Stainless Steel Letters in a Marine Environment [An Architectural Resource] December 11, 2011 Dimensional Sign Letters Resources Stainless Steel Letters Alloy 304 vs. 316 for Marine Environments It has been discussed many times by architects, designers, the military, and for any design project in a marine environment involving metal letters, such as on ships, naval bases, hotels along the coast, and on any project in the islands. We present our recommendations and issues here. What is the difference in material between stainless steel alloy 304 and alloy 316? 316 alloy, also referred to as marine grade, has less carbon and additional nickel content vs 304 alloy. As such it’s resistance to chemicals and environmental wear, and the salt and humidity in marine environments, is higher. It does come with an additional cost of approximately 60%. Why is alloy 316 recommended for a marine environment? You can put 304 alloy stainless steel letters in a marine environment but you should expect to have to clean and buff the sign more frequently to keep it’s appearance. Corrosion will begin to build up, and you should clean it regualrly with a good stainless steel cleaner, however alloy 304 will need to be cleaned much more often than alloy 316, as the corrosion will build up faster. Is there any benefit to stainless steel having a protective clear coat in a marine environment? A clear coat is generally only added to aluminum or brass material because their corrosion resistance is significantly less than stainless steel. However, if a clear coat is subjected to chemicals or a harsh environment such as salt it will begin to break down and chip off. What happens if you do put a clear coat on in a marine environment? Unfortunately the clear coat will break down unevenly. Sections will begin to wear unevenly. That is the major issue. You will actually see chips of the clear coat flaking off. I’m sure you’ve seen this on an old car where the hood or roof has been exposed to extreme weather. At that point if you wanted to finish look okay you’d have to chemically strip the clear coat. But you run the risk of hurting the polished finish when you do this. It’s really a pretty big mess waiting to happen. We highly recommend Stainless Steel Letters which will be exposed in a marine environment, whether polished finish, or satin grained finish, to be alloy 316.