The easiest way to prevent rust on screws is to shield them completely from moisture, be it through selective placement or protective coatings and sealants. Purchasing specially formulated, rust resistant or rustproof screws is usually helpful, as well. Many of the most effective rust prevention tools must be purchased commercially at hardware or home improvement stores. Depending on the types of screws at issue, a number of home remedies may also work.
Rust is the result of a chemical reaction between certain metal compounds and water vapor. The presence of certain oxidizing agents, particularly salt, tends to increase a metal’s propensity to rust. Screws that are used outdoors or in moist environments like bathrooms or swimming pools are particularly prone to rusting. The best way to shield screws from the moisture latent in their surroundings is by covering them with some form of a protective sealant.
Commercial anti-rust solutions often come in the form of liquid lacquers or sprays. Most of these contain zinc, which is well known to resist corrosion, as well as graphite powder to aid adhesion. In high-moisture settings, it is important to coat the entire screw before using it. This can make construction somewhat difficult, as treated screws are bound to be slippery. Simply coating the heads and the majority of the neck during installation is usually easier, and lends similar results.
Many hardware stores sell specially-formulated screws made of alloys designed to resist rust, which make for more of a foolproof solution. Screws made of or coated with zinc, tin, or chrome only rarely succumb to corrosion, and are of particular use in industrial settings. Topical coatings are not usually required to prevent rusted screws, though settings should nonetheless be regularly checked for signs of water penetration.
Specialized screws can be costly and are not always the best choice for more casual use. In and around the home, standard screws are usually a more economical option. Stainless steel varieties tend to be more rust resistant than basic metal options, but even these cannot guarantee against rusted screws. Regularly checking and sealing screws is usually the best option for more budget-conscious property owners.
Painting over screws is often one of the easiest means of rust prevention in simple construction settings. While paint is not usually a foolproof way to prevent rusted screws, it can work as a temporary barrier. Screws that are painted to match their surroundings often blend more seamlessly, as well.
Treatments must usually be checked each year to be sure that all metal areas remain covered. For outdoor screws, this is often best accomplished in the summer, when things are driest. Quick touch-ups are often all that is required to keep rusted screws at bay for another season.
Nail varnish is another simple solution, particularly for Small screws in bathrooms and kitchens. Clear nail enamel provides the same moisture-sealing benefits as paint, but in a less obtrusive and often barely noticeable way. Wax, mineral oil, and more general around-the-house sealants work similarly. Do-it-yourself fixes are not always appropriate ways to prevent rusted screws in large-scale building projects or in more industrialized settings, but are often the easiest solutions for screws here and there around the house.