Mica shift – to slice or not to slice
Mica shift techniques add a sense of depth and dimension to your polymer clay projects. The reflective nature of the mica particles creates a twinkling, three-dimensional effect reminiscent of Tiger’s eye and Hawk’s eye gemstones. The results can be applied to virtually any type of decorative crafting. Mica shift is well suited for jewelry projects such as pendants, barrettes, earrings and key chains. It can also be used to add pizzazz to boxes, business card holders, vases, candle holders and compact mirrors.
The mica shift effect is achieved by manipulating the mica particles that are present in metallic polymer clay. These particles have a dull side and a shiny side. The clay is first thoroughly conditioned so that all the particles become aligned. When a textured pattern is impressed into the clay, the mica particles are pushed down so that they surround the pattern. The resulting raised areas are then carefully removed, leaving a smooth surface. The manipulated mica particles remain below the surface, and reflect light differently than the surrounding surface clay. After curing and finishing, this creates a deep, 3-dimensional image which is smooth to the touch. This effect is sometimes also called a ghost image.
Please note that because glitter is shiny on both sides, glitter clays – while fun in their own right – will not work for this technique. Pay particular attention while you are shopping for your clay, especially if you are choosing Sculpey’s new line of Premo! Accents. The glitter clays in this line are beautiful, with glitter particles that are very small, and can be easily mistaken for the mica in metallic polymer clay. The projects pictured on this page were made using Premo! Sculpey in metallic colors. In addition to having an abundant mica concentration, Premo! is strong after baking while still retaining some flexibility. This is important during the finishing steps of the process when you will be sanding and handling the piece rather extensively.
Although often regarded as an advanced technique and even something a little mysterious, once the basic concepts are understood, mica shift is fun and easy. In this tutorial we’ll walk you through the steps and describe different approaches to creating interesting mica shift pieces.
If you are brand new to working with clay, you might want to read our introductory article Getting Ready to Work with Polymer Clay for an overview of basic techniques and the tools needed to be successful.
What you’ll need
- Premo! Sculpey metallic clay in your choice of color
- rubber stamp or texture sheet
- pasta machine for conditioning
- acrylic rod for hand-smoothing
- clean, sharp tissue blade
- baby wipes, alcohol wipes, or a cleaning cloth of your choice
- baking tile and work tile with non-slip mat underneath
- polymer clay oven and thermometer
- wet-dry sandpaper (400, 600, 800, 1000 and 2,000 grit)
- a piece of soft denim and piece of flannel for buffing
- Pledge Floor Finish with Future
Preparing your clay
The first step in creating mica shift is the proper conditioning of the clay. In addition to the usual purpose of making your clay pliable and easier to work with, it is during conditioning that the mica particles are aligned. A rolling device is necessary for this step. A pasta machine is recommended, but you can of course use an acrylic roller or similar tool if that is your preferred method. After slicing your clay from the block, begin working it by hand until it is slightly thicker than the widest setting on your pasta machine. You then begin the process of feeding the clay through the rollers, folding it, and feeding it through again. And again….. Always be sure to place the folded edge against the rollers to avoid trapping air and creating bubbles.
It is critical that you consistently feed the clay into the machine in the same direction. The rolling is pulling the mica into alignment, and accidentally changing direction will undo your hard work! Watch your clay to monitor the progress. It will progressively become shinier. The edges will become smoother. Your goal is a smooth, shiny, streak-free piece of clay of uniform thickness. This may take several repetitions, commonly 20 or more. You may wish to progress through a few thinner settings on your machine, but keep in mind that you will be removing the raised surface of your clay, plus sanding through several progressive grits of paper. Be sure to leave an adequate thickness of clay to work with throughout your finishing steps.
Make a good impression
Once your clay is properly conditioned, it is time to manipulate some mica! If you began this project using a large work tile, now is a good time to move your clay onto your baking tile. Whether you have chosen a rubber stamp or texture sheet, be sure that it is clean and free of debris. Most all rubber stamps or texture sheets can be used, giving you a wealth of choices borrowed from the stamping hobby. The deeper the stamp, the more drastic the effect, but the method also works well with a shallow stamp. When using a texture sheet, you have the added option of laying the sheet on top of the clay and running it through your pasta machine to make the impression. Regardless of your method, be sure to apply consistent, even pressure so that your impression has a uniform depth. Avoid rocking back and forth if you are using a traditional stamp.
Get in shape
Using your clean sharp tissue blade, carefully cut to shape the perimeter of the piece. Have fun and use your imagination. If you like a basic square, think about curving your lines inward or outward for something a little different. The shape can be anything you want it to be. This can be a bonus particularly if a portion of your design doesn’t suit you. Simply cut it off!
Time to chill
During all of the conditioning and working, it is likely that your clay has become warm and perhaps too soft for the next step. Before you begin slicing away the surface, the clay will need to cool down and rest. Simply leaving it alone, or if your work area is warm, putting it in the refrigerator for a while will give it time to firm back up a bit. Slicing warm soft clay is difficult because it can stretch and be more or less dragged along with the blade. A sharp, clean cut is absolutely necessary in order to obtain good results.
Slicing with a curved blade
Impressing your image or pattern will result in raised areas on your clay surface. In the next step of the process you will carefully slice away the raised areas. Leave the piece on your flat surface and use a thin, flexible tissue blade. Bend the blade into a curve and very carefully slice off the high portions. Cut only as deep as the recesses left by your impression. Best results will be achieved by working slowly, pulling the blade toward you, and removing just a little clay at a time. A clean blade is necessary, and it may be helpful to wipe your blade after each slice. The object is to have a perfectly smooth piece with no high spots remaining and no deep gouges. Use caution, as the tissue blade is extremely sharp. The good thing about working with polymer clay is that if you’re not happy with your results, you can simply start over. Your clay will be recycled rather than wasted, and there is nothing wrong with practice!
