No. Blog over.
Just kidding. Let’s really dive in this week because this is not as obvious as some make it to be. Its gonna get technical, so get out your protractor and your TI-85.
When researching hardware for marine equipment, you will find many impassioned opinions. The quick and easy answer you might find (especially from sellers of stainless steel dock hardware), is that stainless steel is rust resistant, strong, and zinc is neither. So why wouldn’t you use stainless steel on your dock for all nuts & bolts needs? As with many quick and easy, quotable opinions, there is more nuance to it than that.
When you hear that stainless steel is largely rust free, that doesn’t take into account galvanic action against two dissimilar metals (steel against the aluminum of your dock). Aluminum and stainless steel combine to cause galvanic corrosion, since it is an anode and a cathode coming into contact with one another. Aluminum is the weaker of the two in this rust battle. Stainless steel hardware is notorious for binding up and making it impossible to remove or replace hardware on an aluminum surface.
The word “corrosion” there, you guessed correctly, means rust. Rust not just for the stainless steel but the aluminum of your dock as well. And the constant exposure to water and the elements only exacerbates galvanic corrosion. Salt water, does so even more. This is not just an aesetic issue – its also a structural concern. Rust looks horrible and also can weaken the metal.
So what metal is more susceptible to breaking under weak conditions – steel or aluminum? You guessed it! Aluminum will fail every time. With aluminum docks this is a more costly loss. A failing frame is certainly worse than a failing bolt.
Still want stainless hardware on your dock? If you insisted on adding stainless steel to your aluminum dock, say in salt water conditions, you will need to separate the aluminum from your steel by adding a custom plastic washer, rubberized undercoating, or electrochemical galvanizing spray. Salt water can be treacherous to your marine hardware, even still.
Now when you read about stainless steel dock hardware versus zinc plated metal, you will hear that zinc isn’t rust-resistant like stainless steel is, and not as strong. Standard zinc plating will rust at a pretty fast rate, so this is a bad coating for your dock hardware. Truth! However, there is higher grade zinc-coating process, which IS rust-resistant!. Jack Docks uses Grade-8 Zinc-Plated hardware, which takes a gold tone and offers terrific rust protection, but it also maxes out its tensile strength at 150,000 PSI. This is the exact same strength of stainless steel! These are often used for armored vehicles and vehicle suspensions, due to their strength and ability to withstand outdoor conditions.
This is why experts will use Grade-8 zinc-plated metal when combining with aluminum materials, especially when you add water to the mix. You don’t want rust anywhere, but better your hardware than the frame and structures supporting you as you walk overtop of the dock. These Grade-8 Zinc-Plated nuts are serrated with no need for lock washers and resist rust like the best corrosion resistant hardware.
We encourage you to do an easy web-search for ‘stainless steel with aluminum’ and see for yourself. Don’t take our word for it! To shop online with some peace of mind that your dock will last, check out our SHOP!