PMC3 and Dichroic Glass

So you want to use dichroic glass with your silver clay OR you want to use silver clay with your Dichroic Glass? The specifics here will pertain to PMC3(tm) but if you use Art Clay Silver(tm) you can adjust the firing schedule accordingly; the process is the same. PMC3 however, is designed especially for use with glass. It fires at a lower temperature than that used to full fuse glass so your stones will stay the way there were when you started.

I am a Senior Instructor with PMC Connections and a PMC certified instructor with the PMC Guild, please click here for my class schedule. I also sell PMC and related supplies.

Using PMC3 and Dichroic Glass is simple. 

1. You can either make or buy some small dichroic glass 'stones'.
2. There are several ways that you can 'set' dichroic glass in place with PMC3.
   1. You can use the original 'safety circle' method in which you make a coil and wrap it around the entire stone.
   2. You can use a slab and build your piece around the stone.
   3. You can make a coil or small slab and attach it to only part of the stone, leaving much of it floating freely. (will be added soon)
   4. Lastly, you can set your glass piece after firing using prongs or other mechanical mechanisms (we won't cover this method here.)

The Safety Circle Method:

This is the original method I learned for setting dichroic glass in PMC. It involves wrapping a coil lightly all around the 'stone'.

1. Make a bezel by making a coil out of silver clay and wrap it all the way around the stone. Don't wrap it tightly but it should touch all around, just enough to hold the stone as it will shrink, grabbing the stone as it does. You can then either add a loop on the top for a bail OR you can add more shapes around the piece to make it more elaborate. Most people don't put clay on the back side of the glass but leave it open. This uses less clay and lets light shine though the glass. There can also be cracking issues with totally enclosing the glass back.
2. After the piece is dry you should fine tune it in the green ware state, file any unwanted, uneven edges etc.... then fire using the schedule below. I do NOT crash cool* my pieces when I mix glass and metal. Crash cooling can introduce undue stress on the pieces causing the glass to crack. Glass and metal have different rates of expansion and contraction as they heat and cool. If one material expands or contracts more quickly than the other it is only natural that it will pull apart from the other OR if it can't then it will cause the weaker part to crack or tear.
3. NOTES:
   1. Wear safety glasses when you look into the kiln for two reasons: 1] Cold air rushing over your pieces can cause thermal shock and your pieces may break. There is really only one place for the shattering glass to go and that is towards YOU! 2] If you are going to look into the kiln a lot you will need to purchase special glasses to protect your eyes from the harmful effects of the heating elements. 3] If you wear contacts and get too close to the kiln you may melt or damage them ... OR your eyeballs!!     
   2. Some discoloration may occur around the stone; if you use a light color you may see a yellowish color at the edges. This is caused by a chemical reaction between the glass and the silver. You can use Crystal Clear art glass as your top piece when making your own dichroic glass stones to avoid this discoloration. Crystal Clear is chemically altered to avoid this reaction.

   

   This piece was made using the safety circle method with some added decorative elements. The bail was made using one end of the coil. (c)2004 Nancy Tang Glass Orchids

The Slab Method:

This method is similar to the one used to make a foldover pendant.

1. Roll out a small slab of clay about 3 cards thick. This slab should be large enough to allow you to place the stone on it and leave space around all sides. You will need more space at the top of the slab to make the fold just like for a foldover pendant.  Rule of thumb - leave 1/3 of the slab at the top for the fold.
2. Center the stone on the bottom 2/3rds of the slab. Either press it in a little so that it leaves it's shape on the slab OR outline it with a pencil. Remove the stone. Cut out a space that is just a little smaller than the stone. Save that little bit of clay for something else <smile>. Put the stone back in place over the whole.
3. Using a straw, create your foldover bail (simply fold the top of the slab over the straw and use a little paste and push to stick it to the front. Your design elements will cover the stone edges and can extend over the folded over parts as well. I feel that this creates a more cohesive and interesting piece.
4. Using coils, molded shapes, textured slabs etc.... cover the edges of the stone so that it is held in place. This is a sort of bezel. You can cover the edges entirely or leave spaces open like prongs.
5. Make sure you press the 'bezel' pieces so that they are sure to hold onto the stone. They will shrink and the glass will flow a little so everything will tighten up when you fire the piece.
6. Dry your piece fully and clean it up in the green ware state.
7. Fire to 1400 degrees for 10 minutes. I fire these pieces to 1400 so that the glass will start to flow a little which will actually fuse the metal and glass together a little. You can probably get away with a lower temperature but this is what makes me comfortable. Remember that there is a hole behind the glass in the pendant that will let the light shine through.

The pendant above was made using the slab/foldover method. Also shown are a matching clasp set. They haven't been colored with patina yet in this picture. The stones on the clasp are set on a solid base using a coil all the way around. (c)2004 Nancy Tang/Glass Orchids

Firing schedule for PMC3:

1290 for 10 min

1200 for 20 min

1110 for 30 min

*Crash Cooling: opening the kiln door once the piece has finished firing and leaving it open till the internal temp is 900. Opening and closing the door until the temp does not continue to rise over 900 degrees. Then closing till fully cooled. This is done for several reasons: 1] To speed up the cooling process. 2] To reduce the chances of devitrification (a pitting or marring of the glass surface caused by the growth of crystals in the glass surface. This usually happens between 1300 & 1400 degrees. However, Bullseye art glass (which is the most common fusing glass) is specifically designed to avoid devit. and this is not a common problem in my experience.

**I will post images of the steps involved as soon as I can.