Glass Mosaic Gazing Ball - Part 4

Ready for grouting

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This week I completed adding the glass tesserae to the sphere.  All that is left is for it to be grouted.  I'll have to make another trip to the hardware store.  I guess some readers wonder why I did not buy the grout when I went to the hardware store for waterproof foil tape and silicone adhesive.  A legitimate question, and in this case I have a reasonable answer.  I live just about equally distant from two big name hardware stores.  One is more focused on the home improvement sector while the other markets to builders and contractors.  They don't always carry the same products; and if they do have the same products, the products come in different sizes from one store to the other.   One store did not carry the waterproof tape, so I ended up at the other store, which had the tape and silicone.  It had the type of grout I wanted but in huge contractor size units.  It was not going to be cost effective to purchase such a large bag because it was considerably more grout than I needed.  Once you open those bags, moisture and humidity can cause the material to harden over time.  So the material needs to be used in a relatively short period of time.  It was more cost effective to make a trip over to the other store to purchase grout in a smaller size.  Of course, you are paying more per unit of weight for the smaller size bag, but for this project it is still enough of a savings to make it worthwhile. 

I decided to set the tiles at about a quarter inch apart in order to accentuate the grout lines going
around the ball.  Using a wider grout area also used less of the glass, which helps keep the cost of the sphere down.  It will of course cost more in grout, but because this is a more expensive type of glass, using more grout is cost effective. 

Using a wider grout line also helps to anchor the tesserae and make the glass more secure on the sphere.  The grout needs to set up around each piece of glass and secure it in place.  If the glass is not entirely surrounded, or did not receive enough adhesive, a tesserae could become dislodged during the cleaning process that occurs after grouting.  If a piece comes loose, you have to chisel out the grout, reapply the silicone adhesive and tile, allow that to dry, and then re-grout the disturbed area.  It is a bit of work, and a real annoyance when you think you are just finishing up a project and find out that you have to make a repair.   By making sure that you leave at least an eighth of an inch between each tesserae you can save yourself some work.

Another reason for the wider grout line is that the grout lines can be used to be part of the pattern of the gazing ball.  A closer grout line would make the ball look more like solid glass.  By having wider grout lines, the line themselves form a visual pattern.  In this case it will be lines circling around the sphere horizontally.  The glass I am using has lines cut into the glass.  I have laid the tiles so that all the line are horizontal also.  This should give the appearance of directional movement to the gazing ball.  At this point, it is not easy to see, but once the grout is in place, it should be more noticeable.

Today it is pouring down rain.  Earlier this week we had an ice storm.  Tomorrow should be nice, and I hope to get to the hardware store.  I expect to have the ball grouted by Thursday.

Next blog post I will be writing about how the choice of grout color can affect the look of the ball and about grout additives.