Should You Use A Razor Blade On Glass Surfaces?

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Some swear by using a razor blade to clean glass surfaces, while others say it’s a quick way to ruin a good window. So can you use a razor blade on glass surfaces without scratching them? It depends on the type of glass and the blade you use.

Use a professional-grade, double-sided razor blade specifically designed for cleaning glass. Wet the glass with soapy water and scrape in one direction at a low angle. Test the blade on an inconspicuous area of the glass first. Avoid using a razor blade on tempered or coated glass.

Let’s look at whether a razor blade will scratch glass and if you can clean a window with one. You’ll also find out which types of glass won’t scratch and get tips for using a razor blade on glass surfaces.

Will a Razor Blade Scratch Glass?

Detailer using razor blade for scraping off excess repair resin

It depends. A razor blade can scratch glass depending on the type of glass, the blade you’re using, and how you use it. Using a new, sharp blade at a low angle is the best way to avoid scratching your glass.

Razor blades are martensitic stainless steel, hard but brittle steel made by adding carbon to iron. The blades are tempered or heated and cooled to improve their strength and hardness.

The Rockwell scale measures the hardness of steel—the higher the number, the harder the blade. For example, most razor blades have a Rockwell hardness rating of C (60-66). In comparison, window glass has a hardness of about 5.5 on the Mohs scale, which measures the hardness of minerals.

A razor blade is much harder than glass and will scratch it if misused or on certain types of glass.

Coated Glass

Razor blades can damage coated glass if the coating is on the surface of the glass rather than between layers. The coating improves its durability and appearance or ”self-cleans” the glass. A razor blade will scratch the coating, leading to streaks, marks, or other blemishes.

The three main types of coatings are:

  • Hydrophobic Coatings: Causes water to bead up and roll off the glass, making it easier to clean; they also help prevent mineral deposits from forming.
  • Hydrophilic Coatings: Attracts water and helps it to spread evenly over the surface of the glass, making it easier to clean and prevent streaking.
  • UV-Resistant Coatings: Protects the glass from fading and other damage caused by ultraviolet light.

If you’re unsure if your glass is coated, look for a manufacturer’s warranty that includes information on cleaning the glass.

Tempered Glass

Tempered glass is a type of safety glass that is heated and cooled to create a more robust, durable surface. As a result, when it breaks, it shatters into small, safe pieces rather than large shards.

During the manufacturing process, debris may bond with the surface. Using a razor blade to clean tempered glass can displace this debris and drag it across the surface, causing scratches.

Privacy Film

Privacy film is a thin, Polyethylene Terephthalate (PET) film applied to glass windows and doors. It’s available in various colors, designs, and opacities to provide privacy while allowing light to enter the room.

Films are usually applied to the inner surface of the glass but may also be applied to the outside. Avoid using a razor blade on the surface the film is applied to because it will leave scratches.

Can You Clean a Window with a Razor Blade?

In most circumstances, using a razor blade on glass surfaces is not recommended because it’s easy to scratch the glass.

If you must clean your windows with a razor blade:

  • Wash the glass first to remove any loose dirt or debris. Then lubricate the surface by wetting it with soapy water and use a new, sharp blade held at a low angle. Work slowly and carefully to avoid scratches.
  • It’s also a good idea to test the blade on an inconspicuous glass area before cleaning the entire window.
  • Start in a corner and move the blade horizontally or vertically across the surface. Use gentle, even pressure to scrape any debris from the glass using short strokes in one direction.
  • Avoid pressing too hard or using a back-and-forth motion, which can increase the risk of scratches. When finished, rinse the area with clean water and dry it with a lint-free cloth.

If you’re concerned about scratching the glass, use a putty knife or a professional-grade glass scraper (on Amazon) instead.

Which Glass Types Won’t Scratch?

Untreated and uncoated, annealed, also called float glass, is less likely to be damaged by razor blades. Typically, single and double-pane windows, tabletops, and cabinet doors are made of this type of glass.

Borosilicate is heat-resistant glass used in cookware, scientific equipment, and lighting. It is also unlikely to sustain scratches if cleaned with a razor blade.

The most crucial aspect is whether the glass is treated with any coating because these can be more easily scratched.

For example, tempered glass is heat-treated to make it stronger, but this process makes the surface more brittle and prone to scratches. Low-E (low-emissivity) coatings are applied to windows to reflect heat and reduce energy costs, but they’re also more susceptible to being damaged by a razor blade.

If you’re not sure what type of glass you have, it’s always best to err on the side of caution and avoid using a razor blade for cleaning. Instead, opt for a safer method, like using a squeegee or microfiber cloth.

Tips to Keep in Mind

Cleaning dirty surface of black ceramic hob

If you are going to use a razor blade, these are some essential tips to keep in mind:

Use a Professional Grade Glass Scraper

Choose a scraper that’s made specifically for glass. These have a rubber grip to help prevent slippage. Some, like this one from Mulwark (on Amazon), come with a few different blade options, so you can choose the one that’s right for your needs.

Replace Dull Blades

A dull blade is more likely to scratch glass, so make sure you’re using a sharp one. And don’t use the blade for anything else besides glass, as this can dull it more quickly. Finally, inspect the edge for rust, chips, or nicks before each use.

Test the Blade First

Before you scrape, test the blade on an inconspicuous glass area to ensure it will not scratch. Do not proceed with cleaning if the blade leaves a mark.

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