Saturday, February 7, 2015

Mirror Clock Project Part 3 - Reverse Glass Painting

Picking out a design for the painted glass was a difficult process for me. Because I'm not making an exact copy of any specific clock, I had a lot of freedom for what I could pick for the design. The patterns used on these early clocks range from fairly simple, to extremely complex. Here are some examples of beautiful reverse painted dial glasses in several styles:

Clock 1 is very complex (lots of stencils, shading, and hand "engraving"), and it has the same look as glasses on early Aaron Willard shelf clocks. Glass 2 looks like a well made reproduction of an original pattern, complete with "engraved" gilding work in the corners, and stencil work. I especially like the third lime green Benjamin Morrill glass, with beautiful detailed acanthus leaves, and "engraved" corner flowers. The last 3 glasses use mainly simple stencils, in great combinations of colours. Most of these simple glasses use only two or three stencils.

My first sketch was a pattern loosely based on this tablet (which is unfortunately not very clear).

I simplified the pattern a bit, and coloured it in. I also made some sample colours to see which colour combination I liked best.

Red was the nicest. I liked the colours, but I found that the pattern was a bit too sparse and choppy, so I scrapped it.

It was around this time that I came across this beauty:

The original photo is quite large, and I was able to see all the small details in the tablet. I also ended up finding several variations of this tablet. One is shown below (nearly identical), and I also have one that uses browns, beige, and black, with flower decorations in the corners (the same flowers as the lime green Morrill glass above) rather than the bouquet of leaves. If you look again at the second clock in the first photo above (with the grapes) it uses the same corner leaf design as this tablet.

I thought this pattern looked quite busy, but it eventually grew on me, and I made a new sketch for it. I'm a very visual person, so I always prefer to draw myself a good "preview", especially for a complicated piece like this.

Since this is a copy of a clock from roughly 1820-1830, the glass I'm painting on is salvaged antique window glass. You will be surprised how easy it is to find ample amounts of free antique glass. I often pick up old wooden windows on garbage day, which is a great source of glass. Even if the windows are from a house built in 1920, the glass is usually still wavy, irregular, and often includes bubbles. Modern plate glass only started in roughly 1903, but wavy glass was still available for a long time after this. The house where I grew up was built in the 40s or 50s, and it had some wavy glass in the old original doors. Another source for old glass is an antiques store. One of the local places here in town keeps huge quantities of old window frames, and the owner doesn't keep the old glass. He turns these old windows into mirrors, and if I need any glass, he lets me remove whatever I like for free (as long as I'm careful). Glass shops also often replace old glass (and old mirrors), so if you ask nicely they can probably set some old glass aside for you. My local glass shop will often cut my antique salvaged glass either for free, or for a very nominal fee (1$). Since then, I've bought my own glass cutting tools.

If you plan to do a lot of projects that include glass, I strongly recommend that you NOT buy a cheap 5$ hardware store glass cutting tool. They are simply awful, and you will thank yourself later for spending a little more on a professional cutter. I bought my glass cutting tools from a stained glass shop (out of town). In general, they carry a "cheap" and an "expensive" glass cutting tool. Prices range from around 20$ to 50$ or more, and they also come with different styles of handles (pencil type, pistol grip type, etc). The "cheaper" tool uses a steel wheel, and the expensive one uses a carbide wheel. The "cheaper" tool is what I bought (by the recommendation of the stained glass shop owner), and it should last me for many years of use before the cutter head needs to be replaced. She told me that unless I plan to cut glass on a daily basis, I don't need the expensive carbide version. The tool is made with an internal oil reservoir, but she also told me that none of them at the studio use oil in their glass cutting tools, and to just use it dry. I took her advice, and I haven't had any problems.

Another very useful tool to have for glass cutting is a pair of running pliers. These are slightly curved-jawed pliers with a centre line and rubber protectors. They are used to split the glass in a clean line after you have scored the glass. At 15$, they were a great investment. The only other tool you need for glass cutting is a cork-backed metal ruler. You don't want to use a wooden one unless it's clamped or taped in place, because it WILL slide and mess up your line. Only score the glass ONCE.

Gilding on Glass

Tests were made on scraps of glass to see what method(s) would give the best results for the gilding on glass.

