Glass Mosaic Gazing Ball - Part 3

My apologies for the look of the blog today.  For some reason the blog platform is giving me a problem and I am not able to control the look of the blog.  Thins are getting way out of line and I am not able to fix it.   

In the previous two posts I had blogged about taping the ball with waterproof foil tape and how to determine the amount of glass you will need to cover the sphere.  So now it is on to mounting the glass to the sphere.  In this case, I am using a bowling ball for the base of the sphere.  Although this would seem to be a straightforward process, there are a few things that you might like to know about before you begin.  A little bit of a heads up can save a few mistakes here and there.   

                     

To make this glass mosaic gazing ball, I am using vitreous glass tesserae .  Tesserae are sometimes referred to as glass tiles.  This glass looks as if it is opaque, but it is actually translucent.  When you hold it up to a light source, you can see the diffused glow of light coming through it.  I expect that sunlight going through the glass and bouncing off the foil tape beneath will give the sphere a nice glow.  This glass was comes mounted onto sheets of brown paper with water soluble glue.  The advantage of ordering the glass in sheets is that you can figure out how many square inches you can cover with a sheet of the glass.  If you are buying glass tesserae by the pound, it is more difficult to figure out how much glass you will need for the project.  Glass is heavier than you think and will vary by the type of glass you choose.  For this gazing ball, I chose to use a single color of glass so that it will closely resemble the shiny gazing balls you see in garden centers, but the choices of materials,

colors, and patterns are virtually endless.

Vitreous glass tesserae.

 There are a couple of methods for removing the glass from the paper.  If you have a large enough work space and equipment, place the sheet in a pan of water and let the glass soak for a few minutes.  They will come off easily.  A useful method for a smaller work area is to protect your work space with plastic, lay down some paper towels, and place the glass side down on the paper towels.  Use a spray bottle to thoroughly soak the brown paper.  Allow the water to soak in for a few minutes, then peel off the brown paper.  It has been my experience with this method that little bits of the paper stay stuck to the glass.  I always give my tesserae a good rinse to remove the little bits of paper and wash off any remaining tacky glue.  Once the tesserae are clean, they are ready to mount on the sphere.

Paper backing on the glass.

Glass and adhesive can slide on the curve.

As I mentioned in a previous blog, the tesserae need to be no larger than 3/4 inch square.  Anything larger will not lay flat against the curve of the ball.  I use GE 100% Clear Silicone to adhere the glass to the ball.  I purchased the 2.8 oz. (82.8 ml.)  tube.  Wear gloves.  The uncured silicone can irritate skin.  The silicone is stiff in the tube.  It takes a fair amount of hand strength to squeeze out the adhesive.  With the small tube, you have enough control to squeeze the silicone onto the tile.  With a little practice you develop an idea of just how much silicone to put on the glass so that when pressed onto the ball it squishes out just enough to cover the tile without going over into the spaces between the tiles.  If you find that it hurts your hand too much, the other option is to purchase a tube and use a caulk gun to squeeze some of the silicone onto a pallet.  Then use a small knife to "butter" a bit of the silicone onto the back of each tile.  Eventually, the tip of the tube will clog.  I found that clearing the tip of the tube by forcing a small wooden skewer through it will clear the tube for further use.  The large tube will be much more silicone than you will need for more than one gazing ball.

So now on to a few useful tips.  First off, take care that you do not get any silicone on the front of the glass.  Once it dries, it can be scraped off, but it is a lot of work.  On my first ball, I was less cautious about keeping the silicone away from the front and I had a lot of scraping to do.  I used a dental tool to remove the silicone from the glass.  It was a real mess to clean up.  And, the floor of my studio became slick from the little bits of silicone.  It took a number of clean ups of the floor to keep it from being slick.  Seriously, it was so slick it was like walking on ice.  It is better to be cautious in the first place rather than to have to do so much clean up.  Make sure that your fingers are all the way to the tip of your gloves.  Part of my problem is that the gloves were larger than my hands and the overhang of the fingertips was what caused me to get so much silicone on them.

Understand that working on a three dimensional object requires some planning.  You will only be able to work on a small area at a time.  Once you get too far on the curve of the sphere, your glass will start to slide.  The silicone adhesive is viscous, but takes a while to set up.  Check the areas constantly to make sure that your tiles have not slid down against each other.  Remember that you need to have a minimum of one eighth of an inch between tiles in order for the grout to get between the tiles.  If not enough grout gets in, the tile may be loose and fall out when you are cleaning the tesserae after grouting.  At best expect to have five to ten minutes work time.  Then you will have to wait until the adhesive sets up enough that the glass will not slide when you turn the ball to work on a new area.  This will mean pulling gloves on and off constantly.  I have read in safety papers on art materials that it is recommended that gloves not be reused.  However, many people do reuse gloves, so I will make a further comment for those who do reuse gloves, at least on the same project.   Do not put the gloves up to your mouth and blow in them to push the fingers out.  That would be putting chemicals up near where you eat and breath.  Enough said on that matter. 

Some people may decide to just place their tiles at random, but having a plan for your grout lines can enhance the look of your mosaic.  In my last blog post I showed a couple of patterns of laying the tesserae an how that affected the look of the grout lines.  For this ball I have chosen to have horizontal grout lines.  Keeping a straight line while adhering tiles around a sphere is not easy.  You could end up coming around the sphere and find that your line has become too high or too low to meet up with your initial tesserae.  If that is the case, then you have a choice of turning your line into a spiral around the sphere; removing the tiles and gluing them on again; or adjusting the remaining tiles to try to correct the line which will leave the line with a dip or rise in it.  In this case, an ounce of prevention is worth a pound of cure.  Before laying the tesserae, use a large rubber band and a ruler to create a line around the equator of the ball.  Use the ruler to make sure that the rubber band is the same distance from your work surface all the way around.  Once satisfied that all is in order, mark the line with a marker and remove the rubber band.  Then you have a starting line that is even all the way around the ball.  Lay that line first.  Then work up and down from that line, turning the ball to bring your next area facing up.

You may also run into the problem that you don't have enough space to make the last tile fit.  Make slight adjustments to the last few tesserae laid.  The silicone has a fair amount of set up time, so you should be able to made the adjustment with no problem.  In the worst case scenario, you might have to pry up a few tiles and shift their positions slightly.   If the correction is made over two or three inches, the difference will be hardly noticeable.  Just make sure that you leave a minimum of one eighth of an inch between the tesserae so that there will be enough room for the grout.

As you work up towards the top of the sphere, make sure you check previous work to make sure that none of your glass has moved.  If it has, gently pry it up and glue that section again.  You will also find that you have to tip your tiles slightly to accommodate the curve of the ball.  At the very top, you are going to have to make some decisions on how you want the grout to look.  At some point, your grout lines will change as the you run into the problem of having squares on a curved surface.  The grout lines will be wider at the bottom and thinner at the top.  At the very top, there will be larger grout spaces between the squares.  You can choose to leave it like that, or you can choose to cut some of the tesserae to fit into those gaps.  If you cut tesserae, you will have a sharp edge on the glass.  Some of the sharpness can be blunted by scraping the glass against fine sand paper (or using a glass grinder if you have one).  In any case, make sure that the edge of the glass is well covered when you grout the ball.  Use care when grouting the ball that you do not cut yourself on the sharp edge.

I guess I will end today's blog here.  Next blog post will be on selecting grout and grouting the ball.