DSS-Th.01.01 — Welding Slag Spatter (fused nodules/pits)

Welding slag spatter presents as fused metallic nodules and/or resultant pits/craters formed when hot particles (weld spatter) impact and partially fuse to the glass, often followed by detachment leaving a pitted field. Classification is appearance-only per VIS; methodology is out of scope. Inspect under VIS lighting/geometry after Non-Invasive Reveal; record surface numbering and worked-surface status on Forms: Use the Manual Surface-Relief Test (MSRT) only as a single, non-marring pass to confirm relief; it does not determine acceptance.

• Peppered field of dark or metallic specks; some remain proud/fused, others have detached, leaving bright, crater-like pits with halo in raking light.
• Often clustered on elevations adjacent to welding operations (balustrades, canopy frames, stair rails).
• May coexist with grinding sparks (ferrous “pepper”) and heat tinting on nearby metals.

Surface-catch class (MSRT)

• On fused nodules, a light, single pass typically yields SC-2 (clear); on detached pits, SC-1 to SC-2. Do not abrade; one non-marring pass only; polymer stylus if a coating is suspected.

Visual signature

• Discrete, high-contrast nodules (sometimes metallic sheen) and sharp-edged micro-craters; bright chip-flank sparkle at pit edges under raking.
• Fields may show directional bias toward the source; individual pits do not track as continuous lines (distinguishes from linear scoring).

Viewing / lighting

• Evaluate clean & dry at 12 / 36 / 72 in, normal incidence and oblique sweep (~60°-120°) using raking light to reveal relief.

Location / access

• Record pane ID and surface numbering (#1-#4; laminate-internal). If parallax or construction indicates a between-pane condition, classify CAT-5 by location (out of in-place scope).

Mechanism cue (context)

• Welding slag / grinder overspray is a typical origin for severe mechanical-thermal fields. (Informative linkage from VIS category notes.)

Assign CAT by appearance + MSRT + morphology (three-part cueing). Numeric depth bands are indicative only-measurement is not required for classification.

• CAT-2 (Light): Sparse nodules/pits; SC-1 (slight) to SC-2 (clear) on a few features; visible mainly in raking at close/standard view. Indicative depth: ~20-60 μm (pit diameter typically ≤0.3 mm).
• CAT-3 (Moderate): Clustered field, numerous clear-catch pits with bright flanks; noticeable at standard distance. Indicative depth: ~60-150 μm; mixed nodules and detached pits.
• CAT-4 (Severe): Dense peppering / crater field, frequent fused nodules with rough micro-flanks, occasional micro-fracture lips at pit margins; visible at standard & wide-field. Indicative depth: ~150-400 μm+.
• CAT-5 (by location/condition): Between-pane cues, active cracks, pane movement, or coating-side loss on the surface to be worked → CAT-5 (non-repairable/out of in-place scope).

CAT is appearance-based; acceptance is separate and governed by VIS §6 at 12/36/72 in under defined conditions.

• vs. Grinder spark embed (Th.01.02): Grinder pepper tends to be finer, more uniform; welding slag shows larger, irregular nodules/pits with higher local energy signatures.
• vs. Sand abrasion (E.02.01): Eolian matte is broad, directional micro-texture (field haze) rather than discrete fused droplets.
• vs. Coating anomalies (Co.01/Co.03): Coating rub/patchiness lacks fracture facets/pits and shows sheen/color shifts rather than fused bodies; also governed by coated-surface acceptance rules on the worked surface.
• vs. Linear scoring (M.01): Scores form continuous tracks; slag presents as discrete peppering without long run-length.

• Photo set (VIS): 12 / 36 / 72 in; normal + oblique; include raking macros resolving facet/halo at representative pits and at least one context frame showing proximity to weld source. Record distance/angle in-frame.
• MSRT result: One light, non-marring pass on a representative nodule/pit; SC-class = SC-1/SC-2 as observed; polymer stylus where a coating is suspected.
• 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 §6 at 12/36/72 in; classification ≠ acceptance. Coating anomalies on a worked coated surface remain disallowed at acceptance per VIS §6.2.e.

• Th.01.01 Welding Slag Spatter - Discrete fused nodules / pits on surface #___ documented at 12/36/72 in, normal + oblique with raking; MSRT = SC-[1/2] on representative features. Morphology shows peppered field with crater halos; no continuous linear scoring observed. Classification: CAT-[2/3/4] by density and relief; CAT-5 if between-pane, active cracks, or coating-side loss on the surface to be worked. Forms + photo set completed; acceptance per VIS §6 (separate).