Starfish Reactive Tray


Oh, the joys of working with float glass! More and more glass artists are discovering the endless benefits and possibilities offered by using what is commonly-known as window glass for their creations. The difference between float glass and art glass hides within how the glass is made. Unlike art glass, float glass is made with a small amount of tin only on one side. This tin, combined with certain float frit colors, creates amazing reactions you will not find with art glass.  Float glass also costs much less than art glass and is often even available free as scrap. There are so many different techniques that make working with float glass sheet and frit very rewarding.

The custom reactive technique presented in this
tutorial will help you create a fun and crowd-pleasing tray. Products from will make the process fun and easy.

Supplies used:

Window Float Glass, 8″ x 8″ (2)

System 82 Float Glass Frit
Amber 0 Powder
Amber Size 4
Medium Size Giblets
Tools and Materials
Kiln Shelf Paper

Copper Mica Fine and Medium Enamel Sifters
UV-5F Lamp Tin Finder
Sharpie® Marker Pencil Writer
8‐1/2″ x 8‐1/2″ Square Slumping Mold

tutorial visual aid - numbered


1.   Gather all of your supplies, then clean both sides of the 8″ x 8″ float glass and the starfish shape. After you have cleaned the glass, you will need to find the tinned side of the float glass pieces. Only one side of the glass has the metal tin, and you cannot see it with the naked eye. Use the tin finder lamp and a Sharpie marker to find and mark the tin side of the glass, which is the one that glows from the ultraviolet light of the tin finder lamp. The side that does not have tin will not glow. Finding the tin side is significant, because we will be using both sides of the glass to create a reaction, a beautiful blue patina look that is unique to float glass.

2.    Place one of the 8″ x 8″ sheets in the kiln on kiln shelf paper, tin side up. Start with the second 8″ x 8″ float glass sheet tin side up. Place the Glassy Cuts float glass starfish, tin side down, on top of the 8″ x 8″ sheet. Lightly trace the starfish onto the second piece of glass with a Sharpie. The marker will burn off in the kiln. Remove the starfish and set it to the side.

3.   With a large sifter, lightly dust the Amber 0 powder all over the glass. Sift the powder so lightly that you can hardly see it. This will give a golden look to the tray. Too much and your tray will be less golden and more amber in color. With the medium size sifter, sift the Amber 0 powder a little heavier around the edges, undulating in and out to make the tray feel like the shoreline. Sift only enough powder for you to follow as a guideline.

4.   Use the medium sifter to gently dump small mounds of Amber 0 powder around the edges of the glass. By dumping material into these areas, there will be high and low areas, with some thicker than others.

5.   Fill in the starfish with taller and heavier mounds of the Amber 0 powder. These mounds will be part of creating the reaction we are looking for.

Note: To avoid wasting product, clean your workspace of the excess Amber powder and place it back into the jar. Make sure not to add fingerprints to the project while moving it.

6.   With your fingers, sprinkle Amber size 4 frit around the edge of the glass on top of the powder mounds. Add the frit to the starfish as well. Some frit may sprinkle onto the middle of the glass. That is okay, but don’t let too much get loose or your piece or it may be more spotted than you like.                                                                                                                                                                                                   Note: If too much sprinkles out, use tweezers or lightly wet your finger to pick up the excess. The wet finger trick also works if the powder spills onto an area where you would not prefer the frit to be.

7.   With a pencil writer, apply copper mica in swirl patterns on the starfish and all around the edge of the tray.

8.   Add the starfish shape and decorate the piece with the giblets. Place the Glassy Cuts starfish, tin side down, on top of the powder mounds and sprinkle the medium size Glassy Cuts giblets around the edge of the tray on top of the mounds. You can also create your own frit by crushing scrap float glass and sifting out the smaller pieces.

Note: Giblets are made from ground up float glass. Because the float glass has tin on one side, the giblets also have tin on one side. It’s a toss-up on which side of the the giblets will fall onto the powder. The side with the tin will have a reaction, and the side without will not. I chose to be surprised! The reaction happens because the amber frit is sandwiched between two pieces of glass where one is tin side up and one is tin side down. Also note that when sprinkling the giblets around the edge, you want to have big enough pieces that will show the reaction, but don’t let them hang over the edge.


9. This photo shows the piece after the first firing. You could stop there, but if you prefer, continue with a second slump firing using the 8″ x 8″ square slumping mold to finish the tray. Here are the suggested full fire and slumping schedules. Remember, though, that each kiln fires differently, so you may need to adjust the schedule for your kiln.

Float Glass Firing Schedule
Segment 1: Ramp 600°F/hr to 1510°F and hold 10 min. Segment 2: Ramp 9999 (AFAP*) to 1050°F and hold 30 min. Segment 3: Ramp 100°F/hr to 850°F and hold 15 min. Segment 4: Ramp 9999 (AFAP*) to 100°F and end.
*as fast as possible

Slumping Schedule
Segment 1: Ramp 300°F/hr to 1300°F and hold 10 min.
Segment 2: Ramp 9999 (AFAP*) to 1050°F and hold 45 min.
Segment 3: Ramp 75°F/hr to 850°F and hold 20 min.
Segment 4: Ramp 9999 (AFAP*) to 100°F and end.
*as fast as possible

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