Friday, April 27, 2012

Artist’s Journal: Enameling & PMC

by Yvonne Yao

Editor's note: Since Yvonne is starting to experiment with PMC and enamel, we asked PMCC Senior Instructor Teva Chaffin to add her thoughts to Yvonne's journal. Teva's comments are italicized.

I’ve recently started enameling again and it has reignited my desire to learn how to simplify the cloisonné and plique-a-jour framework process by using PMC and PMC syringe. So today, I decided to go back to the basics and both review what I have learned, as well as try out a few new techniques.

Since I do not have my own kiln, I decided to work with what I have. With a butane torch and kiln shelf, I began to torch fire my own PMC pieces. I also wanted to try rehydrating my old hardened clay and review how to gypsy-set a stone in wet clay. Lastly, I needed to test and find out how thin I can make my plique-a-jour frameworks and still apply the enameling techniques without warping the piece throughout the additional heating process.

First step: re-hydrating my old clay. I originally learned to do this by laboriously filing down the hardened lumps into powder, then slowly adding water to bring the clay back to a sculptural consistency. However, the filing part was so time consuming that the process felt like a waste of time. Therefore, I did a little more research online and learned that by putting the cay in a ziplock bag with water and pressing out the air, I can rehydrate the clay by just letting it sit. Simple absorption will do the rest. This did not work out for me as I expected, the clay remained hard to the touch. But I did find that it softened the old clay enough within the core that I was able to file faster and easier due to the creamy texture.

With the newly rehydrated clay, I rolled out a sheet three cards thick and cut out a design to start texturing. I gypsy-set my row of CZ’s and cut out a shape in the piece to test my plique-a-jour. Then I syringed a small scale design onto the panel to test out a shallow cloisonné. Next, I drew an organic pattern of a leaf on a sheet protector, let it dry, and peeled the shape off to fire and test to see if I can create a plique-a-jour design in a framework that is as thin as it is-straight from the syringe nozzle (no backing and no thickened and equally balanced cells -just a raw and roughly drawn organic shape).

I stored the syringe for future use in distilled water and turned my attention to firing. I set up my fire brick and kiln shelf on a stool and torch fired each piece for 1-1.5 minutes. The pieces turned out beautifully. For best results, fired PMC should be tumbled for up to two hours before enameling. This helps pack down the porous silver and make the piece nice and dense so that the enamel will sit on top of the silver surfaces and give off a beautiful clean color. I tumbled my pieces and set off for my enameling workshop. The results are below. I was excited to find that PMC syringe made for a wonderful-quick and easy-solution to creating sterling silver frames for small plique-a-jour work.

My observations:
1) I chose to use very thin syringe extrusions to create my framework. This did not cause warping of the frame during firing, did it make enameling with capillary action more difficult.

2) The rounded edge of the syringe framework (instead of a flat edge that is created by sawing it out of metal sheet) made it more difficult to fill each compartment and increased the chances of the enamel pulling back between firing.

Teva: Your plique-a-jour framework of the leaf is so cute. Of course I love leaves and trees! Years ago I came across a square syringe tip. I wonder if using it would eliminate the challenge that the rounded edge of the syringe work posed. I have found that it is challenging to apply square PMC syringe without twisting the flow thus distorting the square.

3) The variance in size between the smallest compartments in the leaf design to the largest made it difficult to distribute and fire all compartments in the design for an even and clear color on the enamel without multiple turns of patching. Thus, I will have to continue to experiment with the design itself to get a better result.

4) As for the cz studded PMC piece, wet packing on it worked beautifully. Some of the colors did not turn out as I had expected, but the stones did not change color through multiple firings.

Teva: In my enameling and PMC adventures I have learned that by applying a first layer of flux for silver helps to eliminate color distortions. Also when using a easy to over-fire color such as pink, red or orange in a piece, I use flux (for silver) in that space until the last firing at which I use the color. This prevents the over-firing of those particular colors.

By doming your 3 card thick cloisonné piece you lessened the need to counter-enamel. You stated that the CZ’s did not change colors with multi-firings so I am just curious how many firings (or layers of enamel) you applied to this piece. I am usually limited to 2-3 very thin layers of enamel on a domed piece of PMC with a 4-5 card thickness without having to counter-enamel. 

I highly recommend to everyone to make test plates of their enamels. I do this by rolling a slab of 3-cards thickness, cutting in a rectangle size of 2” x 1.25”. I fire these at 1650 degrees for 1 hour.  After firing, I tumble for approximately 2 hours. I do counter-enamel my test plates and use flux for silver on the front side as the first layer. For my second firing, I apply a counter-enamel on the back and a dot of each color on the front. I keep a chart of each test plate so that I can reference it for my selection of colors I may want to use on future PMC pieces. Oh yes, be sure to use a sharpie to record test plate number on the actual test plate. 

Excellent article Yvonne. Thank you so much for sharing your adventures with us.


Janet Alexander said...

Yvonne, thanks for sharing! I found it very interesting! Can you try filing the rounded edges with small needle files?

Kathy C. said...

I'm a big fan of enamelling and am in awe of what a big set of projects you set out for yourself! You got great results, too. What is gypsy setting? I'm not familiar with this term?
Thanks for the interesting read and the comments.

Roxanne said...

Thanks for sharing this. I have worked with PMC but never enameled. I have all the stuff I need to try it, so it's on my to do list. There was someone who gave a lecture at the PMC guild conference in 2006 on doing plique a jour with PMC paper. It would be more work because you'd have to do all the joins, but you would have vertical sides.

Yvonne Yao said...

Teva: Thank you for your helpful thoughts and advice! It's a rough estimate, but I fired the domed piece of my PMC design in the smaller kiln (1500) about a total of 5-6 times.

Janet Alexander: I had so liked the organic delicacy of the leaf frame created with the syringe that I hadn't wanted to touch it (for fear it'll break, and because I wanted to find the fastest way to make a plique-a-jour framework without additional touchups). However, I think you're right, slightly filing the inside edge of the PMC piece after the initial firing and before it is tumbled might be worth the extra time. Will give it a try-thanks!

Kathy C.: Thanks Kathy! Allowing myself to experiment freely with PMC has been a wonderful release from the meticulous detailing I do on a regular basis with my jewelry. In regards to your question: gypsy setting a stone is also known as "flush-setting." This is a technique of stone setting where the stone is secured by recessing it into a hole that is drilled into the ring, instead of using prongs or a bezel.

Roxanne: I have never heard of PMC paper-will have to google it! I definitely encourage you to jump in and try plique-a-jour, especially if you already have all the materials and gear on hand! I really enjoy the technique, even though it can be rather tedious at times. I have been trying to find ways to make the framework process more concise in order to see if the technique can be used for consumer designs without driving up the cost of time & labor in the competitive market.