3651536326

Becoming Bold as Brass: How to Deal with Brass Fittings on a Boat

Brass—an alloy of copper—is a metal that is almost synonymous with the sea. High quality brass fittings offer excellent resistance to corrosion that makes them a natural first choice for many seafaring applications, from clocks and lamps to joinerwork trim and electrical components. However, as you may have deduced from the uses listed, brass is best used onboard a boat and not in raw-water applications. Steve D’Antonio explains why, in his article for Cruising World:

While brass works well in above-the-waterline applications, it’s certain to fail when put to work in situations that leave it constantly exposed to seawater. Because of its high zinc content, brass suffers from a peculiar type of corrosion known as dezincification; when this happens, the zinc sacrificially corrodes from the alloy, leaving behind a porous, weak copper structure that deceptively retains its shape yet is devoid of most of its original rigidity. Such fittings are often pinkish, and they can often be easily broken with minimal effort.

Don’t be fooled by such alloys as admiralty brass and naval bronze, which sound like they should be corrosion resistant. Due to their relatively high zinc content, these are indeed brasses, and they shouldn’t be used in plumbing applications below the waterline or involving seawater.

So there you have it: Never use brass for any purpose where it comes in contact with seawater. This includes plumbing associated with seacocks, stuffing boxes, raw-water strainers, and air-conditioning and sanitation systems. According to experts, brass is ill-suited for any use where it’s required to convey, stem or direct the flow of seawater, regardless of whether you use it above or below the waterline.

Bronze

Seawater can be handled successfully with bronze. Bronze is a copper alloy just like brass, but it’s different in the sense in that it doesn’t contain any appreciable amount of zinc, making it less susceptible to dezincification. Bronze, however, is often more expensive than brass, but the additional cost is worth it if you want a material that handles seawater well.

Conclusion

When it comes to different seafaring applications, you need to know what materials are suitable for which function. Brass, bronze, and similar alloys look the same, so a deeper knowledge of their characteristics and underlying differences can help you avoid a catastrophic failure. Quality brass and bronze pipe fittings are available from reputable manufacturers like Gruner Brass Fittings Corp.

(Article information and image from Down to Brass Tacks, Cruising World, July 19, 2013)