How To Play With Slate

I suggest slate to all aspiring rock sculptors. It is an excellent material for learning to sculpt. It is easily worked with hand tools and responds well to electric or air tools.

In California, slate is plentiful. It is fairly easy to drive to a slate outcropping and harvest a few pieces. There are rules and proceedures for collecting on various types of public lands. If you are unfamiliar with the geology in the area you reside, I suggest that you join a rock club. There are active rock clubs somewhere near you if you live in the USA. I assume the rest of the globe we reside upon has similar clubs.

First put on sturdy gloves. Slate has very sharp edges. Take the piece of slate in both hands and attempt, just using your own strength, to break it. If the slate is a thick piece, you may want to cleave it into multiple pieces. To do this, take a dull thin knife and place it parallel to the groove. Holding the knife firmly, hit the knife solidly with a hammer. The slate should break with a fairly smooth flat surface. It is because of this quality that I recommend this material to beginners. Natural flat surfaces are rare. Usually, relief sculpture material requires a saw to achieve this result of a flat surface. A piece of slate 3/4" thick is good to begin with. How large a piece you use depends on you and your pattern. If you are doing a large piece of 50 to 100 lbs, you may want to have a 1 & 1/2" thickness. I suggest begining with a piece 6" to 12" on a side.

I provide a whole bunch of patterns you may copy, or you may draw your own. To use one of mine, go to Animal Patterns and select and print out a pattern. If you wish to use a different size of the pattern, hold your mouse arrow over the animal pattern and right click. On the menu that appears, left click on 'Save Image As'. Choose a file to save it in and then open the file in any picture editor. Follow the instructions of the program you choose to use for the resizing of images.

With a pattern chosen and your slate prepared, you are ready to create a work of art. There are three basic steps that I follow. I will explain these as clearly as I can.

#1. Applying the Pattern to the Slate. This can be accomplished in several ways. Here are the two simplest.

The first is to glue the cut out of what you have chosen to sculpt to the slate upon which you will be working. This can be done with a variety of adhesives. When choosing a glue, always consider what chemicals are used in its manufacture and the effects these chemicals will have on you and the environment you inhabit. I find that liquid paper or wood glue works well as long as I allow it time to cure. There are a couple of problems with gluing your pattern to the slate. The first is to not rub out the lines on the glued paper. Slate is a visibly dirty material. As it is transformed into dust, it coats everything around with a fine black powder. The best way to preserve the lines of your glued paper pattern is to blow gently through a straw across the paper pattern. The second problem with gluing your pattern to the slate is that there is a cleaning chore added to the final finishing step. Glue may seep into a crack or fill a pockmark. You may accidentally smear or spot with glue an area on the slate that you had wanted to leave natural for the contrast value. Mostly the glue is easy to clean up. It usually only becomes a bad problem when it is in a visible part of your finished sculpture. If it does not add to the sculpture, it must be removed. Depending on the severity of the glue contamination, the sculpture must be changed. You, as the artist, must make the observation and the choice.

A second way of transfering a pattern to the piece of slate is to make your pattern sturdier. The easiest way to accomplish this result is to glue the pattern to stiff cardboard and then cut it out. This strengthened paper pattern can last through several sculptures. To use, you hold the cut out pattern firmly in place on your piece of slate and draw around it with a colour of pencil that is clearly visible on the slate. The patterns I provide have dots where pivot points are for the head, tail, legs, ears, horns, fins and wings. As long as you match the dots to the appropriate pieces, it is easy to check your progress and fine tune your sculpture as you go through the various steps from twinkle-in-the-eye to gleaming-on-the-shelf.

#2. Creating a Sculpture.

Here is where tools become important. Misunderstanding tools is the largest obstacle an emerging sculptor has to overcome. It is not the tool which creates a work of art. It is a thinking, feeling individual. In a word, You.

