Plexiglass vs glass – pros and cons explained by an expert!


Plexiglass is lighter clearer and more expensive

Etched glass at Govinda's Restauran... x
Etched glass at Govinda's Restaurant, Tucson

If you’re debating between using glass or Plexiglass for a project, you may be wondering what the pros and cons of each are. A common misconception is that plexiglass is cheaper than glass – but this is not true. Here’s a breakdown of the differences between the two materials.

Plexiglass sneeze-guard
Plexiglass partitions are everywhere in the era of Covid

Plexiglass is lighter in weight and stronger than glass but it is more expensive and more easily scratched. It is clearer than glass but will yellow when exposed to UV light. Unlike glass, it can be easily machined: drilled, sawed, bent, and molded to form useful objects.

What is plexiglass?

Plexiglas® is the trade name for a type of acrylic sheet, made by the German company Roehm, from Poly(methyl methacrylate), or PMMA. It is now known by the generic name “Plexiglass“. Other brand names for the same product include Perspex®, Lucite®, and Acrylite®. For the purpose of this post, PMMA sheets will be referred to using the commonest US term: plexiglass.

Glass is a unique substance made by melting silica sand with various additives to make a vast range of clear or colored, transparent, or opaque products. Learn about annealed and tempered glass in this post.

Many products like windows, shelves, tabletops, and screens can be made with both plexiglass and glass. Read on to learn about the most important differences between the two materials.

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Differences between plexiglass & glass

Plexiglass and glass are both transparent, non-crystalline, man-made materials with very wide commercial, domestic and industrial uses in modern life.

Both glass types are available with modifications (mainly surface coatings) designed to improve their performance. These include UV coatings for plexiglass, anti-glare coatings for picture framing, stain-resisting coatings for shower doors, low-E coatings for insulated glass, and coatings for plexiglass to improve hardness (eg LUXACRYL®), and many more.

in order to make an apples-to-apples comparison, we compare regular plexiglass with regular tempered glass in this post – but always remember that many upgrades are available.

The most important differences are summarized below:

Plexiglass is lighter than glass but more expensive

Plexiglass is lighter clearer and more expensive

Plexiglass sheets are lighter in weight than glass making shipping less expensive and making handling and installation easier, especially for homeowners and non-professionals.

Contrary to popular misconception, however, plexiglass is more expensive than glass. Jump to these handy #price calculators to compare the weights and approximate retail pricing of plexiglass and tempered glass.


Plexiglass is easier to saw and drill than glass

Plexiglass can be drilled and sawed

Although some care and skill is needed to avoid chipping and cracking, plexiglass sheets can be cut by the home handyman using a table saw or circular saw with a fine-toothed blade. To protect the easily scratched surface, leave the protective paper on when sawing and drilling.


Plexiglass is easier to bend than glass

Bending plexiglass

Using a hairdryer or, better still, a heat gun (like this one available from Amazon), the handy homeowner can bend plexiglass to fabricate custom shapes at home. Bending glass is not a home project: it requires temperatures in excess of 1100 degrees F and can only be done in factories (or workshops with kilns).


Thin plexiglass can be cut by scoring

Scoring and breaking plexiglass

Thin (1/8″ to 1/4″) plexiglass sheets cut be cut by scoring with a special tool (available here from Amazon). After scoring, the plexiglass can then be broken apart by bending, as shown in the image above.

Cutting plexiglass by scoring
Plexiglass scoring tool has hooked blade

Use patience to make multiple scores, on both sides of the sheet, in order to remove enough material to create the break.

In contrast, glass cannot be cut once it has been tempered and even annealed glass is tricky to cut and drill without skill and special tools.


Plexiglass is clearer than glass – but may yellow in the sun

Plexiglass yellows in sunlight
Plexiglass starts out clearer than glass but will yellow in sunlight.

The transmissivity of plexiglass (up to 92%) is higher than that of glass (80 – 90%) so it looks clear even in thick sheets. For this reason, is often preferred for museum display applications. However, plexiglass can gradually turn yellow when exposed to UV (sunlight) light.

clear glass small image

In contrast to plexiglass, regular clear float glass has a pale green tint owing to a small iron content. Special, low-iron glass is available at a premium price but still is not as “clear” as plexiglass.


Plexiglass is stronger than glass

Plexiglass is more impact resistant than tempered glass

Regular plexiglass is much more impact resistant than annealed glass and also stronger than tempered (heat-strengthened) glass. The impact resistance of tempered glass is about 10 joules compared to 12 for plexiglass – explaining why you see plexiglass barriers around ice hockey rinks.

But note that polycarbonate (Lexan) is even stronger (up 200 joules). Lexan will be the subject of a future blog post.

Plexiglass breaks into angular fragments as shown in the image above – unlike the popcorn fragments of broken tempered (safety) glass. Learn more about tempered glass in this post.


Plexiglass is softer than glass

Scratch test show glass much harder than acrylic
Plexiglass is softer than glass

Plexiglass scratches much more easily than glass. Tempered glass (used for windows etc) has a hardness of about 6 on Moh’s scale (diamond = 10). So it can be scratched by carbide steel or quartz (hardness 7). The hardness of plexiglass is often measured on the “pencil” scale and is scratched by hard pencil lead (4H) – this translates to about 3 on Moh’s scale so plexiglass is considerably softer than glass.

Polishing scratches in plexiglass is somewhat easier (using fine sandpaper and plastic polish) than polishing glass but this benefit is offset by the higher vulnerability of acrylic scratching.


Plexiglass is flammable

Plexiglass has a melting point of approximately 265–285°F (130–140°C ), which is very much lower than that of glass (approx. 1000°C or 1830°F).

Plexiglass catches on fire at 450° Celsius which classifies it as a highly flammable material.

This can create issues in interior design because most State building codes prohibit the use of inflammable materials for interior walls and ceilings. This means that desktop plexiglass screens are OK, but room-height dividers and cubicles are prohibited by code.


Plexiglass is available in various colors

Plexiglass is available in numerous colors
Colored plexiglass sheets

Plexiglass is available in numerous both opaque and translucent colors whereas architectural glass (glass capable of being tempered) only comes in a limited range of tints. Other glass options include painted glass and so-called stained glass. Stained glass does come in an enormous range of colors but is only available in small sheets for use in leaded glass windows. Learn about the color in stained glass in this comprehensive post.

Environmental considerations

In this era of concern about climate change, the carbon footprint and sustainability of products have come under a detailed spotlight.

Mr. McGuire speaks to Benjamin
Mr. McGuire gives career advice to Benjamin in “The Graduate”

Mr. McGuire’s advice to Benjamin has turned out to be prophetic of the bête noire status of plastics in the modern ecological movement. Ignoring the obvious problems of plastic pollution in the oceans – what is the environmental footprint of plexiglass?

Acrylic (plexiglass)

The relative environmental impacts of plexiglass and glass are a complex matter to unravel and will be the subject of future posts. In brief, both glass and plexiglass are theoretically recyclable but, in practice, only 40% of glass is recycled and only 9% of plastics.

In terms of production, both products require energy but plexiglass production emits carbon dioxide, carbon monoxide, formaldehyde, and other compounds. This is very harmful to our environment. Acrylic is made out of petroleum and other toxic chemicals, a nonrenewable resource.

Artistry in Glass has gone to considerable steps to be ecologically responsible. and we conclude that glass is the lesser of two evils, as a cause of CO2 generation, when it comes to production. Since glass is endlessly recyclable, it is also preferable to plexiglass especially as more measures are taken to promote recycling.


Examples of applications plexiglass vs glass

Plexiglass vs glass for wall shelves

Whether you choose plexiglass or glass, it is always cheaper to purchase ready-made shelving systems rather than custom sizes. So, unless you have a special location that requires exactly sized shelves – it is sensible to save money on standard sizes.

Notice the benefit of simple plexiglass shelves below is that, unlike glass shelving, brackets are not required

The fact that plexiglass can be bent makes these shelves installable without metal brackets. Clear acrylic shelves from Amazon are 5mm thick, 12 inches long for bedroom, living room, or, bathroom – set of four


Standard sized glass shelves are also affordable but must be purchased together with supporting brackets – like this example below:

Available on Amazon these bathroom shelves are 24inches long & made of 5/16″ thick tempered glass with polished chrome brackets. More stylish and stronger than plexiglass but more expensive

In conclusion: choose plexiglass shelves if you are on a budget, but glass shelves for style and elegance.


Insider tips from a glass professional

Money-saving tip! Glass and mirror are essentially the same quality whichever shop you purchase them from. So save money by using these glass-buying tips from the experts at Artistry in Glass.


Useful price & weight calculators


1/8″ glass v 1/8″ plexiglass

1/4″ glass v 1/4″ plexiglass

3/8″ glass v 3/8″ plexiglass


Remember that the pricing modules above are just basic guides for custom sizes – big city costs will likely be higher and prices for standard-sized sheets may be lower.

Conclusion

Plexiglass is a strong, lightweight material that is clear and easy to machine. It can be used in place of glass for many applications, but it is more expensive and scratches more easily. It is important to consider the pros and cons of acrylic before making a decision about whether to use it in your next project. Call Artistry in Glass for detailed advice on the suitability of glass or plexiglass for your project.



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John

I was an exploration geologist and University Professor working in Botswana, Zambia, Brazil, Saudi Arabia, the Netherlands, and other countries before opening Artistry in Glass in 1986. In my more than 30 years of experience, I have brought my technical abilities as a scientist to the trade of glasswork. In this time I have become an industry expert in glass and glass-related skills. Watch out for special insider tips developed from my detailed knowledge of the glass business.

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