Everything you need to know about glass edge finishes

Introduction

Welcome to the Dulles Glass guide on everything you need to know about edge finishes for glass table tops, shelves and mirrors

Let's start with: What is a glass edge finish and why is it necessary? 

Glass is a commodity and comes in large sheets of various sizes in different thicknesses. Unlike popular belief, glass is not cut into desired pieces and is “Scored” and then “Broken”. This creates a dangerous sharp edge all around the glass. To make glass safe to handle all edges must be grounded. There are different machines that can grind the glass edges in order to produce the final “edge finish”. The edge finish choice is based on function, aesthetics and other factors. 

During glass fabrication, glass is scored, broken and the first destination after that is the glass edging machinery, all other processes are done after the glass edges are finished. This will make the glass safer to handle during the fabrication process.

There are multiple ways to process the edges depending on the intended use and customer preference.

Seam Edges:

This process is done by lightly sanding all edges and corners to remove the sharpness so glass can be tempered and also handled by the end user. The finish will be very dull, not highly polished and less safe to handle than glass with a Flat Polish. This type of edge is used in cases where the glass will be encapsulated within a frame so edges will not be seen from outside.

Flat Polished Edges: 

This type of process is done with machines which grind sharp (right-angled) edges to create 45 degree arris flattened corners. A flat polished edge is the most popular type of edge in the glass furniture industry. Aesthetically all the edges will be highly polished and have a smooth final finish. This kind of edge can be exposed (not within a frame), since there are no sharp corners and offers a simple but finished look.
A Straight line Flat Polishing machine would be used to create this edge finish. The machine has a series of different types of grinding and polishing wheels to perform the polishing of the edges. The machine also uses high pressure water to keep the wheels and glass from breaking during the process. The first 4 wheels are heavy grit diamond wheels which grind and flatten the edge surface. The following series of wheels are less abrasive to further smoothen the surface. 4 more wheels then grind and polish the arris corners to a 45 degree angle. The final 2 wheels are soft polishing wheels which give the high polished finishes to edges of the glass.

Pencil Polished Edges: 

This type of edging is also created by specialist machinery. This is quite similar to the Flat Polish machine and uses the same process. The unique difference is the type of wheel which is shaped Concave (Curved inward) to give the glass the Convex (curved outward) finish. To accomplish this kind of edge, the wheel will spin at 90 degrees to capture the edge of the glass. The first wheels are heavy grit diamond wheels which grind and flatten. The following series of wheels further smooth the edges, with the final 2 wheels much less abrasive to leave a smooth polished edge.

Beveled Polished Edges:

Machinery used to create beveled edges is far more sophisticated and expensive compared to Flat and Pencil Polish edge machines. The process is slower as bevel machines will grind and polish not only the edge but an area of the perpendicular surface. Depending on the desired width of the bevel, more or less of the surface will be grinded and polished.  These machines also use a series of different diamond wheels with different grits to accomplish the desired finish. Due to the need for grinding and polishing of the surface, which the wheels alone would not achieve, Cerium Oxide is introduced into the process. High pressure water is used to clean and keep the glass and wheel cool, preventing glass breakage. 

The process uses all of the wheels set to a certain angle, depending on the desired bevel width and glass thickness.  Similar to Flat Polish and Pencil Polish machines, glass will run through a series of wheels to grind and smooth the edges and surface of the glass. The final 2 wheels will have Cerium Oxide sprayed on to them to accomplish the required high polish finish to all ground edges and surfaces.

Miter Edge: 

The glass edge is cut at an angle to accommodate a finished corner where two pieces of glass will meet. Miter is a type of edge which is used when 2 glass panels are required to join at a specific angle. The angle of the miter may vary, with thinner glass, such as ¼” thick, usually cut at an angle of approximately 22 degrees.  Miters for thicker glass, i.e. ⅜” and above can be cut at an angle of up to 50 degrees.  
Miter edges are fabricated using Flat Polish edge machines. The same series of wheels are used for Flat Polish edges, but all the wheels will be angled to grind and polish. Unlike a Bevel Polish, Miter polish grinding and polish is performed along the edge only and not on the perpendicular surface as with a bevel.

