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 and the hulls of boats and ships 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.


  • Prevent damage from galvanic corrosion
  • Available from 1" to 14"
  • Replaceable zinc anode
  • Soft rubber material conforms to provide a tight seal
  • In-stock items ship within 24 hours

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

Frequently Asked Questions

We are a full machine shop, and we're capable of customizing your anode plug to your exact spec. Please contact us with your project details, and we'll be happy to assist you.

The NPT on our anodes are made of brass.

Seawater, and other kinds of water, can create an electrical current between two metals that results in corrosion. By introducing a third metal that 'sacrifices' itself before the other metals start to corrode, you have an easily replaceable part that prevents corrosion on your equipment.

We suggest you check your anodes every 6-12 months.

Absolutely. We're happy to sell you just the anode, please contact us with the size of rod you need, and the dimensions on your existing plug.

Heat exchangers, pumps, tanks, pipelines and engines are all common equipment that have anode plugs built in. Boats and other equipment that are regularly subjected to seawater have a higher chance of corrosion and may benefit from a zinc anode plug.