Glass Fused Snowflake

Overview

This blog describes how to make a simple glass fused snowflake.

Components

Cut several strips of clear glass about 1/4" wide. Approximately three feet is needed for one snowflake.

Cut Strips

Break on score

Strips

From the clear strips, cut the follow:

• Six pieces 2 1/2" long
• Twelve pieces 1" long
• Twelve pieces 3/4" long

Cut six squares approximately 1/2" wide from green transparent glass. Remove the corners to form crude circles. Save the chips (corners) for later use.

1/2" squares

Squares, corners removed

In a similar fashion, cut one 1/2" circle from clear glass.

The picture below shows the components necessary to create one snowflake:


Parts

Assembly

1. Arrange in star pattern

2. Cap with clear circle

3. Add inner leaves

Closeup

1. Assemble the six 2 1/2" clear strips into a six-pointed star.
2. Place the clear circle over the center of the six strips. Secure with fusing glue.
3. Form inner leaves. Place two 3/4" strips on each snowflake arm about 1" from the center. One end should rest upon the arm, and the other on the kiln shelf. Secure with fusing glue.

4. Add outer leaves

5. Add green circles

6. Add green chips

Closeup

4. Using the 1" strips, assemble outer leaves. Secure with fusing glue.
5. Place one green circle onto the end of each arm of the snowflake.
6. Accent each inner leaf with a green chip (saved corner of squares). Place a small drop of fusing glue, and then a green chip on the end of each inner leaf.

Fusing

Place the snowflake into the kiln, and fuse at 1465^oF for 5 minutes. Anneal for 20 minutes at 960^oF. Flash cooling (crashing the kiln) is not necessary.

Finished Snowflake

Snowflake

Snowflake

Fusing Glass

Introduction

Let's face it, I'm obsessed with glass. I've made stained glass for years, and I built miniature studio in my garage so I can make torch-worked sculptors.

Fusing, and slumping is one of the few glass art forms I haven't yet tried.

Having no previous experience in fusing, I decided to take a class at the Bay Area Glass Institute (BAGI):

What is Glass Fusing?

Fusing is the process of heating multiple pieces of glass in a kiln to form one unified piece. Heating the glass just enough to join, but while still retaining the original shape of the individual pieces is called a tack fuse. Heating the glass enough to form one seamless piece is called a full fuse

What is Glass Slumping?

Slumping describes the processing of reshaping a piece of glass by heating it, and allowing it to fall into a mold (form).

Instructor

My instructor, Janett, has an amazing knowledge of not only glass fusing, but also torch working, glass blowing, and stained glass:

Tools

Here's the tools of the trade:

Bullseye glass

Kiln

Glass cutter

Fusing glue

Not all glass is appropriate for fusing. Glasses which expand, and contract at different rates will indeed fuse, but then crack as they cool. Bulseye glass is the most popular as it comes in a wide variety of colors, and styles.

Kilns are basically big ovens which can reach about 1600^o

Glass cutters are used to create scores, and direct glass to crack along certain lines.

Fusing glue hold the glass in place before it is fired.

Kiln shelf

Kiln wash

Applying kiln wash

Fusing is typically done on a large flat unfinished ceramic kiln shelf.

Kiln wash is basically glass Teflon. It keeps the glass from sticking to the shelf.

First Project

Glass fusing is deceptively simple: Cut out pieces of glass, arrange them, and pop them into the kiln. Here's my first project:

Red circle of glass	Cut-up circle of glass	Into the kiln
Fused circle

But there are any number of things that can go wrong. Molten glass flows -- sometimes in unpredictable ways. Fire too long, and the glass will spread out, and then contracts back leaving uneven borders. Fire too short, and you'll get lumpy glass. Some glasses melt faster, and spread out when fired; others tend to stay put. And many types of glass don't fire true -- i.e. change color when fired. To help out us neophytes, Janett created this pallet of pre- and post-fired glass:

Second Project

Here's my second project. On the bottom is a layer of clear glass. The second layer has red on the edges, stripes of black, and more clear in the center. On top of that is amber squares, and sparkling green stringers (thin rods of glass).

