Zinc Caps

Seaguard Zinc Caps are designed for prevent corrosion of underground bolts and nuts, valves, fi ttings and mechanical joints on water, gas and oil system. These threaded, hex head caps, when secured to a bolt or stud, become the sacrifi cial anode, corroding, while the remaining metal parts are protected. This corrosion protection continues until the Zinc is consumed.

How Seaguard Zinc Caps work?

Corrosion is an electro-chemical process in which metal parts form a galvanic cell when they are in contact with dissimilar moisture. Using the common battery as an example, moisture becomes the electrolyte while the different metals in the system (such as bolts, nuts, fi ttings etc.) become the positive and negative ends of the battery. The “more negative” component loses material through corrosion while protecting the “positive” component, which becomes shielded. Zinc being much more negative than most other materials, the protected component is essentially immune to corrosion as long as there is Zinc remaining to consume. Seaguard Zinc Caps offer protection for other system components made of steel, cast iron, ductile iron, brass and copper (as shown in the Galvanic Series Chart below). The quantity of Zinc Anode Caps used determines the service life of the protected component.

Large Zinc Caps - 6 oz.
Part IDThread SizeWrench Size
SGZCM20M20 x 2.51-1/2"
SGZCM24M24 - 3.01-1/2"
Large Zinc Caps - 6 oz.
Part IDThread SizeWrench Size
SGZC625S5/8-11 UNC1"
SGZCM16SM16 x 2.01"
SGZCM20SM20 - 2.51"
Practical Galvanic Series
Commercially Pure Magnesium-1.75
Aluminum Alloy (5% zinc)-1.05
Commercially Pure Aluminum-0.8
Mild Steel (clean and shiny)-0.5 to -0.8
Mild Steel (rusted)-0.2 to -0.5
Cast Iron (not graphitized)-0.5
Mild Steel in Concrete-0.2
Copper, Brass, Bronze-0.2
High Silicon Cast Iron-0.2
Voltages are typical in neutral soils and water, measured with respect to copper sulfate reference electrode.

The weight in the tables are nominal weight, the actual weight are different due to different tread size. Other sizes are available on request. Seaguard Zinc Caps are made from special high grade (SHG) zinc conforms to ASTM B418 standard, Type II.

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