I love making sushi dishes with bubble powder as it creates totally unique dishes each time I use it.
What is bubble powder? It is a fine fusing powder that, when sprinkled between two pieces of glass, will form blisters of colour, pushing up bubbles onto the surface of the glass.
"Ocean Floor" fused glass sushi dishes by Glassprimitif
I sell bubble powder that is COE82. This means that it will fuse with picture (float) glass only. As picture glass is so cheap compared to other art glass, this makes bubble powder a great medium to experiment with. http://www.etsy.com/view_listing.php?listing_id=8354683
Bubble powder comes in two grades: the finest powder is called Bubble Classic (shown above) and forms large blisters in between the glass in deep, liquid colours. Boreal Bubble is a coarser grain and forms small pock marks in the glass in bright colours. I like to mix the Classic with the Boreal to add texture to the glass too. Bubble powder comes in wonderful colours such as yellow, turquoise, cobalt, Boreal red, Boreal orange and ruby gold. By mixing colours together you can add a third colour to your glass. For example, mixing turquoise and yellow will give a rich green sheen to your glass, as seen below.
"Forest Floor" fused glass sushi dish by Glassprimitif
To use the powder: shake a small amount of powder over a piece of clean float glass and cap with another piece of float glass. Fuse to your usual fusing schedule. Where the powder is thicker, larger bubbles will form inside the glass. If you intend to slump the glass then choose a shallow mold or the bubbles will fracture if they slump too deeply.
Caution: when handling the powder, remember to use surgical gloves and to wear a mask. Wash hands immediately after use and wipe up any surplus powder.
"Pink Bubblegum" fused glass pendant using ruby gold Boreal bubble powder http://www.etsy.com/view_listing.php?listing_id=8296137
Stained glass suppliers Delphi from the United States also sell bubble powder which is co-efficient with all types of glass but, as I have never used it, I can't vouch for it. http://www.delphiglass.com/