Ogee Finish: 

A  dual arched design resembling two pencil edge finishes along two horizontal planes.

What types of glass edge finishes are there for mirrors? 

• Mirrors are normally ¼” thick or less, so not all common glass edge finishes are available for mirrors.
• If the mirror is framed all around then the best option would be a seamed edge since the roughness around the edges will be hidden inside the frame finishes on mirrors are less pronounced and making it hard to distinguish between Flat and Pencil Polish options. 
• If the edges are exposed and the mirrors are multi mirrors being installed next to each other, the best edge type is Flat Polish.
• If it is a single mirror being installed with no frame, the option of Beveled Edge can be applied to create the look of a beveled frame around the mirror, or a Flat Polish can be chosen for a minimalistic look.

Is a smooth and safe edge the same as a Flat Polished edge? 

Yes, a Flat Polished edge is sometimes referred to as a smooth and safe edge.

What is the difference between Beveled or Pencil edge? 

A Pencil edge is a half rounded smooth edge whereas a beveled edge is where the surface of the glass is grounded at an angle to create a beveled look with a smooth polish at the edges of the glass.

How thick is a Beveled edge? 

A Beveled edge can be applied to glass that is thicker than ¼”, anything thinner would not be able to accommodate a beveled edge.

How wide is the bevel on a glass mirror or table top?

The max width of a bevel is determined by the shape and thickness of the glass.  For rectangle and square table tops and mirrors, the width of the bevel can usually be up to 1 ¾” wide.  For oval and round glass, the maximum bevel may be smaller.

Below is a table to guide you based on average industry bevel limitations:

Glass Table Tops and Shelves, average maximum bevel width

*Please note, this is a rule of thumb. Some manufacturers may be able to offer more or less bevel width than described in the table above.

Glass Mirrors, average maximum bevel width

*Please note, this is a rule of thumb. Some manufacturers may be able to offer more or less bevel width than described in the table above.

How do I choose the right edge finish? 

Choosing the right finish will depend on many factors including function aesthetics and other factors. Here are some of the criteria that will impact the decision making:

• If the glass or mirror is placed in a  frame the most popular choice of edge finish is Seamed Edge.
• If there are multiple mirrors or glass prices to be installed adjacent to each other, the most popular edge finish option would be Flat polish.
• If the edges of glass are exposed, most popular finishes would be Beveled edge, Pencil edge or Flat polished.

Are there additional edge finishes for table tops? 

The most popular edge finish for table tops is Flat polish, Beveled edge or Pencil polish, the choice is more about preference and aesthetics and is dependent on decor and users taste.

What is a safety edge on a glass table top?

If you have children or pets at home, safety becomes a primary concern. In such cases, rounded edge finish like pencil polished can be safer options compared to sharp, unpolished edges.  A Flat Polish edge or a Beveled edge are also considered safe options.

What are the specific measurements of a bevel on a glass table top?

The width and gradient of a bevel will vary between table tops. However, if a bevel is 1" wide, as a rule of thumb the bevel may reduce the glass thickness by 1/16". 

Are the edges of a glass table top green?

Glass, particularly when viewed from the side (or along a horizontal plane), will have a green or bluish tint.  The level of colour will be dependent on the iron content in the glass as well as the ambient light, the viewing angle and thickness of the glass. Low iron glass or HD glass is clearer, but glass is never 100% without some level of tint.

Are there different edge finish options for a glass backsplash? 

The most popular edge type for glass backsplash is a flat polish, this is to make sure when the adjacent pieces of glass are lined up against each other the join between pieces of glass are not as noticeable. 

Can I order glass with an edge finish on only one side?

Yes you can. Companies that are specialized in customization of glass can manufacture glass to your specifications.

Did you know?
Some irons in glass will conduct electricity

Lower ion content in glass will improve the resistance of the glass to thermal shock, for example putting ice on glass followed by hot water (we do not recommend this!). However if you are looking for a glass outdoor patio table table, HD or Low iron glass will be even more resistant to temperature fluctuations than standard clear glass.