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In order to keep our tutorials simple for this web site, we have kept the verbiage to a minimum  There is a lot left up to the viewer to discover. We hope you enjoy these and find them useful.

More than you ever wanted to know about mica and glass.

Recently I have seen several posts on using mica on glass. Lots of answers were given, some right and many wrong. I have worked with and actually studied mica for the last 10 years. This includes  testing over 1000 different micas. Why so many? There are many mica manufacturers worldwide. Each manufacturer makes many types and colors. You would be amazed a how micas vary...even within the same color group (like gold has hundreds,).

What the heck is mica?

Basically mica is a mineral. It is highly temperature resistant and is actually used for many high temperature operations. It is usually  clear in color and often comes in flat plates. It is not what you see sold as colored mica. Colored mica that you see for sale is finely ground mica particles coated with a coloring agent. Thus you see the beautiful mica powder.

What is mica used for?

By far far far the largest uses are cosmetics and paints. It is also used in electrical componenets and electronics. The people who make these micas could not care less about temperature stability of colors. Thus, fusing is not on their radar. Recently I found a manufacturer whose micas are used  in specialty high temperature baked on auto paints. The results come a lot closer to what we want (still not perfect, but very good),. These are the micas we are distributing.

How is  mica colored?

The mica particle is plated (I do not know how) with different coloring agents. For the metallic colors.., the most popular agents are titanium dioxide and iron oxide., along with oxides of various other metals. Many of these offer stability at elevated temperatures.. Now comes the problem. For the cooler colors (blue, violet and green), most of the  coloring agents used are not stable at elevated temperatures. In fact probably 99 percent  are not stable at high temperatures.

The blue, green, and violet micas that we have use a unique method of coloration. This new method uses varying micro molecular particle sizes of Titanium dioxide, plated to the mica to create diffusion colors . Again, this can get very complicated, so I will try to simplify. The varying titanium dioxide particle size acts as a selective prism to create a color based on the size. These we call interference colors and are more stable then the coloring agents in general use.

Properties important to fusing mica.

There are two critical properties for dusing of colored mica. The first is the overall particle size. I won’t go into a dissertation about the sizes of mica particles. It starts very small. In mica terms this is called a satin mica. Next in size comes what is referred to as luster sized. Then comes a larger size referred to as sparkle. Then larger comes glitter. Obviously, the larger the size, the greater the weight. This will  become important later in this discussion.

The second property of fusing mica is the coloring agent. There are a whole slew of coloring agents for the different colors. The metallics vary in weight. So do the non-metallics. Again this will become important shortly..

How does mica fuse with glass.

Mica does not interact with glass. There is no chemical bond. It is strictly a physical bond. As the glass is heated and softens, the mica sinks into the glass and the glass holds the mica in place. It is physically captured by the glass. And here ladies and gentlemen comes the most important thing in adding mica to glass...GRAVITY.

Yes folks, when we fuse the glass that the mica sits on it becomes soft. Well, the heavier the particle of mica, the more it will sink into the glass. This is why the metallics do better than the non-metallics . They are heavier.

But! There is also the particle size to consider. The larger the particle, the less resistance the liquid glass has to the particle sinking . Due to surface tension, the smaller particles sometimes rest on the surface.

Enhancing your mica color!

We have found a way to enhance both the adherence and the color of mica on glass. We use a Kaiser Glass Paint that is similar in color to the mica, and sprinkle mica on the wet paint. We gently pat this down and then dry the paint. The mica adheres beautifully to the glass. Once dry we brush off the excess and voila....a gorgeous mica on glass.

Summing it up!

As you can see there are lots of considerations to make in order to decide on what mica to use on glass. There are numerous compromises that need to be made. We as a supplier wanted to have the best possible mica for use with glass,. So we compromised in making available micas that fit the needs of most, but not all fusers.

This is not your usual “How To” tutorial.

It is an informational tutorial about Mica