Glass Mosaic Gazing Ball Part 2- Glass Selection

One hole filled with foil the other topped with Silicone.

When I blogged on Thursday, I left off with covering the bowling ball with waterproof foil tape.  The entire ball was covered except for the finger holes.  That is where I will start today, then I will move on to glass selection.

Before I begin, a couple of safety reminders.  Always use glue in a well ventilated place.  Wear gloves to protect your hands.  The uncured product can irritate skin.  

Glass tiles on paper backing.

The finger holes in a bowling ball are deeper than one would think.    I use GE Clear Silicone that is used for windows, doors, etc.  The product comes in different colors, and you can use a different color if you wish, but clear is the better choice because it will allow more light to filter through to the reflective tape and bounce back through the glass. I fill one finger hole at a time.  I begin by squirting some of the Silicone adhesive that I will be using to adhere the glass to the gazing ball into the hole and use a craft stick to smear some of the adhesive around the sides.  Then I stuff the hole with aluminum foil until it reaches the top of the finger hole.  Then I complete the fill by using more of the Silicone adhesive until the hole is level with the bowling ball.  I complete the other two holes in the same fashion.  Then I let it cure for a while.  Once the Silicone is dry, I cover over the hole with more of the waterproof reflective tape. 

Now, on to selecting glass for your gazing ball.  There are lots of choices and the choice of glass will have a big effect on how your completed ball will look.  With every ball I try to experiment with a different type of glass to see what happens.  Glass gems, those semi-spherical pieces of glass glow and disperse a lot of light.  They also have the advantage of being smooth and you are not likely to cut

Glass patterns.

yourself on them unless one breaks.  The disadvantage to glass gems is that they give your ball a lumpy appearance.  Stained glass does not have as much of a glow to it as the glass gems, but it give you more lee way to create a pattern.  You can buy it already cut into tiles, but your choices of color may be  somewhat limited.  You can buy stained glass and cut the tiles yourself, but they will have sharp edges where the commercial tiles are generally beveled to avoid sharp edges.  The edges of your cut tiles can be blunted somewhat by placing them in a sealed plastic container and giving them a vigorous shaking.  After that, the tiles need to be rinsed and dried because they will be coated with glass dust.  (Wear a dust mask when dealing with the glass dust.)  Iridescent glass is more expensive than regular stained glass, but it has a beautiful glow.  You don't necessarily have to use glass, shells and small objects can also be used in a gazing ball.  View my post for April 16th 2014 to see examples of gazing balls with glass gems, iridescent glass, and stained glass.

For this project I used some purchased glass tiles that I had in my glass stash.  Yes, I have lots of glass.  My husband and I found that beautiful glass is just as addictive as fabric is for quilters or gem stones are for rock collectors.  So now I am trying to use some of it up.  These glass tiles are 3/4 of an inch square.  If you are purchasing or cutting glass tiles for a gazing ball, make sure that your tiles are no larger than 3/4 inch.  A larger tile will not sit flat on the cured surface of a sphere the size of a bowling ball.  Smaller spheres may require a smaller size tile.  You can purchase them as small as 1/4 inch square.  This pretty much means that most of the small glass tiles you see in your local home improvement store are going to be too large for this type of project.  You might be able to find them in your local glass shop, but more likely you will have to turn to the internet to purchase them.  The glass tiles are adhered to the brown paper by water soluble glue.  The paper should be removed before proceeding further.  More on that in the next blog post on Thursday.

The next step is to determine how much glass you need to purchase.  You want to make sure you have enough.  You don't necessarily want to purchase more than you need.  Glass and shipping charges are expensive.  So you have to figure out how much area you need to cover.  There is a formula for determining the surface area of a sphere:  A=4πr²

I will type out the explanation.  Area = 4 x Pi (3.14159) x radius squared.  For example, if your ball has a ten inch diameter, the radius would be five inches. The radius squared would be 25.  The math would be 4 x 3.14159 x 25 = 314.159 square inches.  Wait what?  That is what I said the first time I did the math.  If your ball has a different diameter the answer will be different and it will not look like you took the figure for Pi and moved a couple of decimals.  (And you thought you would never have to use Algebra once you got out of school.) But wait, you say.  How do you figure out the diameter of the sphere.  I could give you another formula, but lets do this the easy way.  Put you had at the equator of your sphere.  But a ruler up against your hand.  Support the ruler with your other hand and place your hand on the equator on the opposite side.  The number on your ruler will give you the diameter of your sphere.  Close enough anyway. 


So now you know how many square inches of material you will need.  If you are cutting tiles yourself, you will need to figure that you need a minimum of an eighth of an inch between each tile for the grout.  If you are purchasing glass tiles, it could be figured in for you.  The photo of the glass tiles shows that they come fastened to brown paper with an eighth of an inch between each tile.  The square of tiles is 12.5 inches on each side.  12.5 x 12.5 = 156.25 square inches.  156.25 x 2 = 312.50.  That is very close to the 314.159 square inches that you need.  You can choose to space your tiles wider than an eighth of an inch and you could probably get by.  Or you can order three sheets of tiles and have some left over to be used in another project.  Your choice.  Just remember, if you found something you liked once, it may not be available the next time you order.   If you can't make it work and you can't find more, then you have to figure out what you will do to complete the gazing ball.  It is not a disaster, it is just one of those happy accidents that make your ball unique.  Take this into consideration before you make a purchase.  It can save you from being disappointed.  Note that one tile in the photo is broken.  That tiles sometimes break should be taken into consideration when ordering.  This tile broke after it arrived here.  If it had arrived broken it could be went back, but then you are playing the waiting game and maybe they have more or maybe they don't.

Now that the choice of glass has been made and purchased there is another decision to make.  The pattern.  How you choose to lay out the tiles on the sphere will have an effect of the look of the sphere.  Note the photo captioned Glass patterns.  You can lay them out so that they have a grid effect or you can lay them out so that the pattern of the grout has a linear effect either horizontally or vertically.  In the upper layout the lines will have a grid-like effect.  In the lower layout the grout lines will have a more noticeable horizontal line.  Or the orientation of the tiles could be changed to have a more noticeable vertical line.   Another possibility is that the tiles could be laid randomly and/or with other objects so that no specific pattern was seen.  The placement of tiles will have a marked effect once the sphere is grouted.

I will have more on grout choices on my blog post on Thursday.