A couple of months ago, I received a custom order for cobalt blue dinner plates. The customer was great and very patient as she had waited years to get these custom plates made exactly as she had dreamt. The task for me was to figure out how to accomplish her dreams.
The first decision was color and it ended up being a decision of glass. I am mostly a Bullseye fused glass person, but this time the Spectrum cobalt blue transparent color matched her ideal, so I went with Spectrum for his project.
The second challenge was how to make the ruffles. Often when making a glass plate, you use two sheets of 1/8″ glass in order to get a nice even 1/4″ glass plate. See my previous post on glass thickness, Do the Math – Fused Glass Likes 6mm or 1/4″. And often one of the two glass sheets is clear as it helps fuse the other colors without changing their colors and let’s be honest, it is cheaper than other glass colors. Typically to get a ruffle you do a contour fuse (1380 degrees F in my kiln). However, if I used clear glass as the bottom layer and cobalt blue on top, you would see a clear gap between the blue ruffles not to mention a clear rectangle in the center. So instead, I used blue for both layers of glass.
The last challenge was the shape of the final plate. She chose a rectangular plate and wanted the outside ruffle to be 1.5″ deep and then the drop of the center of the plate to be .5″ deep. I called/wrote every mold manufacturer I could find and no one had a mold that shape nor made custom molds. I am quite sure there is a company out there that would make the custom mold, but I didn’t want to spend a fortune for one set of dinner plates.
I investigated Duraboard and decided that this was perhaps my best option but it was very expensive and I was nervous about spending the money on something about which I didn’t know that much. In addition, in order to get the .5″ drop, I would need to get a deeper board and then carve the bottom and make sure it was level. I called D&L Art Glass and talked with my favorite sales person, Beverly, and while she said Duraboard would work for my application, why not try several layers of fiber cloth which I already had and with which I could experiment. She was absolutely right!
I stacked three layers of 1/8″ fiber, cut the inside rectangle out and slumped the first plate. It was perfect for my goal and gave me the exact shape I wanted. However, I had forgotten about making sure to burn off the fiber and it left a haze on the plate. The next couple of plates I vented the kiln until it reached about 1000 degrees, but then stopped on subsequent plates and they were fine. So I believe you really only have to do it until you completely burn off the fiber. Since I was using it for slumping to 1235 degrees, it took me several firings to completely burn things off. It would have been better if I had just burned it off on its own by taking it to a higher temperature. Hindsight!
I was a great project with many challenges and wonderful lessons learned. And I ended up with a very happy customer who saw her dreams come true!
Here are my key lessons learned:
1) Make sure you burn off fiber before you use it or vent the kiln if it has not been allowed to burn off.
2) I was only able to get three firings on the Spectrum Cobalt blue glass. If I did a fourth firing to correct issues, I ended up with lots of small holes in the bottom. In my experience with Bullseye, I can get more like 5 firings before weird things happen with the glass.
Have you ever needed to make a custom mold? What material did you use? I would be very curious to learn more for my next project. Thanks!