Layered Checkerboard Bowl

[print-me]

This piece was inspired by my interest in a more 3D approach to fused glass pieces, combined with a few pieces I had admired previously that displayed a beautiful repeating pattern of transmitted and reflected light.

Being a geometric guy, and looking for a simple repeating pattern, the chess board design seemed like a great starting point. I then added an easy to achieve 3D affect that I think you will like.

The first and most obvious requirement was that the piece transmitted light and hence had to be made primarily of transparent glass. Opaque glass would reflect light and seriously affect the play of colours achieved through the transmitted light and overlapping colours, and that would not work.

So the final idea was to have two layers of glass squares in good contrasting colours, but instead of butting together, I decided on an air gap between each square, with the two layers slightly overlapping.

My mold would take a 270 mm x 270 mm square piece so a little maths resulted in the first layer being made up of 49 squares of 30mm each,  in a 7 x 7 grid. A 10mm air gap between each row and square. The top layer is made up of 36 squares of 30 mm. Each square overlaps four of the bottom squares, effectively tying the whole piece together.

The colours I chose were simple transparent clear for the bottom, and for the top layer a light violet, Bullseye 1428 .

Because I was using transparent glass I did draw up the design on the Bullseye Thinfire kiln paper. By doing this I had a handy guide that could be used when laying up the squares.

So next task was to cut all the squares and clean them. Be sure to clean them well as you really don’t want any devitrification to hinder the transmission of light.

     Place the Thinfire paper on your kiln shelf and proceed to lay up. I suggest you lay up two rows of clear on the bottom then a row of the overlapping top layer squares. When that is done and nicely lined up, add another row of the bottom squares then another of the top squares, working your way across the design. If you add all the bottom squares then try to add the top layer you may find yourself forever realigning the bottom squares after you inevitably nudge them.

Once laid up, double check everything is still in place and then off to the kiln. The firing schedule I used is below. Keep in mind, as usual, this was for my kiln and yours will most likely behave differently.

It should come out of the kiln something like this photo. You can fuse less or more, depending on the final result you are looking for. This worked out well for me, resulting in that 3d effect I was after.

Once fused, you may need to do some clean up if there are any sharp edges. A little sanding with a diamond pad, or even wet and dry sandpaper, will do the trick. make sure to use a fine grade. This will fire polish in the slump.

When you are happy with the preparation give the piece a final clean and place in your mold. I always use boron nitride (MR-97) on my molds. It works perfectly and is so much easier to get a great finish on the piece.The slump firing schedule is below. Note that the top processing temp is lower than normal due to the thinner construction of this plate.

Give this a go. It is well worth the effort and try different colours.  I can imagine yellow and blue resulting in green shades of transmitted light. Many colours should work well together.

Firing Schedule

Tack Fuse

Please be aware that all kilns fire differently and this schedule may not produce the same results in your kiln.

Segment	Rate (C/hr)	Target (C)	Hold (mns)
1. Release	222	537	10
2. Process	333	760	5
3. Anneal	Full	516	30
4. Cool	83	371	10

Slump

Segment	Rate (C/hr)	Target (C)	Hold (mns)
1. Process	167	630	0
2. Anneal	Full	516	90
4. Cool	83	371	30