Drying each layer of mould primer

Here, I share a little experiment to create some glass ankhs using a Colour de Verre glass mould 🙂

Wearing mask and safety glasses, I prepare the glass mould primer (I use Primo Primer, which is just mixed with water) and brush 4-5 coats onto the glass mould, drying each layer thoroughly with my  hairdryer!

The nice pink primer mix… stir it well during applications

Once dried, the glass mould is ready to be filled with glass frit and glass powders. Crushed dichroic glass, and copper, silver and gold foils are all fine too, as are very small inclusions. But bottle glass, Pyrex and float glass are not recommended for these moulds.

Primer brushed onto the glass mould

There are maximum ‘filling’ weights for each mould, so I weigh the mould before it’s filled with glass, and then weigh it again after filling. In the case of this particular mould, the maximum glass weights are 4 gr, 2 gr and 0.5 gr (large to small ankh size, respectively).

Mould filled with glass frit and powders, ready for the kiln


I created a custom program for the kiln, to frit cast and anneal COE 90 glass, using the advice of the mould manufacturer, Colour de Verre, and the excellent book, Contemporary Fused Glass by Brad Walker. A key point is not to fire above 1450 deg F as the primer could fuse to the glass (difficult to remove!). I also made sure I had a slow steady heat increase to protect the mould, to reach 1250 deg F from room temperature, before heating up to 1375 deg F to slump the glass. The annealing schedule begins 15 minutes after that and is a nice steady cooling schedule I use for all my glass working. So far, none of my pieces have broken, so I don’t change what isn’t broken!

The importance of glass COE!

For reasons undisclosed (!!), the glass used for my first casting experiment of the ankhs dared to include the blending of three types of COE:  COE 90, COE 96 and COE 104 🙂 Horror of horrors in the glass making world!!

So what’s the big deal?

Mixing COEs is NEVER EVER advisable, and many glass masters and books will tell you just the same… but always, at the back of one’s mind, the question is “what happens when you do!?”  Such questions sit silently in my deep unconscious and come out to play at the most critical of moments!

And on top of that artistic suicide mission, I used three different manufacturer brands for each COE type glass, which is rarely advisable even if they are the same COE type (if you do, then testing for each brands compatibility when mixed together is required before creating your art work).

I just hope Paul and Anushka are not reading this  section…!

My ‘petrified’ ankhs made up of three different COE types and brands!

So, the glass used for the ankh experiments shown here are, as follows:

  • COE 90 Bullseye frit: Bullseye Clear #1101;
  • COE 96 Reichenbach frit: Wine Red;
  • COE 96 Reichenbach ‘reduction’ frit: Iris Gold; Iris Blue; and, Smoke blue;
  • COE 96 Reichenbach ‘reduction’ powder: Iris Orange;
  • COE 104 Effetre frit: Bluestone; and, Goldstone.

This glass was used for the largest and 2 smallest ankhs in the mould. As you can see, they have a very petrified look!  No wonder…. 😉 That said, they are actually very beautiful to touch (even if a bit sticky spiky) and the colours have an ancient beauty to them, especially when the sun catches. Even though the COE incompatibility is obvious, this was a perfect experiment breaking all the rules which produced something that should not “be”, if that makes sense!? So I love and behold my first precious ankhs. Their secrets of longevity is proven somewhat here!

Note also that the ‘reduction’ frit glass has created some metallic sheens (‘reduction’ glass is used to create metallic sheens in lampworking – I added a  link below on ‘Iris Blue’ showing some examples of how it works with the torch). In the torch, you  significantly reduce the oxygen in the neutral flame (thereby vastly increasing the propane) to bring out the sheens in ‘reduction’ glass. In the kiln, this is clearly not something available and controlled, so I was surprised to see the ankhs held such properties!!

For the medium-size ankh, I used the following glass:

  • COE 90 Bullseye frit: Hand-made Turquoise Blue Opal #0116;
  • COE 90 Bullseye frit: Clear #1101; and, Egyptian Blue Opal #0164;
  • COE 96 Reichenbach ‘reduction’ frit: Iris Blue; and, Smoke blue;
  • COE 104 Effetre frit: Bluestone.

Another ‘petrified’ ankh

The kiln schedule for these ankhs will be evaluated on the next ankh experiment – this is an aspect of glass working that is continuously monitored, but clearly if one breaks the glass rules in the design preparation process, like I did here, then it removes the opportunity to perform any post design evaluation.

However, since these ankhs have not yet fractured, perhaps it is in part due to the excellent advice of Colour de Verre and Brad Walker… or maybe this is just magic!

Originally published: Wednesday, April 23rd, 2014 at 13:45 in Atelier, Inspiration


Tags: , , , , , , , , , , , , , , ,

No tags for this item


You can leave a response, or trackback from your own site.

2 Responses to “Casting glass ankhs”

  1. Coach M says:

    They look like ancient pieces found on the bottom of the ocean. Spiky as a sea urchin to the touch though. Ouch! :S

    • Perhaps those little spikes are for protection, as they are with all living things who have them? 🙂
      And there is more glass fun planned this weekend… I’ll post all my play! Enjoy all yours too!


Security question * Time limit is exhausted. Please reload CAPTCHA.

See also:

%d bloggers like this: