Some Final Experiment Results from the Sphere Mold

Waterproof plumbing tape sticks where other tape peeled off.

I had a few final thoughts and a final experiment on my sphere mold.  My goal was to create a low cost sphere that could be used as a base for making mosaic gazing balls.  The sphere had to be able to stand up to the weight of glass and grout, and be able to withstand outdoor weather conditions.  I had hoped to create a mold that could be used to cast numerous balls.  As I blogged last time, trying to create a sphere with expanding foam was futile.  However, I don't consider it a waste of time.  As Thomas Edison is quoted as saying about the light bulb, "I have not failed.  I have found 10,000 ways that won't work."  I will continue to experiment until I find what does work.  I merely have to rethink the situation. 

In the last blog post showing the still wet, sticky foam that remained inside the sphere mold.  I had left it to dry wondering whether the foam could be removed from the mold.  I had coated the mold liberally with mold release.  Once dry, the foam did not release from the mold.  I guess that was wishful thinking on my part.  After all, the product is designed to stick in cracks and not come out.  However, that started me thinking in a new direction.  Suppose that each mold was a one off mold rather than a reusable mold.  What if I sprayed foam to fill each half of the sphere mold.  When the foam was dry,  maybe use a saw to saw the foam level with the top of the mold.  Then glue the hemispheres together with construction adhesive.  That might possibly work.  I guess I will have to experiment. 

My next question is whether the mold itself would be waterproof enough.  It is raining this morning.  I am going to toss the mold pieces outside to see how they hold up outside over time.  I have seen papier mache' pieces designed to be kept outside.  The glue made them waterproof.  So I have some hope of the mold lasting in outdoor conditions.  Whether my method works or not remains to be seen.

Another experiment was to find out if a different tape made a difference. As I blogged last time, the mold was highly resistant to both masking tape and duct tape.  Both tapes tended to curl off from the mold.  Long time readers know that I generally wrap my sphere base in a reflective, waterproof plumbing tape before gluing on the glass and grouting the ball.  It may not matter if the mold is completely waterproof if it is covered in two additional layers of materials.  The waterproof tape has a very thick, sticky adhesive.  It is much stickier than either of the other tapes. I tried the waterproof tape.  It worked.   The waterproof tape is not peeling up off the ball.  So maybe, if I made taped foam filled hemispheres together I would not even have to purchase some construction adhesive.  Hmmmm......It sounds like another experiment is in the cards.

(Note:  the reflective, waterproof tape is not the reflective tape that is used to tape dryer ducts and air conditioning vents.  Its shiny exterior looks the same, but the adhesive is different.  Make sure the tape is marked waterproof.)

Now that I know the waterproof tape will stick to the ball, I also had another thought.  Suppose I had made the mold as I have blogged about.  Then I cut a hole large enough to remove the ball.  Then I filled the ball with sand or gravel.  Then glued the piece of the mold I had removed to extract the ball back in place.  That ball would be as solid as could be.  The waterproof tape, silicone used to glue on the glass, the stained glass, the grout, and the sealer for the grout would pretty much make that ball impermeable. It sounds like another experiment is in the cards.

I am sure the everyone wonders why I persist with trying to make spheres out of ridiculous materials.  The main reason is that I like to make gazing balls, but they are expensive to make.  I like to keep my hobby costs down.  For the mold I was making for these blog posts, the costs came to roughly $1.74 cents worth of glue. $3.38 for the spray foam, and some scrap flannel.  Playground sand - $3.99 for a fifty pound bag.  Or aquarium gravel is $2.09 for a five pound bag.  Child's ball to use as a mold - $1.99.  So about $11.10 for this project.  (Cost figured using the figure for playground sand.)  I have not checked to figure out volume, so it could take two bags of aquarium gravel.  I count the flannel at no cost the costs for the material had already been absorbed in other projects.  It would have been thrown out if I had not used it for this project.  I expect that many people  have some old flannel shirts or an old flannel blanket that have seen better days and could be used in a project.  Roughly eleven dollars is a lot less expensive than some of my options.  Sometimes I can find a bowling ball for free, but many sell for as much as $35.00. 

The costs for Hypertufa in round numbers:  concrete mixing tub, $12.00, portland cement $11.00, pete moss $10.50, vermiculite $12.00.  That comes to $45.50.  This is presuming that you already have a hoe and a trowel.  A half-sphere mold can run $20.00 to $35.00.  If you have a lot of patience, you can get by with a single mold and cast the half spheres sequentially to get two hemispheres to glue together to make a ball.  Otherwise the costs for the mold doubles.  The other problem with casting Hypertufa is that the materials are generally sold in large batches.  For example the portland cement comes in ninty-four pound bags.  Sometimes you can find them in fifty pound bags if you are lucky.  That is a lot of cement compared to what is needed to make a ball.  And once you open the bag, the clock starts ticking on the shelf-life of the product.  A Styrofoam ball at the craft store can run about $17.00.  Larger ones can cost much more.  So perhaps you can understand my quest for a less expensive option. 

Sooner or later I will get around to experimenting on spheres again.  I am planning to put my current project outside to check to see just how waterproof the mold really is.  Other than that, I will begin working on the toy-sized lamb project.  It may take a few days to get started, but I should have some photos soon.  I also have a couple of other projects to blog about.  Check back on Thursday for the latest.

Sphere Mold - Part 3

Registration marks on the mold.

Last time I posted I blogged about experimenting with making a mold of a sphere from flannel and glue.  My first experiment was whether I could make a rigid mold using those materials.  And yes, the mold held its shape once the mold was cut open and the ball removed.  The mold release allowed the ball to pull away from the mold, leaving me with a hollow sphere.  So far, so good.  Step one succeeded. 

Mold wrapped in layers of tape.

Foam flowed out of the ball  mold.

My next question was whether once the mold was separated into half spheres whether the mold could be put back together again.  With that in mind, I made and numbered registration marks at the four points of the mold's equator before cutting the ball open.  I had this question in mind because a previous experiment with a papier mache' mold had shown me that the lip of the mold was too thin.  It was hard to keep the hemispheres in place because the lip was so narrow.  The new mold cast with three layers of flannel and glue (see the two previous blog posts for more information on the construction method).  When I cut open the mold, I could see that the thickness of the mold was three-sixteenths of an inch thick.  It was enough lip to place one hemisphere on top of the other and have it stay there...more or less.  In future molds, I think I will put down at least five, maybe six layers of flannel.  I think that it would be easier to put the mold together if it had a slightly thicker lip.

Before I put the mold together, I had to think about using a mold release.  My hope was that I could reuse the mold to make a number of balls.  In any case, I wanted the ball to come out easily even if I never made another ball.  I coated both halves of the mold with a generous layer of petroleum jelly.  Was petroleum jelly going to work?  It did release the flannel mold from the original ball.  How a different casting material would react with that mold release I did not know. Again, an experiment to see what I could see.

Foam removed from the mold, mostly in one piece.

Foam leaked slightly from under the tape.

My plan from here was to put the mold back together and fill it with an expanding spray foam insulation.   Before putting the mold together, I cut a small hole in the top of one hemisphere so I would have a place to insert the spray foam nozzle.  Then I started putting the mold back together.  I guess this is one case that poor planning lead to something akin to slapstick comedy.  When I was making this mold, I was only playing around with some scrap materials in the studio.  I was working without a full plan, although I had an idea for putting the mold back together.  I know that professional quality molds have bolts that bolt the pieces of the mold together.  I was not planning to go that far ahead with this mold.  I had really only trying to see if a mold could be made.  My thought was that we had a lot of clamps in the downstairs workshop that I would use to clamp the hemispheres together.   I knew that the clamps opened a couple of feet wide.  What I did not think about was that the depth of the clamp was only about three inches.  My ball was roughly eight and a half inches.  Once I actually pulled out a clamp and examined it I realized that there was no way that the clamp was going to clamp onto the ball.  Then I had to come up with a Plan B.

Lower hemisphere.

Upper hemisphere.

Plan B was tape.  Lots of tape as it turned out.  As it turned out, the glue saturated flannel was practically impervious to both masking tape and duct tape.  I was trying to tape around the equator.  It was a rather trying experience.  I would line up my registration marks and get the ball set just right.  I'd get tape about three quarters of the way around and the first pieces of tape I had put on would start peeling off.  I would go back and try and press the tape down.  Too much pressure would cause the top hemisphere to fall off.   I would put the hemisphere back on and the tape would fall off.  It was probably hilarious if you were watching it, but not so amusing if you are trying to put something together.  Anyway, I finally managed to get the ball together by wrapping my body around it like a contortionist to hold the ball in place and then wrapping a long piece of  tape completely around  the ball so that the tape could stick to itself. 

I started with masking tape but I could see that it was barely sticking to the ball.  I repeated the process with duct tape.  The duct tape did not stick to the mold well either.  After numerous wraps of tape I finally felt I had the mold situated so that it would stay together when the expanding foam was added.  It looked like a big mess.
 
I had some strong concerns that the ball might not stand up to the pressure of the expanding foam. I put on my oldest paint clothes and went outside.  I also wore rubber gloves and eye protection.  Who knows what can happen when something is put under pressure.  I was just hoping that if the worst case scenario happened, the foam would not get stuck in my hair.

The can of spray foam did not enlighten me as to how much area the can could be expected to cover. All it said was that it could fill a crack up to one inch wide.  However it did not state whether it would fill a one inch wide crack for a certain number of feet.  There was no way with the information available to calculate how much volume of foam would be created.  Without that information I just had to guess whether it was going to be enough to fill the sphere or whether the sphere would be forced apart by pressure from too much foam.  I decided that I would start filling the sphere and quit adding foam once I saw that it was getting close to the hole I had cut for the spray nozzle.  My hope was that as the foam expanded it would fill the rest of the cavity and any excess foam would flow out of the hole for the nozzle. 

I added the foam and it did fill the cavity and then start to overflow out the hole.  There were a couple of places on the equator where the tape did not seal well and a little bit of foam about the size of a grape emerged.  The rest of the foam flowed out the intended hole.  I was wiping the excess foam away from the hole for about twenty minutes.  I did not want the foam to harden before it was finished expanding.  When the foam settled down to blurping more slowly and looked like mud blurping at a hot spring I went inside and left the ball to its own devices overnight hoping that it would dry up and seal off the hole. 

The next morning I went outside to see what had happened overnight.  The foam had continued to flow from the ball and formed a mound flowing down the side of the ball.  I took the ball inside to work on it at the downstairs workshop table so could use the shop vac if the foam made a mess when I cut it off the ball.  As it turned out, I did not need to use the shop vac.  The whole block of foam pulled off in one piece.  Apparently it was not very amenable to sticking to the mold either.

I used a utility knife to cut through the foam around the seal of the mold.  The mold was starting to move easily.  I was getting excited.  Then I opened it up and was in for a big disappointment.    Apparently the flow of the foam acted as a siphon.  There was barely any foam left in the mold.  Fortunately just before I opened the mold, I decided I should put down plastic for "just in case".  What foam that was left in the mold was still sticky wet.  Although it was supposed to be set up in twelve hours, it was still quite damp at nearly twenty-four hours.  I guess with hindsight I am lucky that the foam had flowed out of the mold.  That would have been a real mess to clean up if I had opened the mold and it all just fell out onto the worktable.  Note to self:  always unmold your experiments outside.  Anyway, the lower hemisphere of the mold held some foam.  The upper sphere was coated with a thin layer of foam.  I left them on the workbench to finish drying.  Just to see if the mold release was going to work. 

So that is the end of the experiments with this mold.  You win some, you lose some.  Conclusions:  the flannel and glue worked to make a rigid mild; future molds will need to have brackets of some sort for bolts and nuts to hold the mold together; spray foam may not work as a casting medium because it needs air to help the foam set. 

So there you have it.  An experiment gone awry.  But it did give me some insight into mold making and casting, so that is worth something.  Check back on Sunday for a blog post on a different subject.

My Sphere Mold

Ball mold cut into hemispheres.

Last blog post I wrote about trying to figure out a way to make a better sphere.  I make mosaic gazing balls.  The balls need a sturdy base to support the weight of the glass and grout.  I have been experimenting to find a way to make a base for the bowling balls that fit the following criteria.  It needs to be relatively inexpensive, easy to make, and sturdy enough to hold up in outdoor conditions.  To that end, I keep experimenting to see what is out there that will facilitate my crafting while staying on a budget.  I am still looking for an easier way to make spheres. 

Interior of the mold.

Before the mold was cut open.

For new readers, a quick recap of what I have done over the last few years in my quest to create mosaic gazing balls.  Detailed directions for crafting the objects are available in earlier blog posts.  I have used bowling balls as a base, cast spheres in Hypertufa, and even figured out how to create a papier mache' sphere that was covered in Portland Cement as a base.  The bowling balls were easy to use as they were already manufactured, but they are not easy to come by.  Mixing Hypertufa was a lot of work.  I was casting in a half-sphere mold because full sphere ball molds are expensive.  Mixing the Hypertufa and joining the hemispheres was messy work.  Plus the Portland Cement was only available in fifty pound bags at the hardware store.  It was a lot more than I needed.  Creating with Hypertufa was only affordable because we already had the concrete mixing trough from doing some home repairs.  The papier mache' base was had to be covered with layers of wire mesh and covered in Portland Cement.    Getting the sphere to retain its shape while covered with wire mesh was difficult, but the project has been able to stay outside summer and winter for the last two years.  All of the projects worked, but all had a degree of difficulty or expense. 

Yes, there are mold making materials available, but silicone mold materials for something the size of a ball would be expensive.  Plus a silicon mold would need to be reinforced so that it would retain its shape when filled.  Casting plaster around a ball would require cutting the mold open with some sort of power tool, creating a lot of plaster dust.  Still, that option is on the table for experimentation at some point in the future.  What I really want is something I can work with in the studio without creating a lot of mess.  Or at least made with only a minimal mess even if I have to work outside.  So this time I set out to try to create a spherical mold that I could use multiple times with inexpensive materials.

I decided to attempt to make a mold using what materials I had around the house.  I did not know for certain that it would work, but I strongly suspected that it would.  In doing some research on papier mache' I learned that people used to make small boats out of paper and glue.  It is hard to imagine what it was like to have the courage to attempt that.  However, small paper and glue boats were a way of life only a few generations ago.  If you could make paper and glue into a rigid, impermeable object, why not cloth?   If it failed, the main thing I was loosing was the time involved.

I used some scrap flannel and glue.  I purchase glue in gallon bottles at the hardware store because that is the least expensive way to buy it provided that you plan on making lots of projects that involve glue.  My mold project only took about two cups of glue total.  The flannel was left over from another project.  In fact, the flannel used in the last project was left over from a previous project.  So getting some of this old material out of my fabric stash was a win in any case.  My real question was how many layers of fabric was it going to take to make the mold rigid enough that it would not collapse when the ball was removed.   When working with my papier mache' ball base I learned the hard way that it would take more layers than I thought to make the structure retain its shape.

Sometimes you just have to guess.  (Note: to see the detailed instructions for creating the mold for see the blog post for Thursday, March 17, 2016.)  I decided to try three layers.  It was an arbitrary decision made solely upon that was how much scrap flannel I had available without cutting more from a larger piece.  It seemed quite rigid, so I decided to give cut the sphere in half and see what happened.  It worked better than I would have thought.  In fact it was so rigid, I had trouble cutting it open with a utility knife.  If I make another one, I will use a cutting blade with the Dremel tool. 

The inside was smooth, although you can see where the pieces of flannel are lying next to each other.  I am not sure how much those lines will appear in a cast object.  For my current ideas of application, I don't think it is going to matter.  In some places it was still slick from the mold release, but that will not be a problem.  I will be adding more mold release when I use it in the future.  In theory, this mold should be waterproof.  I guess I will find out about that as things progress. 