Before fusing

Fused, and slumped

Julie's Projects

Here's a few projects made by my classmate Julie. The piece below is made of three layers of glass, giving it great depth. Some of the squares almost appear to float.



Here's very simple, but elegant design:

Big Tools

One of the cool things about BAGI is their equipment. I grew up with a garage full of lathes, acetylene welder, and drill presses, so I found BAGI's collection of over-sized glass grinders fascinating:

Belt grinder

Bench grinder

Disk grinder

Holiday Sale Items

BAGI is a nonprofit organization, and every year they have a Holiday Sale. Artists donate pieces, and the proceeds go to BAGI. These are amazing. I guess it's always good to have something to work up to ...

Holiday Sale

Holiday Sale

Holiday Sale

Holiday Sale

Conclusion

I've seen a lot of fused glass at art shows -- much of it monumentally bad. From this I assumed any yo-yo could fuse. But it's more complex than I expected. There's a lot of technical gobbly guck: coefficient of expansion, annealing/fusing/tacking temperatures, devitrification. There are four types of clear glaze that melts at different temperatures. There's dozens of types of glass: transparent, opaque, streaky, iridecent, textured, dichroic, two types of black, and 19 types of clear!

But it's not that hard either, and it is great fun.

LED Christmas Lights

LED Christmas Lights

Recently I bought a set of LED Christmas lights from All Electronics:



These lights are sold as-is because the controlling units overheats. So why buy a known-defective set of Christmas lights? To fix them, of course! These lights are controlled by a programmable chip called a PIC. Careful programming can significantly reduce the power consumption, and fix the heat problem.

What is a PIC?

A PIC is essentially a one-chip computer designed for embedded systems. You can't play video games on it, or even run Windows. It's made to run very simple tasks. A typical PIC only has a few hundred bytes of RAM.

Replacement PIC

The PIC that comes with the LED lights is a write-once device. It can't be modified. Fortunately there are a number of programmable replacements. I choose the PIC16F627a, mostly because I already had several on hand. They're available at mouser.com. for about $1.75.

Original: PIC16C54 (CF745)

New: PIC16F627a

Tools

Writing code into a PIC requires a programmer. Removing the original PIC part requires a soldering iron, and a solder sucker (remover).

Warp 13 PIC Programmer

Soldering Iron

Solder Sucker

Adding a Socket

The LED controller comes with a 18-pin DIP (through-hole) PIC soldered directly into the PC board:


To ease development it is best to remove the original part, and install a socket:

Desolder PIC

PIC chip removed

Socket

Hardware Programming Model

Eight bits (signals) are used to control LED illumination. Four bits are used to select each LED color (red, yellow, orange, and green). Four bits are used to select a bar or arm of the star (e.g. all LEDs on the horizontal axis correspond to bar 3):

An LED will illuminate if both of its bar and, color are selected. Thus, selecting red, and bar 1 will light the two LEDs on the vertical axis:


The following diagram shows the control signal to PIC mappings:

Software

Originally I had hoped to read the software from the original PIC, and then modify it for my purposes. But the PIC16C54 is an unusual part, and my programmer can't read it. So I decided to write everything from scratch.

Pulse Width Modulation

This code uses one of the PICs timers to create pulse width modulated signals. To prevent the unit from overheating the power consumption must significantly reduced. A common trick to reduce the brightness of an LED is pulse width modulation (PWM). Basically this means turning the LED on and off very rapidly -- so quickly it is undetectible to the naked eye.

The brightness, and power consumption are adjusted by changing the duty cycle (percentage of time spent on).

Algorithm

Here's a highly simplified version of the code, written in 'C':

pseudo_code.c

Source Code

Here's the real assembly code:

xmas.asm

Conclusions

The power reduction was a success. The lights used to draw a maximum of about 1.8 amps; now it's down to about 430 milliamps. It doesn't get warm even after hours of operation.

Writting display patterns is pretty easy. But because of the limitations in the hardware, there just aren't that many interesting designs you can create.

Here's a video of the lights in action (4MB):

xmas.avi