Fasteners In Salt Water Environments
One of the biggest complaints we hear about are fasteners rusting prematurely. The first question we are likely to ask is “Are you within 20 miles of a salt water environment?”
Surprisingly, an overwhelming amount of customers say yes. It is commonly understood that metal rusts and that it rusts worse in corrosive environments. It is not commonly understood that those environments spread beyond what the eye can see, however, this should be one of the bigger factors taken into consideration when buying fasteners.
Stainless steel is a prime example of this. Almost anyone you talk to can tell you stainless steel is corrosion resistant, but did you know that grade 410 stainless steel is less corrosion resistant because it is heat-treated to be harder? or that grade 304 stainless is not suited for highly corrosive environments?
In fasteners, the material and sometimes even the grade matter when it comes to choosing the right fastener for your installations. There are several materials that do extremely well in salt-water environments, some that kind of work and some that are almost guaranteed to fail.
What You Should Use
There are generally a few materials that work extremely well in salt-water environments. Depending on your needs you should aim to choose from the following:
- Grade 316 Stainless Steel
- Silicon Bronze
These materials (or specific grades) are ideal for salt-water environments because they can resist the corrosive effects that salt-water very well.
Another option to try is HDG (Hot Dip Galvanized) fasteners. HDG is a form of zinc coating that will protect the fastener from harm and is usually a cheaper option but is not a perfect solution.
HDG fasteners can handle well in certain salt-water environments but results can vary depending on if they are submerged, water temperature and air temperature. Due to these factors, we do not recommend it as it will likely not perform as well as the materials listed above.
Although 316 stainless steel and aluminum are both listed as good materials to use in corrosion resistant environments, you also do not want to mix the two. If you do, the process of galvanic corrosion is more than likely to occur, resulting in a significantly shortened lifespan for your fasteners.