Best Fasteners For Aluminum Boats: A Comprehensive Guide

When it comes to fastening aluminium boats, the type of fastener you choose is crucial to prevent corrosion, especially in saltwater environments. While stainless steel fasteners are commonly used and provide strong fastening, they can cause galvanic corrosion when in contact with aluminium. This is due to the dissimilar metals creating a magnetic resistance, which, in the presence of dissolved oxygen, leads to the breakdown of the weaker metal (in this case, aluminium). To mitigate this issue, it is recommended to use aluminium fasteners or, if additional strength is required, to isolate the dissimilar metals using nylon washers, high-density plastic, or a sealant like Tef-Gel. Another option is to use zinc-coated steel screws, as zinc is less corrosion-resistant than aluminium and will sacrifice itself to protect the boat. For saltwater applications, 316 or 316L stainless steel is recommended over 304 stainless steel, as it is a better alloy for the job.

Stainless steel is a good option for fasteners on an aluminium boat

Stainless steel is a strong and robust material, and its strength means that it is unlikely to loosen over time. It is also easy to tap into harder materials. Stainless steel is completely resistant to corrosion, so it will not rust, even in saltwater. This makes it a good choice for boats that are kept in the ocean.

There are different grades of stainless steel, and for submerged components, it is recommended to use steel with at least 6% Molybdenum in the alloy. Austenitic stainless steel grades are suitable for deck components.

When using stainless steel with aluminium, it is important to be aware that galvanic corrosion can occur when the two metals come into contact with an electrolyte, such as saltwater. To avoid this, it is recommended to use a galvanic insulator between the two materials. Products such as Tef-Gel can be applied to the threads of the fasteners to prevent corrosion and act as an anti-seizing agent.

Tef-Gel can be used to prevent corrosion between stainless steel and aluminium

When it comes to fastening aluminium boats, stainless steel is the best choice. However, using stainless steel fasteners on an aluminium boat can lead to corrosion. This is due to the galvanic reaction between the two dissimilar metals, which is exacerbated in saltwater environments.

Tef-Gel is a product that can be used to prevent corrosion between stainless steel and aluminium. Tef-Gel is a PTFE-based paste that acts as a watertight lubricant and sealant. It is applied to the threads of bolts and screws, as well as the holes they will be inserted into, creating a layer of solid PTFE within the thread interface. This layer acts as a friction barrier, preventing direct contact between the two metals and impeding the galvanic reaction that causes corrosion.

Tef-Gel is commonly used in marine applications, such as on sailboat masts, and is effective in preventing corrosion during long-term submersion. It is important to note that Tef-Gel does not electrically insulate hardware or electrical connections. Additionally, it should not be used with plastic as it can cause embrittlement and failure.

When using Tef-Gel, it is recommended to be generous with the amount used and to avoid exposing it to temperatures above 450°F (230°C). It is also important to clean any tools or surfaces that come into contact with the product with turpentine.

By using Tef-Gel, you can help prevent corrosion between stainless steel fasteners and an aluminium boat, ensuring the longevity of your boat's hardware.

Sacrificial anodes can be used to prevent corrosion

When it comes to aluminium boats, it's important to consider the impact of corrosion on the vessel's key parts. Corrosion can be caused by the effects of saltwater and electrical currents, leading to the degradation of metal components. To address this issue, sacrificial anodes can be used as a protective measure.

Sacrificial anodes, also known as sacrificial blocks, are designed to attract corrosion away from the boat's metal parts. Made from metals such as zinc, aluminium, or magnesium, these anodes are more easily corroded than the metal they protect. By connecting the anode to the metal object, the anode becomes the material that gives up electrons and dissolves, sacrificing itself to preserve the boat's metal components. This process, known as galvanic corrosion, occurs when two metals with different electrical activity levels come into contact with the same conductive liquid, such as seawater.

In the context of aluminium boats, it is recommended to use aluminium or zinc anodes. Aluminium anodes are lightweight, work in both saltwater and brackish waters, and can last up to 50% longer in saltwater. They are also more environmentally friendly than zinc anodes. Zinc anodes, on the other hand, have been traditionally used and work well in saltwater environments. However, zinc is the heaviest option and is more toxic to the environment. It is important to note that anodes should not be painted or mixed with different metals, as this can affect their performance.

To ensure the effectiveness of sacrificial anodes, they should be placed strategically and remain submerged. They can be welded to a metal hull surface or bolted and tied with brackets. Regular inspection and replacement of anodes are crucial, as they wear away over time. By prioritising the maintenance of sacrificial anodes, boat owners can effectively prevent corrosion and extend the lifespan of their aluminium boats.

Nylon washers can be used to prevent contact between metals

When it comes to fastening aluminum boats, the choice of hardware is crucial to prevent corrosion. While stainless steel screws are often used, they can cause corrosion, especially in saltwater environments. To address this issue, nylon washers can be employed as an effective solution.

Nylon washers serve as an insulating barrier between dissimilar metals, such as stainless steel screws and aluminum boat parts. By preventing direct metal-to-metal contact, nylon washers help to minimize the risk of electrolytic corrosion. This type of corrosion occurs when different metals are in direct contact and can significantly reduce the lifespan and functionality of the boat's components.

Nylon washers offer several advantages over metal washers. They are durable, lightweight, and highly resistant to corrosion and surface wear. Additionally, they excel at absorbing noise and shock, contributing to smoother and quieter boat operations. The water-resistant properties of nylon washers also play a crucial role in moisture management, repelling moisture accumulation and protecting the boat's components from corrosion.

When using nylon washers, it is important to ensure proper installation. Applying products like Tef-Gel or grease to the threads of the screws before tightening can further enhance the corrosion-resistant properties of the assembly. Additionally, using "shoulder washers," which are specifically designed to isolate dissimilar materials, can provide additional protection.

By utilizing nylon washers in conjunction with stainless steel screws, boat owners can effectively prevent contact between metals, mitigate corrosion, and ensure the longevity and optimal performance of their aluminum boats.

Aluminium fasteners are another option

Aluminium fasteners are the best option for your boat if you are looking for a strong fastener. While aluminium pop rivets are made with either an aluminium or steel shaft, the aluminium shaft is a better option to prevent corrosion.

If you are looking for a more permanent option, welding the aluminium fasteners to the boat is a great choice. This will ensure that your fasteners will not come loose over time.

When using aluminium fasteners, it is important to apply wax to the threads before tightening. This will prevent the fasteners from seizing up and breaking.

Additionally, when using aluminium fasteners in saltwater, it is recommended to use a product called Tef-Gel to isolate the metals and prevent corrosion. This product is also used by reputable shipbuilders and the US Navy, proving its effectiveness.

By following these recommendations, you can ensure that your aluminium boat is securely fastened with aluminium fasteners that will not corrode or cause any damage to your boat.

Frequently asked questions