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Do Zinc Screws Rust or Corrode? Can They Be Used Outside?

For a long time, zinc screws have been a household and dependable name. It was simple and inexpensive to electroplate any metal with zinc. There are various alternatives to zinc screws available now, some of which are rather pricey. 

The dilemma is whether you should use zinc screws or new ones. Let’s all explore.

Do zinc screws rust or corrode?

Any metal screw that is exposed to air and moisture can rust or corrode over time. Zinc screws, on the other hand, will be handier than other metal screws. Zinc’s oxidation process is slower, which means it will remain intact and will not corrode for a long time.

Rust and corrosion of screws have been a headache for a long time and people have been trying to find an ideal solution for this issue. Different types of metal screws have been used but nothing can give a long-lasting effect. 

Metal screws became rusty in a moist atmosphere and corroded over time, so extra precautions need to be applied to make them last longer. 

Electrocoating was the most well-known and easy method for making the metal resistant to oxidation or rust and for the coating material, zinc is the perfect fit. 

Zinc coated screws are known for their longevity and they are the cheapest electro-coated screws available in the market. Zinc-coated screws will last five to ten times longer than any ordinary screws. 

The air and moisture in the air always try to react with metal components but when it’s zinc-coated the oxidation process gets rejected and even in harsh conditions it will rarely take place. 

Zinc’s ability to resist oxidation and slow down any corrode even in the worst-case condition is remarkable. There are several versions of zinc-coated screws available in the market, the yellow zinc plated screws are one of the best among them. 

The zinc coating along with the yellow dye not only brings out the aesthetic beauty but also gives extra protection against rust.

Can zinc screws be used outside?

Different atmospheric conditions affect metal differently. Zinc screws may last longer than other metal screws but they won’t last in harsh conditions. Zinc will rapidly corrode in presence of salt in the atmosphere or in direct contact with salt water. Zinc screws are not ideal for outside uses.

There are several factors at play when it comes to using a zinc screw outdoors. Metal has a high tendency to react with moisture and air. 

An unprotected metal screw will go through the oxidation process, it creates a red-brown coating on the outer layer and starts to corrode over time. The zinc coating can resist this oxidation process but it will give up in presence of salt and mineral-rich air. 

Zinc-coated screws are not ideal for people living near the sea, the zinc coating of the screws will wear out pretty quickly in such an atmosphere. 

Nowadays the frequent acid rain, forest fire, storms all have horribly affected the air condition, and relying on zinc coating may not be a wise choice. 

It is hard to change rusty screws or replace them with a perfect size, you may find a perfect replacement and change it but it’s possible for the screws that are visible, easy to reach. 

If the screw is placed on the inner parts, hard to reach places then you are up for a great deal of trouble. Zinc coated screws may be affordable and have gained a name for themselves but it’s not suitable for outdoor use anymore. 

How long will zinc screws last outside?

A zinc screw may not last that long while used in an outside project. Zinc can certainly slow down the rust buildup process but it will only last a week before the first red spots start to build

An ordinary metal screw may be covered in rust in two or three days so zinc is somewhat reliable but it’s not suitable for outside use. 

In lab testing done in a controlled environment and constant motorization, it was found that the zinc can resist the salty moist air for up to 200 hours before any signs of oxidation or rust buildup. 

Do stainless steel screws rust? Is zinc plated better than stainless steel?

Stainless steel screws are known for their strength, durability, and long-lasting service period. When it comes to rust, it’s pretty rare to find a rusty stainless steel screw

Looking at the building components of stainless steel, being an iron alloy along with a significant amount of chromium makes it pretty well resistant to oxidation reaction. 

In your showers, basin, kitchen you would find stainless steel pipe, tap, screw and they will last for a long time even after being in the constant presence of water. 

Stainless steel screws are better than zinc-plated screws. However, ordinary zinc-coated screws are far cheaper than stainless screws. 

But it’s not zinc vs stainless steel anymore, manufacturers have been using zinc to coat a protective layer in the stainless screws, making them even more resistant to rust buildup.

What are the outdoor screws that won’t rust?

No matter what screw you use, if the condition isn’t suitable they will not last for a long time and will get rusty. Generally, people living near the coastal area or in a place with heavy rain and snowfall always have a bitter experience even with the best screws. 

Here are some options that may not disappoint you. 

Stainless galvanized screw:

Stainless screws haven’t been able to perform up to the mark when it comes to being rust-resistant. So the galvanization process was applied which made it much more reliable. 

However, only stainless steel with high nickel content is suitable for galvanization so it’s going to cost you a significant amount of money to buy them.

Galvanized screw:

In most cases, the screws are electro-coated, these galvanized screws may not last very long but screws that are mechanically galvanized perform much better in both normal and harsh conditions. 

In electro coating and mechanical galvanizing, zinc is used but the electro-coated screws don’t perform up to the mark when it comes to outside uses. 

Mechanical galvanized zinc screw may cost much more than the electro-coated zinc screw but you can rest assured about the quality and longevity.

Deck screw:

Specifically designed for use in deck and it’s highly rust-resistant. You can use these screws for any kind of project, it will surely last longer even in the marine environment.

How to prevent outdoor screws from rusting?

The following tips might help you to prevent outdoor screws from rusting –

Use the right screw not the cheap one:

Screw helps the structure to keep its integrity and the quality of the screw sometimes can remarkably affect the overall longevity of the structure. 

You may have worked hard on a project, even used the best materials but if you have made the mistake of buying a cheap screw instead of buying the right one then you may have to deal with a rusty screw in a few days. 

Stainless steel screw mechanically galvanized zinc screw may cost you a bit much but they will certainly provide your money’s worth. These screws will resist rust buildup and survive even in the worst situation.

Moisture shield:

if you can’t afford the expensive screws or used expensive screws and the experience is bitter then you can think of something to keep them away from any kind of moisture. 

In the presence of moisture, it will become hard for the metal to stay intact, it will surely participate in an oxidation reaction and corrode. 

Applying a moisture shield is easy to do if you are doing a wooden project, but for other situations, you may need to use special sealing components.

Zinc plated vs galvanized vs stainless steel screws for outdoor use:

Let’s walk through this section thoroughly to find out which screws will be more suitable for outdoor use –

Marine environment:

In marine environments, it’s hard for all of them to stay rust-free, so you can eliminate the weakest zinc plated screw. Stainless screws will last significantly longer than electro-coated zinc screws. 

But due to being in contact with salty air and water for a long duration, a rust buildup may be visible. Mechanical Galvanized zinc screw will outrun all of them.

Ideal conditions:

If you live in a place with no acid rain or heavy rainfall then the stainless screws will be your best bet. Galvanized screws will also perform well. 

However, a zinc-plated screw isn’t made for outside use so you can avoid it or use a proper moisture shield.

Final thoughts

Zinc’s oxidation reaction or corrosion process is significantly slower, thus it will last longer. However, metal screws will rust over time if exposed to air and moisture, zinc screws are not an exception. But compared to other metals, zinc screws are more convenient for outside use.