Choosing the Best Size Copper Foil for Stained Glass

Ashley Christensen
January 30, 2023

A common hurdle that many who are beginning to work with stained glass will be faced with, is deciding what size of copper foil to use. With all the different choices available, it can appear daunting or overwhelming to decide what size to use over another choice. Before you can make a decision, it is good to know what options are available. The different sizes of copper foil will vary in width, thickness, and backing color, which are all things to take into consideration. 


The most common widths of copper foil include 3/16”, 7/32”, 1/4”, 3/8 “, and 1/2” 


Typically copper foil comes in 1mm and 1.5mm thickness. Occasionally you can find 1.25mm thick foil as well. 

Backing Color

Foil is available in three different backing colors–silver, copper, or black. Typically the backing color is selected based on the finished color of solder that will be used. 

Characteristics of Good Copper Foil

Not all copper foil is going to be the same quality, some will be better than others, and some will work better for your project than others. Copper foil's essential function is to allow pieces of glass to be soldered together to create a masterpiece of various stained glass pieces. Because the solder won’t still have to glass itself, it needs a good quality foil to help it adhere. Think of the foil as the foundation of the stained glass piece. 

A good quality foil will be flexible enough that it can form around all the different shapes that fit together to create your finished piece. In order to be able to fit around each individual piece, the foil will need to be stretchy enough that it won’t tear or split when forming to inside curves. Also take into consideration the softness of the foil, as the softness will factor into how well it stretches. Finally, a good quality copper foil will be strong and adhere to the glass well, so that it can be burnished (rubbed smooth), and remove all kinks without ripping or tearing. 

4 Things to Consider When deciding on the size of Copper Foil to Use

Now that you know what types of copper foil are available, and what characteristics make a good quality copper foil, here are four things to take into consideration to decide on the right copper foil for your specific project. 

Size of Your Project 

For the vast majority of stained glass projects, the appropriate size of copper foil will be either 3/16“ or 1/4“. Opting to use anything wider can make a project appear heavy compared to the size of the overall pieces. 

The Thickness of the Glass

Not all stained glass is going to be the same thickness, which is why you need to take it into consideration when selecting the copper foil you’ll be using. The foil that you select needs to be wide enough that it wraps around the front and back of the glass equally, to create stability in the pieces. When you solder the front and back of a project along the seam, you are essentially creating your own “i’ beam. The solder will seep between the two pieces of glass that are being soldered together, when enough solder has been added to the front and back, it makes a shape that then secures the two pieces of glass together. The final width of a seam is determined not by how much solder is used, but instead by the width of the foil that is used. 


After you determine the structural needs of the project, the next thing you need to consider is the overall look and appearance that you are trying to achieve. If you tend to lean towards heavier lead lines, you’ll want a wider foil. The opposite goes if you are looking for a lighter appearance, you’ll want a narrow foil. 

Artistic Design 

A combination of wide and narrow foils, creating thicker and heavier lines mixed in with narrower and lighter lines can help to give a project dimension and depth. Different thicknesses in foil will allow you to give emphasis or focus on specific areas that you want the eye drawn to. 

Gordon’s Glass is your local, stained glass supply shop. With a wide variety of copper foil available in various sizes, thicknesses, and colored backing, you are sure to find the right copper foil to complete your stained glass masterpiece. Stop into Gordon’s Glass today and get started on your next stained glass project. 

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