors gasket line; feathered outer edge and denser inner edge at contact locus.
• No chip-flank sparkle (not scoring); no discrete fused pits/nodules (not hot particle).
• May show rubber “drag commas” or micro-crumbs at starts/stops.

Viewing / lighting

• Evaluate clean & dry at 12 / 36 / 72 in, normal incidence and oblique sweep (~60°-120°); raking macros to resolve smear texture, edge feather, and contact geometry. Record distances/angles in-frame.

Location / access

• Record pane ID and surface numbering (#1-#4; laminate-internal). Most common on exposed inboard faces (#4) at operable units or doors. If fixed parallax places the mark between panes (#2/#3), classify CAT-5 by location and refer.

Mechanism cue (context)

• Fresh/aging gaskets with visible bloom, door sweep contact, operable sash compression, wind-loaded units; witness marks on gasket faces.

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

• CAT-1 (Benign / non-relief): Light smudge band; SC-0; mainly angle/raking visible. Indicative relief: 0-10 μm (optical film).
• CAT-2 (Light): Persistent dark band with localized SC-1 from prior dry wiping/soil; limited standard-view impact. Indicative relief: ~10-40 μm.
• CAT-3 (Moderate): Wide, high-contrast bands or multiple contact paths legible at standard distance, with scattered SC-1 where soil compacted. Indicative relief: ~40-120 μm.
• Reclassify when: After true residue lift, if linear scoring or micro-abrasion swirls remain → evaluate under M.01 (linear scoring) or M.02 (abrasion fields).
• 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. PVC plasticizer smear (R.05.02): PVC smears skew brown/amber with oily gloss and wetting anomalies; EPDM rub is grey/black, matte-smear and tracks elastomer contact lines.
• vs. Neoprene roller transfer (R.05.03): Neoprene often dotty/patchy with roller pitch; EPDM rub is continuous linear at gasket lines.
• vs. Silicone/PIB smears (R.01.xx): Sealant smears are oily/tacky near joints with corduroy/stringers; EPDM rub is dry-smudge exactly at gasket bearing zones.
• vs. Soot/particulate pollution (E.01.03): Soot is widespread grey/black with dry transfer; EPDM rub is localized to contact geometry.

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique; raking macros of smear edge, contact line, corner arcs; context frames of gaskets/sweeps contacting the lite. Record distance/angle in-frame.
• MSRT result (substrate): After a small reveal test 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.05.01 EPDM Gasket Black Rub - Grey-black smudge band/arc aligned to gasket contact on surface #___; post-reveal test patch shows [SC-0/SC-1]; visible at [12/36/72 in] under VIS geometry. Morphology: feathered smear, corner arcs, no chip-flank sparkle, no pits. Classification: CAT-[1/2/3] by visibility and SC-class; CAT-5 if between-pane or coating-side loss on the surface to be worked. Forms + photo set attached; acceptance per VIS-A §6.