Tools cost money. Material costs money. If you are wealthy, you can pick up the latest catalogue and have everything in it delivered to your door. This is not as great of an advantage as it may seem. I know lots of people with lots of nice tools who do not do much of anything with them except trot them out to show them off. Having tools does not automatically bestow ability to use them upon the user.

A tool is anything that will scratch your rock. I have found that the more simple the tool, the easier it is to master the technique I am about to describe.

You have your piece of slate with a pattern glued or drawn in place and are ready to create a magnificent work of art. Get a 3" drywall screw. Actually, any size of drywall screw that can be easily grasped is good. Wrap tape or cloth around the threads of the screw where it comes into contact with your fingers. I use duct tape. A nail will work, as will a regular screw. What is better about the drywall screw is the angle and sharpness of the head.

Slate is very fragile. It breaks in tiny little flakes as well as large sheets. Hold your screw as you would hold a pencil. Press the point firmly at the outline of your pattern and lightly etch a line all the way around it. Trace around your pattern several times, to really etch a visible outline, taking care to not press so hard that you flake slate away from the pattern itself. When you have reached a depth of 1/8", turn the screw around and place the sharp part of the head of the screw into the groove with the main part of the screw perpendicular to the groove. Very carefully pull the head of the drywall screw back towards you. A small trench will appear around your pattern. Continue this proceedure until you have removed material to the depth of 1/4" and a 1/2" width all around your pattern. With this proceedure done, you may now begin on the actual sculpture. Take the point of the drywall screw and lightly but firmly make an outline around the legs or wings of your pattern. It is these parts of the critter which will stand out most in a relief sculpture. The depths of all the other parts of your pattern are determined by the way the legs, tail, fins, wings, ears, horns or arms stand out. A very light touch is necessary and the force of this light touch is applied away from the part being outlined.

For example: You have a polar bear on an ice flow. You have completed the main outline and have just etched a line around the back leg. In order to make the tail distinguishable from the main body of the polar bear, your eye must see a slight difference in depth between the leg, the tail and the body. The differences must be believable within the 1/4" thickness of the pattern outline. You make your line around the leg 1/8" deep. You do not remove all the material surrounding the leg to that depth. With the head of your drywall screw, you lightly pull material away from the immediate area around the back leg. You then do the same with the front leg, the tail and the ear. These 4 parts are what will stand out most on this sculpture.

Now you change tools. Any thin iron-based object will work. An old file. A butter knife. Wax carving tools. Wood carving tools. Dental teeth cleaning tools. Surgical tools. A broken hacksaw blade. The world is full of discarded iron-based useful sculpting stuff.

With your hacksaw blade broken smoothly so that there is a perfect straight edge, you push lightly with a slight angle down and away from the back leg. You carefully remove material between the front and back legs, leaving a slight swell between the two. From the back leg towards the tail, you curve the material slightly down. The tail will stand out more than it should. This is a tricky part. The tail is clearly outlined. Take your drywall screw and place it against the tail so that you are pulling away from the pattern. The sharp part of the head of the drywall screw should catch in a grove in the slate. Pull sharply. The tail should break off. Beneath where the tail broke will be another perfect tail. Outline this tail lightly with the point of the drywall screw and then curve it gently outward and down with the broken hacksaw blade. Just above the tail, the back of the polar bear rises. The polar bear's back should be slightly more raised than the tail and slightly less raised than the leg. From the front leg to the head, remove slate with the hacksaw blade up to and around the ear. Be careful not to break the ear. Curve the material down towards the bottom of your 1/4" outline depth. With the drywall screw point, etch in the mouth and eye of the polar bear. You are almost done and are ready for a new tool. Take fine sandpaper or steel wool and rub the polar bear all over. Be sure to lightly sand all the edges, taking care to not remove any of the details you want to keep. You should have a wonderful piece of art. It may be a little difficult to see it. A greyish-black polar bear on a greyish-black background.

#3. The Finish.

