USA Industries Zinc Plugs, Zinc Anode, Marine-Zinc, Pencil Zinc

Other Names/Uses

  • Boat Pencil Zincs, Pencil Anodes, Engine Anodes, Marine Zincs, Zinc Engine Anodes, Pencil Zinc Engine Anodes, Galvanic Corrosion Anodes, Galvanic Sacrificial Anodes

Zinc Anode Header Plugs (Sacrificial Anodes)

Reduce Corrision and Prevent Equipment Damage with Sacrificial Zinc Anodes


Sacrificial Anodes are found in refineries, heat exchangers, water heaters, pipelines, distribution systems, above-ground tanks, underground tanks, the hulls of boats and ships, and car engine cooling systems to protect dissimilar metals from corrosion.

Because heat exchangers are typically a copper alloy, they are at risk of galvanic corrosion. To combat this, many heat exchangers are fitted with Zinc Anode Header Plugs. You will find it (or not) under a plug in the exchanger. The Zinc Anode Header Plug is easily replaced by unscrewing the old sacrificial anode from the plug.

If your equipment is fitted with internal anodes, check them annually.

Why do sacrificial anodes help?

Any time two different metals that are physically or electrically connected and are near seawater, will become a battery. Some amount of current flows between the two metals. The electrons that make up that current are supplied by one of the metals giving up bits of itself in the form of metal ions to the seawater. This is called galvanic corrosion and if left unchecked, will quickly destroy the metals.

To counteract galvanic corrosion a third metal that is quicker than the other two metals is into the circuit to give up its electrons.

Replacement anodes are available without purchasing plug.

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  • Prevent damage from galvanic corrosion
  • Rod lengths available from 1" to 14"
  • Rod diameters available from 1/4" to 1"*
  • Replaceable zinc anode
  • Soft rubber material conforms to provide a tight seal
  • In-stock items ship within 24 hours

For sizes larger than 1" NPT, use 1" parts and install a reducing bushing

For use in heat exchangers, pumps, tanks, pipelines and engines

Zinc Corrosion Plug Specifications
Size NPT (in.) Rod Diameter (in.) Rod Length (in.) Part No.
1/4 1/4 1 AP-0250-1
1/4 1/4 2 AP-0250-2
1/4 1/4 3 AP-0250-3
1/4 1/4 6 AP-0250-6
3/8 3/8 2 AP-0375-2
3/8 3/8 3 AP-0375-3
3/8 3/8 6 AP-0375-6
1/2 1/2 3 AP-0500-3
1/2 1/2 6 AP-0500-6
1/2 1/2 8 AP-0500-8
3/4 3/4 4 AP-0750-4
3/4 3/4 6 AP-0750-6
3/4 3/4 8 AP-0750-8
1 1 4 AP-1000-4
1 1 6 AP-1000-6
1 1 1 AP-1000-10
1 1 14 AP-1000-14

Frequently Asked Questions

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