One of the first steps on this glass tablet was to create two thin black rings around the dial opening. This was by far the most difficult and frustrating part of the ENTIRE project. For this I used an old drafting set with an ink attachment. Thinned black paint was used, and after many tries (too thick, too thin, blobs, etc), I got the lines I needed onto the glass. To keep the centre point fixed, I simply used a Popsickle stick held in place with blue tack. My drawing served as my pattern.

The black dots in the corners are references marked on the front of the glass when installed in the door. Sometimes you will see that there is more space on 3 of the 4 sides, so this helps make sure that the pattern is centered on what will be visible when the glass is installed in the opening. The arrow points "up" (top of the tablet).

The next step is to apply the size and gilding. On this tablet, there are 4 "engraved" gilded corner decorations, and a gilded ring around the dial centre.

Once the gilding is dry, the pattern is scraped into the gold, using whatever tools work best for the job. I have seen some people use bamboo skewers, the ends of paint brushes, or metal tools such as small screw drivers. I used a combination of tools. One of them was the bottom of a paint brush, which you can see in the photo:

Add all the necessary details, and then scrape away any unwanted gold around the edges. These look time consuming and difficult, but they only took about 20 minutes each.

These corner decorations don't need to be perfect, or all the same. If you look at the original glass, you will see that they are all slightly different, and some are even crooked, or larger than others.

Stenciling and Painting on Glass

Even if this glass looks very complicated, it actually uses only 4 simple patterns. I drew mine by eye, but you could easily print out a photo and trace them. Once you have your patterns, cut them into stencils. I make my stencils from plastic folders meant for office papers. These are about 1$, and they resist strong chemicals, so they can be cleaned and reused.

The first parts of the design (the parts in the foreground) are done in gold bronzing powders. There is a leaf design at the top and bottom (centre), and the side ovals. Note that my glass is more rectangular than the original, so my oval patterns don't fall partially behind the dial ring. Mine are also less skinny than the originals.

Next, the ovals, leaves, and corner decorations are backed with black paint.

Once these are dry, the next step is to stencil the main leaves. The originals were done in a beige and cream paint, but I chose to do mine with silver bronzing powders instead. In the following photo, you can see a rough pencil sketch of the leaf placement from my drawing, but traced backwards (counter clockwise), so that they end up looking correct from the front (clockwise).

Normally, I prefer symmetry, and I'd like all the leaves to point "up", but ALL of the leaf designs on these early mirror clocks turn in a circular pattern and I have found no exceptions. I have also found that they almost always turn in a clockwise direction, so keep this in mind since you are painting in REVERSE. At this point in the painting process, a mistake usually means that you have to start over completely, since you can only remove things by scraping them off, or with solvents, which both run the risk of ruining nearby details.

Next, more leaves are added in gold bronzing powder. These tend to be random, and plentiful, so don't necessarily rely solely on your pattern. Just place them anywhere that they look good.

Picking the exact shade of reddish orange for the leaves was VERY difficult for me. I wanted something not too dark, not too light, not too bright, and not too boring. It had to closely match the original glass, but I also had to use the paints that I had available. I tried several blends of red, yellow, white, black, grey, brown, and orange, and after over 20 colour samples (only some are shown here), I ended up picking a custom shade of poppy red. The burgundy-brown background colour was actually the easiest to figure out, and that one took only 1 colour mix to get it exactly how I wanted.

Here's a better photo. Part of the problem I was having was that most of the shades of orange either looked too pink, too bright, or too red. You would think that simply adding a touch of black would solve this issue, but adding black turns the colour into a grey or brown. I spent at least a day and a half mixing colours and looking at them in different light.

A lot of these painted glasses are a mix of beautiful crisp details, and really messy, sloppy work. Try to aim for really nice crisp stencil lines (which is hard - a lot of my stencils had to be cleaned up around the edges with the tools I used for the "engraved" corner decorations), and do a slightly sloppier job with your background colours. If your glass is too perfect, it will run the risk of looking too new.

I ran into a problem with my background paint reacting with some of the silver bronzing powder areas. I mention this so that you can avoid it. When I applied the background colour, I thinned the paint slightly with turpentine. I assumed that the turpentine would dry fairly slowly and not cause any reactions, since it's a fairly mild solvent, but I was wrong.

Luckily these areas were fairly small, and I was able to flatten them out slightly once the paint had dried. If the reaction had been worse, I would have had to strip off the glass completely, and start over from scratch.

The background paint needed 2 coats (since it was thinned), and I did not thin the second coat. I'm very happy with the finished glass. You can also see in the next photo how nice and wavy the glass is.

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