Commercial Zinc or Aluminum Boat Hull Anodes (Zincs)
At Purity Alloys we manufacture a wide range of Sacrificial Anodes for shipyards, distributors & marinas from 0.5 lbs to 600 lbs providing cathodic corrosion protection for the marine environment. Our facility is equipped to produce a variety of anodes, from standard designs to custom solutions. Whether you need heater treater anodes, cathodic protection for pipelines, or bespoke anodes for marine applications, we've got you covered.
Purity Casting Alloys has been manufacturing Sacrificial Aluminum and Zinc Anodes since 1992. Our success in the Anode business is due to our commitment to product quality, product availability, and custom Anode sizes.
With our onsite spectrographic analysis you can be assured of alloy consistency from Anode to Anode.
Purity's Aluminum and Zinc Anodes are manufactured with a wide variety of core materials to meet your specific application requirements. All Aluminum Anodes correspond to MIL-A-24779 and Zinc Anodes meet MIL-A-18001K.
Anodes (Zincs) are available with a variety of cores:
- Steel or Aluminum Weld-on straps
- Steel or Aluminum Bolt-on inserts
- Steel cable inserts; Stainless Steel Nuts or Bolts
- Threaded Rods
All Aluminum and Zinc Anodes meet US military specifications MIL-A-18001 & MIL-A-24779 also covered by ASTM-B-418-73, Type 1. Only graphite ladles & crucibles used - ensuring low iron contamination.
Many people call Sacrificial Anodes "Zincs" because Aluminum is not used for various reasons - cost primarily. Aluminum Anodes are lighter and generally last almost twice as long as Zinc Anodes. As the price of Zinc goes up, the cost per pound ratio makes Aluminum more cost effective as an Anode material.
Whether it is for fishing boats, ocean going vessels, or crab traps we can provide low cost cathodic corrosion protection with Anodes. Custom Anodes are our specialty so please contact us with your requirements.
The Advantages of Aluminum Anodes
Many manufacturers and boaters prefer aluminum anodes over zinc or magnesium for several reasons.
- Aluminum has become more affordable in recent years, making it a popular choice for installing sacrificial anodes on vessels, engines, and other equipment.
- • Aluminum anodes protect effectively in saltwater, perform better in upper brackish water, and decently in freshwater, but they tend to develop an oxide coating (passivation) faster than zinc. Regular cleaning prevents this, ensuring aluminum anodes remain effective.
- • EPA reports indicate that magnesium and aluminum anodes are more environmentally friendly than zinc, though the environmental impact of zinc is minimal.
The Advantages of Zinc Anodes
Zinc is the ideal sacrificial anode when a vessel is docked or anchored in seawater for extended periods.
- Unlike other metals, zinc is better at shedding film buildup, continuously exposing fresh zinc to the water and keeping the anode electrochemically active. Aluminum anodes, in contrast, can develop a crust that passivates the anode, making it less effective.
- The longer a vessel sits idle, the greater the risk of anode passivation. However, when the vessel is moving, the water flow helps clean off the oxide layer and reactivate the anode, regardless of the metal type.
- For vessels that are regularly active in saltwater, both zinc and aluminum anodes work well. But if a boat remains stationary for extended periods in saltwater, zinc anodes are the better choice.