Experimenting with Flexi-Glass Medium and Mica

Cabochon with bronze and gold mica
It seems like I always start my posts off with "a few weeks (or months) ago," "I took a class | read a book | learned a new technique..."  Well, this post is no different!

In May, I joined other members of the Glass Art Guild of Utah in attending a class taught by David Alcala (see previous blog post). One of the techniques David taught us was using his Flexi-Glass Medium.

Flexi-Glass is a thick liquid that you paint on a non-stick sheet, sprinkle glass frit or powder over the sheet, and then fire in a kiln to create thin, flexible "glass" sheets.  These sheets can be cut with scissors, easily torn, or punched, and then fired along with other fusible glass. This lets you create much more intricate shapes than you could ever cut by hand or with a ring saw. You can also mix the Flexi-Glass Medium with mica powders, spread the mixture on the non-stick sheet, and fire.

Flex-Glass Mica sheet
A couple of years ago, I purchased some mica powders. I've had varied success in working with them -- sometimes I like the results and other attempts have resulted in pieces that have hit the scrap bin. This weekend I decided to experiment with creating mica sheets using the Flexi-Glass. I wanted to start small with my experimentation, so I laid out a few cabochons.

In the photo on the right, you can see part of the Flexi-Glass sheet I created. I spread gold mica on one half of the sheet, bronze on the other, and then combined the two in the middle. Below left are the cabs ready to be fired -- I've used a colored glass for the base, placed mica cut-outs on top, and then capped with clear:

Cabochons waiting to be fired
Cabochons, out of the kiln!

I used a fairly "standard" (e.g., fast) firing schedule for the cabs.

The results are on the right.

I was somewhat concerned about the uneven texture of the mica sheet, and about what the pieces would look like after firing. I've had powdered mica "clump" on me, and I wondered if these sheets would do the same. However, I think the cabs turned out nicely. While I don't design a lot of jewelry these days, these little guys will probably end up as pendants.

I've currently got some larger pieces in the "big kiln" waiting for the kiln to be filled up so they can be fired. I'm concerned about bubbles near the mica sheet on larger pieces, so the largest piece right now has small glass chips at each of the four corners (fusers call these chads), to help air to escape during firing. The idea is the middle of the glass relaxes first, and then the glass relaxes outward, pushing air as it goes, resulting in fewer trapped air bubbles. I'll also make sure to include a nice long bubble squeeze in the firing schedule.

As always, I learned a few lessons with this experiment.

  • I have (since) read that adding some alcohol to the Flexi-Glass/mica powder mixture helps with smoothing out the powder. 
  • I like more organic edges on the mica sheet, so next time, I won't spread it so neatly on the non-stick sheet.
  • I should have cut my clear caps a little larger or the mica pieces a little smaller. I knew this, and did it anyway ;). If you look closely, you'll see some rough edges on the cabs as a result of the mica not being completely covered by the glass.

I'm going to continue to play with this technique. When the pieces in the big kiln are completed, I'll post some pictures. In the meantime, if you have any questions, let me know!

Happy fusing,
A finished cab using
Flexi-Glass and mica powders.


  1. We would love some of these cabs at Unity! The trees would go over well. Can you make some with Unity wings???? similar to this: http://www.unitync.net/Wings.html

  2. What an interesting process! The results are very impressive. Looking forward to seeing the bigger pieces.

  3. I've wondered about that stuff, thanks for sharing!

  4. Just gorgeous. Thank you for sharing. All the very best!

  5. Terri M Get2Give GlassworksOctober 29, 2013 at 8:48 PM

    I have the flexi glasd kit in my studio but havent tried it yet. How easy is it to cut? Which would u recommend scisdors or a craft knife? My impression is that the look is more organic than precise.... Thanks for the tip aboit adding alcohol. Propyl alcohol ie rubbinh alcohol? Enjoyed your blog article

    1. Terri, I cut some with scissors, some with a blade, used a punch, and then tore some. It is very easy to cut, but it was also very good at "holding together". Unless you are doing straight cuts and want to run the blade down the edge of a ruler, I would just use scissors or tear.

  6. Hi I tried to make cabs with mica and Flexi Glass, the mica buckled and did not lay flat. Can you share your firing schedule?

    1. Hello Sue, Did you cap with clear? I would think the clear is heavy enough to hold the mica sheet in place.

      I used a standard schedule that I would normally use for cabs, though I think I did add a short bubble squeeze. Probably 500/hr to 1100, hold 15, and then 500 to full fuse, hold.. 10? I didn't write the schedule down...

    2. I think this is exciting, I have recently bought F G;ass and the sheet, and I shall try tomorrow Monday, I started fusing glass last may shortly before I turned 80 ! 80 is the new 60 by the way. I live in Cornwall UK VR (SuperVirginia)

    3. Hello SuperVA -- I'm glad you found the blog and there are things here that are useful. Enjoy your fusing journey!


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