Use the Symbol Builder tab to build a weld callout by selecting the weld type, side, and filling in dimensions. The symbol preview and all three interpretation panels update live as you type — no submit button required. Click Load Example to see a fully-populated 1/4" fillet, both sides, staggered, GMAW callout. Click Reset to clear everything back to defaults. Use Print Summary to print or export the symbol and interpretation as a one-page landscape PDF.

The horizontal line is the reference line. The angled line with the arrowhead points to the joint being welded. Per AWS A2.4: symbols placed below the reference line apply to the arrow side; symbols placed above apply to the other side. The forked tail at the right carries process codes, WPS references, and notes. The all-around circle at the elbow means weld the full perimeter. The filled field weld pennant at the elbow means the weld is made on site, not in the shop.

Fillet: right-triangle symbol; T-joints, lap, corner.
V-groove / Single-bevel: full or partial penetration butt welds.
U-groove / J-groove: curved prep; less distortion, less filler.
Flare-V / Flare-bevel: rounded surfaces — tubes, bent plates.
Plug / Slot: hole or slot filled with weld metal; lapped members.
Spot / Seam: resistance or arc spot/seam; no edge prep needed.
Surfacing: built-up deposit for wear resistance or restoration.
Back/Backing: reverse-side weld on a single-groove joint.
Edge: welds along edges of parallel or near-parallel members.

Left of symbol: weld size (fillet leg size; groove weld size). Depth of prep, if different from size, appears in parentheses to the left.
Right of symbol: length and pitch as length–pitch (e.g. 3–6 = 3" welds on 6" centres). Omit length for continuous welds.
Groove dims (angle, root opening, throat) stack between the weld symbol and the contour symbol, reading outward from the reference line.
Quantity ×N appears above/below the length-pitch and is used for spot, plug, and slot welds.

Groove angle: included angle between prepared faces (e.g. 60° for a V-groove, 45° for a bevel).
Root opening: gap between members at the joint root before welding (e.g. 1/8"). Controls burn-through risk and penetration.
Depth of prep: for PJP groove welds — depth of the prepared groove, shown in parentheses to the left of the symbol.
Effective throat: shortest distance from the root to the face; governs strength calculations. For PJP grooves this is typically less than the depth of prep.

Contour symbols stack on the same side as the weld symbol, beyond any groove dims:
Flush (─) = weld face flush with base metal surface.
Convex (⌣) = crowned / raised face above the surface.
Concave (⌢) = hollowed / recessed face below the surface.
The finish method letter stacks beyond the contour:
G = grind  ·  M = machine  ·  C = chip
H = hammer  ·  R = roll  ·  U = method unspecified
A finish letter without a contour will generate a validation warning.

When Staggered is checked and Both Sides is selected, the STAG marker appears above the reference line. Staggered intermittent means weld segments on one side are offset by half a pitch from segments on the opposite side. This distributes heat input, reduces distortion, and is common on T-joints and lap joints in thin material. Staggered on a single-side callout is unusual and will trigger a validation warning.

The Melt-Through (MT/BK) annotation indicates complete joint penetration is required with visible root reinforcement on the opposite side — used on single-welded groove and flange welds where full penetration must be verifiable from the back. It is not applicable to surfacing welds. When a separate backing bar or backing ring is used (rather than melt-through), it is better practice to note it in the tail rather than using the MT/BK annotation.

The All Around circle at the arrow elbow indicates the weld runs continuously around the entire perimeter of the joint — common on tubular connections, structural posts, and pipe fittings. The Field Weld filled pennant flag at the elbow (standing above the reference line) indicates the weld is not made in the fabrication shop — it is made at the erection site or in the field. Shop welds have no flag. Both symbols can appear simultaneously.

The forked tail at the right end of the reference line carries supplementary information: process codes (GMAW, GTAW, SMAW, FCAW), WPS references, filler metal designations, or shop notes. Long tail notes wrap automatically in the symbol view. Use the checkboxes for common annotations — Seal, TYP, Melt-Through — to add them without manual typing. No tail is drawn unless at least one tail field is populated. The Tail Text free-form field accepts any annotation.

This tool targets AWS A2.4 (Standard Symbols for Welding, Brazing, and Nondestructive Examination) as used in U.S. shop and structural fabrication, consistent with SolidWorks and AutoCAD weld symbol conventions. ISO mode adds a dashed identification line above the reference line per ISO 2553 as a visual reference only. This tool is a communication and quoting aid — not a certified drafting output. Always confirm critical weld callouts with a qualified welding engineer, CWI, or AWS-certified documentation for structural, pressure vessel, or code-governed work.

Press Print Summary to send the current symbol and interpretation to your printer or PDF export. The print layout hides all controls and renders the symbol + interpretation in landscape orientation, formatted to fit an A4 or Letter page. The FabEngineer Pro logo appears in the header. Use your browser's "Save as PDF" option to create a shareable document.

FabEngineer Pro — Weld Symbol Builder / Interpreter
Version 1.0  ·  Initial Release  ·  Reference standard: AWS A2.4 / ISO 2553 (reference only)
For shop communication, quoting, and drafting assistance.
Not a substitute for certified welding documentation.

Revision History
Rev 1.0 — Initial release.
All 15 AWS weld types with corrected geometry.
Contour/finish stacking, groove dims, tail auto-wrap.
Field weld flag, all-around, staggered, melt-through.
Notes reference tab. Print landscape one-page.
AWS A2.4 layout. ISO dashed-line mode. Squarespace-compatible.