Are you thinking about putting new flooring in your aluminum boat? Or perhaps replacing the transom? You might be thinking that pressure treated wood is the best wood to use for this job — after all, the wood is treated to make it last longer, right?
Don’t make that mistake. Turns out, pressure treated wood and aluminum are a very bad combination. Put the two materials together, and you’ll end up with holes in your boat.
What Happens When Pressure Treated Wood Meets Aluminum?
While there are different types of pressure treated wood, the most common types contain copper. That copper content is the big problem — when copper comes into contact with softer metals like aluminum, it corrodes. While you might not see an immediate reaction, water causes those chemicals in the treated wood to leak out, allowing the copper to quite literally eat holes in your aluminum boat.
Before the holes show up, you’ll likely notice pitting, indentations, and other early signs of corrosion. Don’t ignore those signs; they’re only going to get worse over time.
This video gives an up-close look at what happens when someone uses pressure treated wood in an aluminum boat. Whether the wood is used for flooring, the transom, on a trailer, or anywhere else on the boat, it will corrode, causing leaks and requiring a total replacement of the wood before too long — if the boat is even salvageable.
How Do I Protect My Aluminum Boat?
So what can you do to protect your boat from being corroded by the copper in the wood treatment? The easiest solution is simply to use wood that isn’t treated. Save yourself a headache later, and prevent the problem from happening in the first place.
Instead of pressure treated wood, it’s better to use regular exterior plywood that you seal yourself (with something that doesn’t contain copper, of course!) so it’s watertight. Or don’t use wood at all — aluminum sheets, for example, are lightweight, and won’t eventually rot like wood will.
But let’s say you already have pressure treated wood in there, or for some reason you absolutely must use treated wood. Is there any way to keep the copper from getting to the aluminum?
There is, but it may require a little more work and money. You’ll need to create a barrier between the treated wood and the aluminum that won’t eventually wear off. That means even something like paint may not be enough to keep the copper from leaching out and attacking the aluminum. Depending on where the wood is used, you may be able to use a product like plastic bunk slicks to cover your trailer bunks and keep the treated wood and aluminum from touching.
Also consider coating or covering the bolts you use to secure the wood, because if they’re in direct contact with treated wood, they can corrode over time, too. And finally, keep in mind that materials such as carpet will trap moisture on your wood and — treated or not — cause it to rot.
The More You Know
The bottom line is: if you can at all afford to avoid using pressure treated wood on your boat — just don’t use it. And let’s be real, nine times out of ten you can definitely afford to take action now to prevent future damage that would end up being more costly and time-consuming in the long run.
At Marine Tech, we’re committed to helping you catch big problems early on, or avoid them altogether, and to making sure you have the tools you need to fix them yourself.
