A Brief Guide to Homemade Windshield Water Repellent

Bad weather can make it harder to see through the windshield of your car or truck. While windshield wipers do their best to remove rainwater and snow, downpours and heavy snowfall can overwhelm their ability to keep the car glass clear. The windshield glass can also become dirty because of other factors like deposits left by previous exposure to rain and pollen. Fortunately, applying water repellent to the glass can assist the wipers in clearing the windshield. One of the most popular brands is Rain-X, leading to many people referring to water repellent as Rain-X.

But sometimes, you can’t afford or access commercial windshield water repellent products. Instead of driving in rain or snow while unprotected by rain repellent, you can make an alcohol-based equivalent with ingredients you can find at home. Homemade windshield water repellents offer advantages over their commercial counterparts, making the DIY products more attractive and better suited to your needs.

Homemade Windshield Water Repellent

There are two windshield water repellent solutions that you can make at home. One uses alcohol and vinegar as its active ingredients. The other is an ethanol-alcohol mixture.

Whatever formula you choose, the homemade rain repellent will ensure that water slides off the windshield glass.

Alcohol-Vinegar Windshield Water Repellent

The recipe for homemade alcohol-vinegar-based windshield water repellent requires the following ingredients:

• Two tablespoons of liquid dish soap
• One cup of distilled white vinegar
• Two cups of isopropyl alcohol or rubbing alcohol
• Three quarts of water

Additionally, you can choose to add the following ingredients for convenience:

• 5 to 6 droplets of food coloring, usually blue
• 10 to 20 drops of essential oil

The alcohol-vinegar windshield water repellent will work fine without food coloring. However, the additive will make it easier to identify the rain repellent as a cleaning solution instead of something edible.

Meanwhile, adding essential oil makes the homemade windshield water repellent smell more pleasant. Both alcohol and vinegar have strong smells, which many people don’t like.

As for tools, you’ll need the following:

• Funnel
• Gallon container
• Measuring cup
• Spray bottle

Attach a label on the gallon container that clearly identifies its contents as windshield water repellent. Store it in a location that children can’t reach.

Making Alcohol-Vinegar Rain Repellent

Use the measuring cup to get the right amount of alcohol and vinegar. Pour the two into the gallon container. If you want to include essential oil, food coloring, or both, add them.

The next step is to add water to the mixture, followed by the liquid dish soap. Shake the container with care. Now you have homemade windshield water repellent.

Pour the homemade rain repellent into your car’s washer fluid reservoir. Once you fill the reservoir, keep the remaining windshield water repellent in a safe location out of reach of children.

You can also pour some of the homemade windshield water repellent into a spray bottle. This approach lets you apply the rain repellent on the other car glass.

Ethanol-Alcohol Windshield Water Repellent

If you’re not keen on using vinegar on your car, you can use an ethanol-alcohol-based rain repellent instead. The following are the ingredients you will need to make this water repellent:

• 5 ml of rubbing alcohol
• 86 ml of ethanol
• 9 ml of either castor oil or silicone oil

You will also need the following tools:

• Spray bottle
• Graduated cylinder

Making Ethanol-Alcohol Rain Repellent

Use the graduated cylinder to measure the appropriate amounts of rubbing alcohol, ethanol, and oil. Then pour those ingredients into the spray bottle.

Don’t screw the cap on the spray bottle. Instead, gently shake the bottle to swirl the ingredients together. The bottle will feel warm to the touch because of the mixture.

Let the spray bottle and its contents cool off. Once the bottle no longer feels warm, cover the bottle. You can now apply the homemade rain repellent on your car’s windshield.

Clean and dry the windshield of your car before applying the homemade rain repellent. Spray the solution on the car glass and dry every square inch of the wet surface with a clean and dry cloth.

Congratulations! You’ve successfully applied homemade windshield water repellent to your car. Rainwater and snow should now get repelled from the glass.

What Does Car Windshield Water Repellent Do?

Rain repellent helps water form beads on the surface of the windshield. Water beads slide off the glass more easily. It also works on snow.

Additionally, rain repellent prevents ice formation on the windshield. If ice does form, it’s usually easier to remove.

Windshield water repellents contain various chemicals that work together to clean and protect the windshield. Rain-X, for example, relies on polydimethylsiloxanes as its active component. Polydimethylsiloxanes form a layer on the windshield that provides low surface tension. They repel water, which is a high-surface-tension fluid. Some products have additives that get rid of dead bugs on the windshield.

There are also windshield washer fluids out there that have additives to help remove bugs.

–Anthony Harlin, ASE Certified Master Automobile Technician

The following are other ingredients found in Rain-X:

• Ethanol
• Rubbing alcohol
• Ethyl sulfate
• Chlorotrimethylsilane
• Siloxanes and silicones, di-me, hydroxy-terminated

Advantages of Homemade Windshield Water Repellent

Compared to their commercial counterparts, DIY windshield water repellents offer several advantages in terms of cost and safety.

First, homemade rain repellents are more affordable than commercial products. The ingredients you need to create a gallon of DIY water repellent cost much less than the various chemicals needed to manufacture Rain-X or another commercial product.

Second, a homemade windshield water repellent is safer to make and use. Neither the alcohol-vinegar formula nor the ethanol-alcohol mixture uses methanol. A toxic chemical used in commercial cleaning agents, methanol is harmful to human health.

How Long Does a Car Windshield Water Repellent Last?

Nothing lasts forever. Some windshield water repellents remain for several weeks. Others last longer.

Rain-X says that its Original Glass Treatment lasts around three months. The company adds that environmental and weather conditions can affect how long their product protects the windshield from water. The more it rains or snows, the faster the windshield water repellent fades.

When you notice that water stops beading on the windshield, reapply the rain repellent as soon as possible.

Is Applying Rain Repellent On Your Car’s Windshield Worth It?

You might wonder why people go to all the trouble of applying water repellent on the windshield of their car. Is it worth making homemade versions of windshield water repellent?

The answer is yes. When it works, windshield water repellent can keep the glass clean and clear of water. It reduces the need to operate the windshield wipers and makes the wipers’ job easier, reducing the wear on the parts.

Windshield water repellent also makes it easier to remove ice from the glass. Thus, a rain repellent is a good investment, especially if you can make it in your home.