Zinc Anode Caps for Cathodic Protection Systems

Uses: Zinc anode caps should be used on pipeline fittings, valves, flanges and bolts. The use of anodes will greatly improve the corrosion resistance of steel, ductile iron and cast iron hardware.

Zinc Caps

Northtown zinc anode caps are engineered to fight corrosion. When the caps are threaded onto the bolts or studs, they become sacrificial anodes and protect the flanges, mechanical joints and other metal parts. Our zinc anode caps are precision made of the highest grade metal which meets or exceeds the requirements of ASTM B-418-80,88 and MIL spec MIL-18001H,J,K.

Corrosion of underground mechanical joint fittings may prove to be very costly, both in repair costs to pipelines and the untimely interruption to the vital flow of water, oil or gas. Most failures of pipelines can be directly related to the flange area where the two ends of the pipeline are attached by a stud/bolt nut joint. Northtown zinc anode caps are designed to sacrifice themselves rather than allowing the underground water, oil or gas pipeline flange area to succumb to the ravages of galvanic corrosion. The application of the threaded zinc cap to the bolt head forms a galvanic cell, thus causing the zinc anode cap to become a sacrificial anode, adding many years of life to the pipeline and in turn saving down time and high repair costs. Northtown zinc caps can provide many years of life to underground pipelines.

We have the Zinc anode cap sizes that you need. Caps are available in sizes from 1/2" up to 2" bolt threads.

Thread Size


1 1/4" x 13/16" high
1 1/4" x 13/16" high
1 1/4" x 13/16" high
1 1/4" x 13/16" high
2 1/4" x 1 1/2 high
1 1/8"
2 1/4" x 1 1/2 high
1 1/4"`
2 1/4" x 1 1/2 high
3" x 2" high
Chemical Composition:
The tolerances for ASTM B418 Type 1 are as follows:

Aluminum 0.1 - 0.5 %
Cadmium 0.025 – 0.07 %
Iron 0.005 % maximum
Lead 0.006 % maximum
Copper 0.005 % maximum
Others (total) 0.10 % maximum
Zinc Remainder
Northtown Company - 5202 Argosy Ave., Huntington Beach, CA 92649 - Phone: 714-897-0700 - Fax: 714-897-0600