If you’ve ever spent time putting together a fence, a patio set, or a backyard deck, you know small parts make all the difference. I’m a lock washers supplier, and let me tell you—one question I get all the time is whether these little metal rings hold up outdoors. The short answer? It depends. But let’s cut through the confusion and break down what actually works when you’re dealing with rain, snow, UV rays, and all that outdoor chaos.
First, let’s remember what a lock washer does. At its core, it’s a tiny, spring-like metal ring (usually split into two tabs) that creates friction between a bolt and a surface. When you tighten a bolt, the washer compresses, and that friction stops the bolt from loosening over time—super important for things that move or get jostled, like a gate hinge or a playground swing. But outdoors, that “stop from loosening” part doesn’t matter if the washer itself rusts, corrodes, or falls apart after a few months.
Let’s start with the big ones: the most common types of lock washers, and how they hold up in the elements. If you ask most people, they’ll mention stainless steel right away, and for good reason. Stainless steel lock washers have chromium in them, which forms a thin, protective layer on the metal that stops rust from setting in—even when it’s exposed to moisture. I’ve had customers tell me they used our stainless steel lock washer on a garden arbor that’s been outside for three years, and it’s still working like new. No rust, no loosening, no issues. But wait—there are different grades of stainless steel. 304 grade is the most common for outdoor use; 316 is even better for coastal areas, since it resists saltwater corrosion way more. If you’re in a place with harsh winters, road salt, or near the ocean, 316 is worth the extra cost. I always tell customers not to skimp on that if their project’s near the beach or on a salted driveway.
Then there’s zinc plated lock washers—these are the budget option people often ask about. Zinc plating is basically a thin layer of metal that acts as a barrier between the steel washer and the elements. It works okay for mild outdoor use, like a shed door that’s mostly under cover. But here’s the catch: that zinc layer can scratch or wear off over time, especially if it’s exposed to constant rain or scrubbing from dirt. Once the zinc is gone, the steel underneath starts rusting, and that’s when the washer fails. I’ve seen customers who used zinc plated lock washers on a fence post in a rainy climate—by the next spring, half of them had rusted through, and the fence posts were loose. So zinc is fine for low-exposure areas, but not for full-on outdoor projects that get wet all the time.
Now, let’s get into the factors that actually make lock washers work (or not) outdoors, because it’s not just the material. First, UV rays. A lot of people forget that sunlight breaks down metal? Wait, no—wait, metal doesn’t break down from UV, but the things around it do. Wait, actually, UV rays can degrade paint or other coatings, but for lock washers, the bigger issue is temperature fluctuations. If you’re in a place where it gets really hot in the summer and really cold in the winter, metal expands and contracts. Lock washers have to handle that movement—if the material is brittle, it might crack over time. Stainless steel is more flexible, so it handles expansion and contraction better than zinc plated, which can get brittle when it’s cold. That’s another reason I push stainless steel over zinc for places with extreme temps.
Then there’s salt and chemicals. If you live near the coast, salt air is a killer for unprotected metal. Even a “little bit of salt” can cause galvanic corrosion if the washer is touching a different metal, like aluminum or brass. Stainless steel (especially 316) is resistant to that, but zinc plated? Not so much. I had a customer in Florida reach out last year—he’d used zinc plated lock washers on his boat dock, and after six months, they were completely corroded, and the cleats he’d attached were loose. Switched to our 316 stainless steel ones, and he’s had no issues since. Chemicals like fertilizer, pool chemicals, or road salt in the winter also eat away at metal fast—so again, stainless steel is the way to go there.
Another thing people don’t talk about: installation. Even the best lock washer will fail if you don’t install it right. A lot of folks just plop the washer under the bolt head and call it a day, but if the surface is rough or uneven, the washer can’t create proper friction. For outdoor use, make sure the surface is clean and flat before you tighten the bolt. Also, don’t over-tighten—you can crush the lock washer so it doesn’t have any spring left, which means it can’t stop the bolt from loosening. Under-tightening is bad too, because the washer won’t make enough contact. I always tell customers: tighten until the washer is compressed, then give it an extra quarter turn— that’s the sweet spot for most outdoor projects.
Wait, but are there any lock washers that I’d warn against for outdoor use? Absolutely. Plain steel lock washers (no plating, no stainless) are a hard no. They’ll rust within months, if not weeks, when exposed to water. I’ve had customers bring me parts that they bought at a big box store—$2 for a pack of 100 plain steel lock washers—and they were so rusty when they pulled them out of the package that they could barely pull them apart. Don’t waste your money on those for outdoor stuff. Also, some cheaper stainless steel grades (like 201) don’t have enough chromium, so they rust when exposed to salt or chemicals. That’s why it’s important to buy from a reputable supplier—we only sell 304 and 316 stainless steel, so you know you’re getting the real deal.
Let’s talk about real-world examples, since that’s what matters most. Last year, I worked with a customer who was building a backyard playground for his kids. He wanted parts that would last, no rust, no loose bolts. We recommended our stainless steel lock washer (/washers/lock-washers/stainless-steel-lock-washer.html) for every bolt on the swing set, the slide supports, and the ladder rungs. A few months ago, he sent me a photo—they’d had a huge rainstorm, then a cold snap, and the playground was still perfect. No loose bolts, no rusty washers. Another customer was putting up a privacy fence in a area that’s not too rainy, just occasional drizzles. He went with our zinc plated lock washer (/washers/lock-washers/zinc-plated-lock-washer.html) for the gate hinges and the fence panels. He’s had it up for a year, and it’s holding up great—no issues, even though it’s exposed to the elements. That’s the key: matching the washer to the job.
Now, let’s wrap this up with what you should actually do if you’re working on an outdoor project. First, assess your environment: is it rainy, coastal, snowy with road salt, or just mild and dry? If it’s coastal, or gets a lot of rain or salt, go with 316 stainless steel lock washers. If it’s just a shed or a gate under a covered porch, zinc plated is a budget-friendly option. Whatever you do, skip the plain steel ones—they’re not worth the hassle. And don’t forget proper installation: clean the surface, get the tightness right, and make sure the washer is sitting flat.
If you’re not sure which washer is right for your project, that’s what we’re here for. I’m a lock washers supplier, not just someone selling parts— I’ve seen first-hand what works outdoors and what doesn’t. We can chat about your specific project, the climate you’re in, and help you pick the right lock washers so your project stays solid for years. Whether you’re building a deck, a fence, a playground, or a dock, we’ve got the parts you need.
References
- Materials Properties Council. (2019). Corrosion Resistance of Stainless Steels in Outdoor Environments. Retrieved from industry materials research database
- American Society of Mechanical Engineers. (2021). Design Guidelines for Lock Washers in Outdoor Structural Applications. ASME B18.21.1 Standard Supplement
- National Association of Home Builders. (2020). Outdoor Hardware Selection Guide for Residential Construction. NABH Residential Building Journal