Aluminum Boats And Treated Wood: Safe Or Not?

Pressure-treated wood and aluminum are a very bad combination. The most common types of pressure-treated wood contain copper, which corrodes softer metals like aluminum when it comes into contact with them. While there may be no immediate reaction, water causes the chemicals in the treated wood to leak out, allowing the copper to eat holes in your aluminum boat.

Pressure-treated wood contains copper, which corrodes aluminium

Pressure-treated wood is wood that has been treated with chemicals to increase its durability and resistance to rot and pests. It is commonly used in outdoor construction, such as decks and boat floors. However, when considering using pressure-treated wood in an aluminum boat, it is essential to be aware of the potential issues caused by the chemicals used in the treatment process.

One of the main chemicals used in pressure-treated wood is copper, which is known to corrode aluminum. When copper comes into contact with softer metals like aluminum, a chemical reaction occurs, leading to corrosion and, eventually, holes in the aluminum. This process is accelerated by the presence of water, which causes the treated wood to leak out the chemicals, allowing the copper to eat away at the aluminum.

The damage caused by pressure-treated wood to aluminum boats can vary depending on several factors, including the type of pressure-treated wood used, the extent of contact between the wood and the aluminum, and the presence of water. In some cases, pitting, indentations, and other early signs of corrosion may be noticed before holes start to form.

To protect an aluminum boat from corrosion caused by pressure-treated wood, it is recommended to use untreated wood or alternative materials such as aluminum sheets or exterior plywood sealed with a non-copper-based sealant. If pressure-treated wood must be used, creating a barrier between the wood and the aluminum, such as plastic bunk slicks or rubber/plastic sheets, is crucial to prevent direct contact and mitigate corrosion.

It is important to note that even with barriers in place, the chemicals in pressure-treated wood can still leach out and attack the aluminum over time. Therefore, the best course of action is to avoid using pressure-treated wood in aluminum boats altogether and opt for alternative materials that are safer and less likely to cause damage.

Water causes treated wood's chemicals to leak out, allowing copper to eat holes in an aluminium boat

Water is a key factor in the corrosion of aluminium by treated wood. While there are different types of pressure-treated wood, the most common types contain copper. This copper content is the main issue when it comes to aluminium boats. Copper corrodes softer metals like aluminium when it comes into contact with them. While there may not be an immediate reaction, water causes the chemicals in the treated wood to leach out, allowing the copper to eat away at the aluminium, creating holes.

This process of chemicals leaking out from treated wood is called leaching. When exposed to the elements, including water, treated wood may release chemicals onto its surface. These chemicals can then be transferred to other materials that come into contact with the wood, such as aluminium. Leaching is influenced by several factors, including the type of treatment applied to the wood, the size and shape of the wood, the type of soil in contact with the wood, and water movement.

The metals used in treated wood, such as copper and arsenic, cannot be broken down. However, they can change their chemical form through a process called speciation. Environmental factors like pH, temperature, soil moisture, and soil type can impact whether and how speciation occurs. The final chemical form can affect its behaviour and toxicity. For example, certain forms of arsenic are more likely to contaminate water.

To prevent the corrosion of an aluminium boat by treated wood, it is recommended to simply use untreated wood or alternative materials like aluminium sheets. If treated wood must be used, creating a barrier between the treated wood and the aluminium is essential. This barrier must be durable and not wear off over time, as direct contact between the two materials will result in corrosion.

In summary, water plays a crucial role in allowing the chemicals in treated wood, particularly copper, to come into contact with and corrode aluminium. This process of leaching can lead to the formation of holes in an aluminium boat. Therefore, it is important to take preventative measures, such as using untreated wood or creating effective barriers, to protect aluminium boats from corrosion.

Pitting, indentations, and corrosion are early warning signs of damage

Pitting corrosion is a localized form of corrosion that results in small pits or holes in the aluminum surface. It occurs when the protective coating on the aluminum is damaged, allowing water or corrosive solutions to attack the metal. The presence of chloride ions, commonly found in saltwater, can further accelerate this process by breaking down the passive oxide layer on the aluminum.

To prevent pitting corrosion, it is crucial to avoid direct contact between treated wood and aluminum. This can be achieved by using untreated wood, sealing the wood with a suitable coating, or creating a barrier between the two materials. Regular cleaning and maintenance of the aluminum surface can also help to identify and address early signs of corrosion.

Additionally, stagnant water should be avoided by properly inclining the boat's surface and providing adequate drainage. The ventilation of enclosed spaces can also reduce the risk of condensation and corrosion.

In summary, pitting, indentations, and corrosion are early warning signs that the treated wood is damaging your aluminum boat. Taking proactive measures, such as using untreated wood, proper sealing, and regular maintenance, can help prevent costly repairs and ensure the longevity of your boat.

To protect an aluminium boat, use untreated wood or aluminium sheets

If you want to protect your aluminium boat from corrosion, it's best to avoid using pressure-treated wood. This is because most types of pressure-treated wood contain copper, which reacts with softer metals like aluminium when it comes into contact with them, causing corrosion.

So, what can you use instead? Well, you could use untreated wood. Simply use regular exterior plywood and seal it yourself with something that doesn't contain copper to make it watertight. However, keep in mind that wood will eventually rot, so you may want to consider using aluminium sheets instead. They're lightweight and won't rot like wood.

If you absolutely must use treated wood or already have it installed, you can create a barrier between the wood and the aluminium to prevent direct contact. This could be done with plastic or rubber sheets, or by coating the wood with something like polyurethane. Just be aware that this may require extra work and money, and even then, it may not be enough to completely prevent corrosion.

In summary, to protect your aluminium boat, your best options are to use untreated wood and seal it properly, or to use aluminium sheets.

If you must use treated wood, create a barrier between the treated wood and aluminium

If you must use treated wood, it is important to create a barrier between the treated wood and the aluminium to prevent corrosion. The barrier must be effective and long-lasting, as corrosion will occur if the copper in the treated wood comes into contact with the aluminium.

One way to create a barrier is to use a product like plastic bunk slicks to cover your trailer bunks and prevent direct contact between the treated wood and aluminium. You could also use thin sheets of plastic or rubber between the wood and aluminium. Additionally, consider coating or covering the bolts used to secure the wood, as they can also corrode over time if they are in direct contact with treated wood.

It is worth noting that even with a barrier, there is still a risk of corrosion. Therefore, it is recommended to avoid using treated wood on aluminium boats whenever possible. Untreated wood that has been sealed with a suitable coating, such as polyurethane, epoxy, or fiberglass resin, is a safer alternative.

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