Bronze Screws and Why They're Used on Boats
Bronze has been used to screw together boats since the first threaded bolts were made in the 15th century, and going even further back to the bronze age the Romans would use bronze rivets to hold together parts on their large ocean going ships. Bronze has long been known to be a corrosion resistant material that is perfectly suited for a seagoing vessel, and that still hasn't changed today.
But WHY are bronze fasteners used on boats?
We touched on it, but the reason is primarily for corrosion resistance. A good quality silicon bronze wood screw resists corrosion in highly corrosive environments such as in and around the salt water present on boats. Even in fresh water, a bronze screw used on a boat will last much longer than it's stainless steel, galvanized, or other equivalent. Silicon bronze in particular is an ideal material, as the alloy has a very low zinc content which lends to it's durability. Brass screws, or other "bronzes" that are actually a form of brass shouldn't be used on a boat in areas that are going to come in constant contact with seawater. The zinc in brass will quickly corrode and disappear, leaving you with a honeycombed, brittle fastener. Likewise, stainless steel is subject to crevice corrosion, and we all know that regular steel or iron is subject to rust.
Bronze is also a relatively hard but malleable alloy when it comes to corrosion resistant materials. Sure, copper is also a great material when it comes to corrosion resistance and many boats are fastened with copper rivets, but a copper wood screw or bolt would simply be too soft to drive. The silicon content of silicon bronze is added to the alloy to harden it and make it usable as a threaded fastener. Combine the hardness for usability, with the relative softness vs. steel alloys and you get a fastener that is hard enough to drive, but still isn't brittle and is therefore resistant to cracking. Your bronze wood screws will drive easily, and will stretch before cracking when worked.
Don't confuse brass with bronze! Numerous customers call and ask for brass screws simply because they are unsure of the difference, not because they actually want brass. Brass has a 30% or more zinc content, and a good quality silicon bronze has less than 2%. Have a look at a galvanic series chart and you can see that zinc is very low on the chart indicating it will be the first material to corrode and fizz away when subjected to a corrosive environment. That means the boat you worked hard on building or restoring will have compromised fasteners holding it together.
No doubt, brass screws have their place on the interior of a boat for aesthetic purposes, and stainless steel screws have their place in areas above the waterline. However below the waterline, and especially on a wooden boat, silicon bronze screws, nuts, and bolts, are the tried and true, time tested, ideal fastener for the job.
We have all the bronze boat screws you could need!
They're hard-to-find, be we are on of the nation's largest suppliers of bronze wood screws for use on your classic or new-build boat. Fair Wind Fasteners regularly supplies some of the nations finest boat builders, and they keep coming back to us when they see that the quality is different from what is normally available on the market these days. Not only is the brand becoming well known in the industry of professional boatbuilding, you can hear some testimonials for yourself as we were recently featured in videos such as here and here.
Check out our selection of top quality silicon bronze wood screws by clicking here.