Brass Scupper Plug
A brass scupper plug is a manually operated, threaded flow-control device that serves as a reliable stop valve for scupper drains. By tightening or loosening the plug, the user can completely seal a drain outlet to prevent water ingress or open it to allow rapid discharge. Its all-metal, heavy-duty construction makes it the preferred choice over plastic plugs in demanding marine, industrial and pool environments.
Overview
1 Material & Metallurgical Standards
Our brass scupper plugs are made from superior brass alloys that conform to international specifications:
ASTM B584 – Sand-cast or continuous-cast copper-alloy (e.g., C83600 or C84400) providing excellent strength and seawater corrosion resistance.
ASTM B16 / ASTM B124 – Free-cutting or forging brass for machined components, ensuring consistent thread quality.
DZR (Dezincification-Resistant) brass optionally available (e.g., C27453, CW602N) for highly aggressive saltwater or acidic water conditions.
2 Thread & Connection Standards
Threads are precision-cut to globally recognized specifications, guaranteeing a perfect fit and a pressure-tight seal without excessive tightening.
NPT (ANSI/ASME B1.20.1) – Tapered pipe thread standard for the North American market. The taper provides a progressively tighter seal as the plug is inserted.
BSPT / BSPP (EN 10226 / ISO 7) – British Standard Pipe Taper or Parallel threads for international vessels and equipment.
Optional O-ring groove (with EPDM or NBR ring) for enhanced low-torque sealing.
3 Design & Construction Features
One-piece body with an integral wrenching head (hexagon, square, or slotted) – no pressed-together parts, minimizing potential leak paths.
Captive chain attachment eye – Prevents accidental loss overboard when the plug is removed.
Full-port drainage (where applicable) – Smooth, unobstructed bore reduces clogging by debris.
Natural brass finish or optional nickel plating for extended cosmetic durability.
4 Performance & Compliance
Pressure rating up to 150 psi (10 bar) cold working pressure for typical sizes, verified through hydrostatic testing.
Conforms to relevant guidance found in ABYC H-27 (Seacocks, Thru-Hull Connections and Drain Plugs) where applicable, ensuring safe marine installation.
Manufactured in an ISO 9001 certified facility with full material traceability and inspection certification available on request.
5 Installation & Maintenance
Installation – Apply PTFE tape or a suitable marine sealant to the male threads. Screw in by hand until seated, then tighten no more than one-half turn with a wrench. Over-tightening may damage threads or the drain fitting.
Inspection – Periodically check for whitish surface dezincification or pitting; clean threads and replace the O-ring (if equipped) annually.
Winterization – For seasonal boats, remove or back off the plug slightly to prevent trapped water from freezing and cracking the housing.
