Chemistry in action – Use of Reactive Red Glass
How could I resist? The web sales sites offered what looked like ordinary clear or white opaque glass but promised surprising colors after fusing. Yes, I was lured into the world of reactive glass.
The concept is simple, when 2 dissimilar but specific chemicals come into contact at extreme temperatures, a reaction occurs which results in a new color in the fused glass. So what’s the key to this reaction? There are several chemical combos as well as differing degrees of reaction. In many cases, sulfur or selenium will react with copper or lead. ‘Aha!’ you exclaim – that must mean I need to use some green or blue glass. This is true since copper often is what gives the green and blue hues (but not always). Glass labelled as teal, cyan, or turquiose are pretty good bets to have lots of copper. Although the element itself is yellow, sulfur contributes to many red and pink glasses.
But wait. I’ve been fusing with lots of blue glasses and haven’t seen unexpected new colors in my finished product. The key is to have the neighboring glass in the fusing process have lots of a reactive chemical such as selenium. Most glasses in my inventory (or in general) will not have high enough levels to cause a reaction. This is where glass manufacturers such as System 96 or Bullseye step in to entice the glass artist.
‘Red reactive’ glass is sold in transparent and opaque sheets, stringers, and frit. When fired in contact with certain glasses (with high copper content), a red color results. Manufacturers publish recommended glass types for use with their red reactive product. Copper or silver foil can also be used.
Too good to be true? Maybe. There is a hidden catch in all this chemical magic. The reaction only occurs at the interface between the 2 glass types. This means your piece will not turn red everywhere. For maximum effect, you need to maximize the interface. Understanding this, I focused on using blue stringers and frit fused onto opaque reactive red glass (which looks white).
Here is a close up of my first experiment:
Notice the red outline around feature. This is the red reaction. It really looks like the glass frit had a small explosion leaving a burn mark around each one.
I would be hard pressed to call this piece red. It is a neat effect but really subtle. Understanding and embracing this, I created a set of coasters as well as the plate shown at the beginning of this post.
I will continue to play with reactive glass but I’m not sold on its expense. Feeling underwhelmed, I wonder if I should have titled this post – Barely Getting a Reaction?