DSS-P.04.04 — Curved/Bent Glass Local Thickness / Thinning Signatures

Curved/bent glass local thickness/thinning signatures are pane-scale shape and thickness variations inherent to thermal bending/forming. They can present as subtle local thinning or thickening zones (e.g., at tight radii or near quench/bend tooling influence) that modulate reflections/transmission without forming a worked perimeter on the exposed face. These are manufacturing attributes observed under VIS geometry; post-restoration acceptance of worked areas remains separate from factory product acceptance.

• Angle-dependent optical effects in reflected/transmitted views near bends/radii: mild brightness roll-off, localized “soft” reflective warps, or slight magnification/minification zones tied to bend geometry-no transition edge on the face.
• May co-occur with heat-treat signatures (e.g., roller/bearing influence) on bent tempered product; read strongest in raking/oblique views. Use the same VIS geometry applied to roller-wave/bow documentation.

Surface-catch class (MSRT)

• SC-0 (none) at the exposed face. Make one light, non-marring pass per VIS §5.5 to confirm no local relief; MSRT supports classification only (do not abrade).

Visual signature

• Pane-scale, non-perimeter optical shape/thickness effects contiguous with the bent geometry; no chip flanks, pits/craters, and no worked transition ring on the clear face. Use straight-line reflections (mullion/string-line/horizon) to show bending/size change across the area.

Viewing / lighting

• Evaluate clean & dry at 12 / 36 / 72 in, normal incidence and oblique sweep (~60°-120°) with raking light, per VIS.

Location / access

• Record pane ID and surface numbering (#1-#4; laminate-internal) on forms when IGUs/laminates are present.

• Processing/design feature - not field damage. If observation confirms SC-0 with pane-scale optical/shape effects and no local relief, record “Processing Feature - Not Surface Damage (outside CAT-1...CAT-4).” VIS keeps classification separate from acceptance; reserve CAT-5 for between-pane/inaccessible conditions by parallax/location.

If factory flatness/optical distortion must be quantified for product acceptance, refer to product specifications (e.g., ASTM C1036/C1048) and optical distortion background (ASTM C1651, informative). VIS governs post-restoration appearance only.

The Glass Restoration Standards...

• N/A as local relief. Local thickness/shape in bent glass is a product attribute; at the exposed face it does not present as a localized, MSRT-detectable relief feature. (Optical/flatness context aligns with VIS’s use of C1651 informatively for heat-treated distortion phenomena.)

• vs. Roller wave (P.01.01): Roller wave is periodic flatness deviation from heat-treat; bent-glass thickness signatures are geometry-driven and track the bend radius, both SC-0 at the face. Use straight-line reflections to distinguish periodic vs geometry-tied shape.
• vs. Abrasion fields (M.02): Abrasion shows directional patterning and can escalate to slight/clear catch; bent-glass thickness signatures remain SC-0 and lack a worked boundary.
• vs. Coating anomalies (Co.01/Co.03): Coating rub/patchiness is localized and disallowed at acceptance on worked coated surfaces; geometry-driven thickness signatures are pane-scale, no perimeter, SC-0.

• Photo set (VIS): 12 / 36 / 72 in; normal + oblique; include raking macros as needed; capture a straight-line reflection frame (mullion/string-line/horizon) across the bent zone to show optical/size change. Record distance/angle in-frame.
• MSRT result: Record SC-0 (one light, non-marring pass; do not abrade).
• 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: Document per VIS; factory acceptance (flatness/optical) is governed by product standards/specs; do not conflate with post-restoration appearance rules.

• P.04.04 Curved/Bent Glass - Local Thickness/Thinning Signatures (Processing Feature) - Pane-scale, geometry-tied optical/shape effect observed at VIS geometry (12/36/72 in; normal + oblique; raking). MSRT = SC-0 (no relief). No transition edge or chip-flank/pit morphology on the exposed face. Recorded as manufacturing attribute - not surface damage under VIS-DA. If fixed parallax indicates a between-pane look-alike, record CAT-5 and refer per protocol. Acceptance of any worked area per VIS §6; factory product acceptance per ASTM C1036/C1048 (optical-distortion background ASTM C1651, informative).

⭐ DSS-A

Damage Specification Standards 2026

DSS-A Assembly/Internal Conditions

Draft v1.0

A.01 IGU Cavity & Seal

• A.01.01 Internal haze/volatile fogging (#2/#3)
• A.01.02 Moisture/condensation between panes (#2/#3)
• A.01.03 Desiccant dust/fines in cavity
• A.01.04 Spacer smear/bleed inside cavity
• A.01.05 Low‐E surface corrosion within cavity
• A.01.06 Breather tube/altitude tube staining pattern

A.02 Laminated Glass Interlayer

• A.02.01 Edge haze/whitening (PVB/ionoplast)
• A.02.02 Bubbles/stringers (entrapped gas/voids)
• A.02.03 Contamination inclusions in interlayer
• A.02.04 Interlayer creep/exudation at edge
• A.02.05 Interlayer discoloration/yellowing (UV/thermal aging)
• A.02.06 Local delamination (ply/interlayer separation)

A.03 Mirrors & Back‐Coated Products

• A.03.01 Mirror edge blackening (back‐coating corrosion)
• A.03.02 Spot corrosion behind mirror
• A.03.03 Adhesive/chemical attack from behind

A.04 Switchable/Smart Glazing (PDLC/EC)

• A.04.01 Black spots/voids in active layer
• A.04.02 Busbar/lead defects visible through lite