The finish is to make your sculpture stand out more from the background. I had a lot of trouble doing that with slate. One way I tried was to scar up the slate all around what I had sculpted. This made the smoothness of the sculpture more eye-catching, but the colour difference still made a close study necessary. If you are looking for a subtle effect, this is a definite plus.

I like to see what I have wrought easily from a distance. I tried applying various waxes and liquids to the sculpted part of the slate I had worked upon. The immediate effect was quite satisfactory. The polar bear stood out bright black on a dull greyish-black background. A problem with using the waxes and liquids was that they tended to bleed into the area of slate I did not want to accent. By using sandpaper, steelwool, the hacksaw blade and the drywall screw, I was able to remove the effect of the waxes and liquids from the undesired areas. This is a lot of work and it is very easy to accidentally ruin the sculpture. Another problem with using waxes and liquids is that they soak into the slate and fade within a short period of time, requiring multiple applications. I found this to be extremely unsatisfatory.

The liquids I used were various plant and vegetable oils. The waxes I used were paraffin and carnauba wax. A problem I have noticed on sculptures I have created in various materials is that the finishing material ages. As it ages, it changes colour and sometimes cracks and sometimes flakes off. Some finishes also get gummy or sticky and thus gather a fur coat of dust. Boiled linseed oil yellows and becomes gummy and requires removal after about a year. Carnauba and paraffin waxes fade and particles of dust become embedded with each renewed application and, over time, become quite cloudy. Shellac and lacquer change colour and crack. Polyurethane coatings turn yellow.

It was while I was removing a mess of wax from the area around a dolpin that I discovered the technique for transforming a lead-coloured material into a gold-coloured material. I had removed the same area of wax several times and was getting a little bit frustrated as well as worried that if I had to do any more wax removal, my sculpture would be ruined. While pawing through various boxes of old stuff, I found a tinker-toy shaped wooden wheel with very fine brass wires jutting out from the holes. I put a 4" stove bolt through the hole in the center of the wooden wheel, with washers placed on either side to hold it tighly in place. I put this contraption in a antique electric drill and went over the portion of the background of the dolphin sculpture where I wanted the wax removed. My intention was to cause as little of the slate to disappear as possible. The drill turned very slowly and when I looked at the result, I saw gleaming gold on the slate where I had applied the wire wheel. I was sure the brass of the wheel was transferring itself to the slate. I took a fresh piece of slate and watched as it turned gold. I was very excited. I pressed hard with the wheel and the gold disappeared. I then went over where I had changed the colour on my dolphin sculpture background and watched the gold disappear there as well. Paraffin was the wax I was using at the time, so I smeared more paraffin on the slate and ran my wheel across it. The brass on the wheel turned black. Nothing but a bit of smoothing happened to the background of the sculpture. I tried speeding up the rotation of the wire wheel. I tried slowing it down. I tried various degrees of pressure. I became very frustrated. My brass brush wheel was black and getting blacker. I had not only removed all traces of the gold colour from the sculpture, but the brass brush wheel did not look at all like brass anymore. I pawed through my boxes once again looking for another tinker-toy brush. I did not find one, but the spot where I had taken the first brush from had an indentation of that brush. The indentation was a waxy yellow substance. By process of elimination, I determined the substance to be of the same colour and consistancy as a marble wax I had used on some marble sculpture. I had accidentally dropped a small chunk of this wax into the box containing the tinker-toy brass brush wheel and the wax had melted into a portion of the wires. I smeared some fresh marble wax onto the dolphin portion of my dolphin sculpture and was extremely pleased to see gold gleam back at me.

This process does not work the same for all slate. I am not sure why it works at all. I think it has to do with the pyrite content of the slate, but that is merely a guess on my part. I know that the wheel has to be turning slowly. I know that there can be no pressure applied and that there is only one direction it will work on any given piece of slate. Whatever the reason, the result is spectacular. It looks and acts as a brass coat. Over time it tarnishes, but can be easily renewed to a gleaming state.