Slicing with a straight blade
An alternative to curving your blade is to curve your work surface instead. Simply lay your impressed clay on a clean, smooth, curved surface. A glass jar, a retired coffee mug or a vase are some good options. In this method, you will be able to slice off the raised areas while keeping your blade straight. This way, it is less likely that you will accidentally gouge too deeply into your design. When you are finished slicing, use care in removing your clay and repositioning it onto your baking tile, so that you don’t squash or stretch your design.
Smoothing the new surface
Regardless of which method you chose to slice your design , the surface of your clay will now need to be somewhat flattened. It is possible to run it back through the pasta machine, however, this is very likely to stretch and distort your design. It is preferable to gently flatten your clay with an acrylic rod.
No surface slicing – a different approach altogether
A variation of the method described above is to bake the clay immediately after impressing, doing no slicing or cutting except to shape the perimeter edges. This is an excellent alternative when using a shallow stamp, or if you simply are not comfortable working with a sharp blade on your raw clay design. In this method, your clay is cured (baked) with the raised areas intact. After your clay has cooled, the raised areas are then removed by progressively working through finer grits of wet-sanding. Although this alternative makes for significantly more work sanding, provided you have made an adequate impression, there is no opportunity to damage your design by slicing too deeply. You will be pleasantly surprised with the superior results. The tiniest curves and lines will appear so sharply, you will be amazed. Even with shallow stamping, the detail will just explode!
Time to bake
The clay is now ready to be baked following the manufacturer’s directions. Place your baking tile and thermometer inside the oven. Be sure to use your clay oven in a ventilated area. Monitor the temperature throughout and be prepared to make adjustments if necessary. Allow the oven and its contents to cool thoroughly before handling.
At this point, your clay has been baked, cooled and is ready for more handling. Whether you made your impression with a stamp or texture sheet, sliced with a curved or straight blade, or did no surface slicing at all, the next step is to sand the surface.
What may come to mind is an image of brown sandpaper used for smoothing a wood surface. This type of sandpaper is too coarse for our purposes when finishing a polymer clay mica shift project. We will be using wet/dry sandpaper, which has a grayish black color. It is commonly used in the automotive industry for body work and painting. It comes in various grits. For our projects we are using 400, 600, 800, 1000 and 2000. You will likely find 400 and 600 grit readily available at your local Home Depot. For the finer grits, you should be able to find them at an auto parts store, or the auto parts area at Walmart.
As you may have guessed, we will be wet-sanding and of course, water is necessary. An efficient way to set up your work area is to use a table and comfortable chair. On the table you can spread a towel or other absorbent material. Use a few drops of any liquid soap in warm water and fill your flat dish to about an inch deep. Cut or tear your sandpaper to a size that is comfortable for you to work with. Ideally, it should fit into your soapy water dish. And remember, if you’ve borrowed a dish from the kitchen, you should keep it with your clay supplies from now on, and not re-use it for food.
Submerge your sandpaper, starting with 400 grit. Remove it from the soapy water and begin using it to rub the surface of your clay piece. Work in a circular motion, covering the entire area. The amount of sanding time necessary depends on the nature of your clay. If it is a design which you have cured after slicing off the raised areas, you will likely find that it doesn’t take very long to obtain a smooth, even feel. If your design was created without any surface slicing at all, there is significantly more sanding necessary to remove the raised areas.
In either case, as you work with the sandpaper it will trap the surface particles that you’ve removed from your clay. Dip the sandpaper into your soapy water often to rinse away the residue. You may also find it beneficial to clean your clay piece in the same way, as it too will collect some residue. The best tool for gauging your progress is your finger. Feel for uneven high spots and do your best to sand them down to create an even surface. The best time to smooth the sides and back of your piece is while you are working with 400 grit paper. It has more ‘tooth’ and will remove surface clay more efficiently than the finer grits. You may notice that your soapy water has become tinted with the color of your clay. This is normal, and it confirms that you are indeed removing surface particles from your clay. When you are satisfied with the look and feel of your clay after your first sanding pass, it is time to progress through the finer grits of sandpaper. Empty your dish, rinse it and refill with fresh soapy water before you move on to 600 grit. As you progress through the finer grits, you will be removing smaller amounts of clay and your water will not need to be changed as often.
After all of your sanding work is complete, the deep 3-D effect will be much more evident in your clay piece. You may wish to hand buff your design with some soft denim. An old worn-out pair of jeans is perfect to use. After using the denim, you can follow with a piece of soft flannel. Although sanding your clay created a smooth surface, if you rub the back of your finger over your design, you will still feel an increase in the smoothness and less ‘drag’ after buffing it. You may also notice a bit more twinkle coming from within your design, but wait, there’s more!
You may have noticed that your design looked sharper while your clay had water on it. Imagine your favorite picture being framed behind glass that has become cloudy. It would likely be difficult to see the fine detail. The same holds true for your mica shift design. Although it has not exactly become cloudy, it has not yet been treated to become crystal clear. An easy, inexpensive way to give your design the clarity it deserves is to apply a coat of Pledge Floor Finish with Future. Be sure there is no dust or debris on your clay, and simply paint it on with a clean brush. It will air dry within 20-30 minutes. You will be amazed at the way your design will pop! You will appreciate the depth of your design as you look at your clay piece from different angles. The detail will be sharp and crisp, and the sparkling reflection of the mica particles will leave you with a delightful sense of accomplishment!