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Flash Play Day via Zoom

November 18, 2023 @ 9:30 am – 10:30 am Pacific Time: Zoom

Create flashed glass as described in the November Newsletter and then use it as described below to create an interesting pattern for the newsletter’s Flash Challenge. Hosted by Karen Seymour.

Play Days are only for Guild Members. Please join the guild before attending the Zoom. This is designed as 3 Zooms since it is almost all kilnwork and cutting. You can attend in person if you let me know you are coming but it will be a presentation to the camera so no one should feel left out of the discussion. Please contact Karen Seymour if you have questions

Process

First some design guidelines to make it easier (feel free to break them if you think you know what you’re doing):
• 1 or 2 colors (take care if you use reactive colors and will stack them near each other: the usual fix of a coat of clear powder will probably get stretched too thin to work here so you may get a dark line at the interface)

• About 4″ square, circle or other shape is a good size to test with. You don’t waste too much glass if your idea needs refinement but it’s large enough to see most effects.

• Don’t go more than 3/4″ thick in step 2 (this size is easy to cut and your annealing time won’t take forever)

• Be sure your kiln shelf is level so your glass doesn’t run off (or, more likely, become wedge shaped).

Take photos before and after each firing. It will help with troubleshooting. We’ll hold a Zoom meeting at 9:30 am November 18th to discuss ideas before getting started . I’ll send the link to all members in the Member News email earlier that week or you can log on and find the link above.

*firing schedules are for my kiln using Bullseye glass. Your kiln and glass may differ.

1) sift a uniform 1/16″ thick layer of colored opaque powder on a 4.5″ wide rectangle of 3mm clear (opaque will work better than transparent color for this pattern making test). What if you use a stencil?
Fire*
350 degrees/hour to 1180 degrees F, hold 30 minutes
100 degrees/hour to 1225 degrees F, no hold
As Fast As Possible to 1400 degrees F, hold 5 minutes
AFAP to 900 degrees F, hold 1 hour
100 degrees/hour to 700 degrees F, no hold
300 degrees/hour to 100 degrees F, no hold

2) Cut off any thickened edges then cut 3/4″ strips.
Stack them edgewise with intervening strips of clear with in a way that you think will be interesting. Use a dam which is kiln washed or rimmed with fiber paper.
Fire* 3/4 thick at
(other thicknesses will change the anneal):
300 degrees/hour to 1180 degrees F, hold 30 minutes
100 degrees/hour to 1225 degrees F, no hold
AFAP to 1490 degrees F, hold 10 minutes
AFAP to 900 degrees F, hold 3 hour
45 degrees/hour to 800 degrees F, no hold
81 degrees/hour to 700 degrees F, no hold
270 degrees/hour to 100 degrees F, no hold

If you are trying to make a sculptural piece (these were prototypes for a tabletop) you can stop here or try a drop vase etc.

3) Fire again to flatten the block to 6mm or thinner :
Use a primed kiln shelf, not shelf paper (i.e. not Thinfire) because the glass will be moving.

Squashing or Kiln-pressing: If you place another primed shelf on top and add some more weights with stainless steel washers or fiber paper to keep it from going too flat, it will be thinner and make a lighter piece but the pattern may distort more (the center of the piece is what moves most: like the marshmallow in a som’more) and you’ll need to hold a bit longer to get everything to temperature. Fire to firepolish (1325F) after squashing if you want it shiny.

See the image in the mold below for the result

Fire* without squashing (with squashing);
200 degrees/hour to 1200 degrees F, hold 1 hour (3 hours)
AFAP to 1515 degrees F, hold 1 hour (2 hours)
AFAP to 900 degrees F, hold 1 hour
100 degrees/hour to 700 degrees F, no hold
300 degrees/hour to 100 degrees F, no hold

(Zoom, probably Dec. 16th, to share results and discuss further ideas)

4) Slump as normal for your mold if you wish a bowl or other shape. Bullseye’s cone mold with 1/4″ fiber lift in the bottom is what was used here.

What do you think will happen when I flatten the concentric squares on the left?