The outside of the mold is not a thing of great beauty, but for this mold, I was not particularly worried about what the outside looked like.  If I make future molds, I may keep that it in mind to make a smoother exterior.  I have a few ideas about how to use my new-found mold.  I will be blogging about them soon.  I have to make a trip to the hardware store before I use the mold.  I think I will be able to show you my first cast ball by the Thursday blog post.  Either that, or I will be blogging about the failure of the experiment.

Check back Thursday for the latest on the ball mold experiment.  Once that has been completed, I will begin working on the small version of the sheep/lamb.

My Quest to Build a Better Sphere

Ball covered in glue soaked flannel.

As I mentioned a few blog posts ago, I am working on a few projects at one time.  I am also playing a bit to decompress after finishing an intensive project.  At times like this I come up with some weird ideas.  I just want to play around with bits and scraps and see what happens.  At the moment I am playing around with a ball and some leftover fabric.  Hmm...., fabric some glue, and a ball....what could I do with that?  Lots of things actually.  I may have to make this project more than once to test out these ideas.

Concrete over papier mache' ball from 2014. Photo taken this morning .

  A few years ago I had been challenged to find something other than a bowling ball to use as base for making mosaic gazing balls for the garden. While it is  not impossible to find old bowling balls, they do not exactly grow on trees either.  I made a mold of a ball from papier mache' and used it as the base for a garden ball that I painted.  However the ball was rather cumbersome to make and required  extra supports from wire mesh to hold the Portland Cement outer layer.  I begin to think that perhaps there was a better way to make the support.  I set the idea aside until I was ready to work with it again.  I think that time has arrived.

My first thought is that if I could stiffen the fabric with glue and mold it around the ball, it might me stiff enough to hold its shape after the ball was removed.  If it did hold its shape, could I be able to use it as a mold?  If I was going to make a mold, could I use it to make some type of gazing ball substrate or as a base for some other project.  I decided that I would find the answer to that question.  And so the experiment began.

I had some small pieces of flannel left over from the Belsnickel project.  I cut it up into strips.  I had a ball that I covered with cling wrap and coated with a mold release product.  I mixed some Elmer's multipurpose glue 50/50 with water.  For the first course, I started adding strips to the ball and soaking them with the glue mixture.  I allowed the ball to dry completely.  It took about a day and a half.  I added a second course of the flannel, but this time a full strength layer of glue was painted on to the ball, then the strip of flannel was added and soaked with the 50/50 mixture.  The same thing for a third course.  Now I am waiting for the ball to dry.  It is almost there.

I plan to remove the mold from the ball soon.  Removing the ball will destroy it.  If I had thought about it a little more, I would have made sure I left an opening so I could deflate the ball.  However, I did not do that and the ball is covered in a solid layer of fabric.  Will it hold its shape once the ball is removed or will it collapse into a misshapen object?  If it does collapse, is there some way to make it more rigid and salvage it for the sphere project?  I won't know until I take out the ball.  Check back next blog post to find out.

For anyone who might be wondering if my ball with the papier mache' substrate has held up, I posted a picture I took this morning.    The ball was completed in 2014.  It is a hollow ball made from papier mache' and covered with Portland Cement.  Then it was painted with acrylic paints and sealed with an exterior sealer.  The ball has set outside summer and winter since the spring of 2014.  So far it has held up well.  The blog posts of the build of the ball are still online if you scroll back to the 2014 section on the main page of the blog.  The blog posts of my Hypertufa cast balls are also available.

Check back on Sunday and I will have unmolded the ball.  We will see what happens. 



     

Glass Mosaic Gazing Ball - Part 6- Grout

I have completed grouting the gazing ball.  I used a sanded grout.  If you look at the top of the ball, you can see that the grout is a little darker than the grout beneath.  I had to make a repair in that area.  The grout did not stay in that area very well when I turned the ball over to grout the underside.  A little of it came out and had to be filled in again once the rest of the ball was dry.  It will soon dry to to same color as the rest of the grout.

This repair brings up an issue that can be used as a helpful hint.  When you purchase a bag of grout, the
inclination is to dump the whole bag in and add your liquid then mix it up as per the directions on the bag of grout.  I generally hold back a small amount of the grout for a couple of reasons.  The first reason is that if you have added too much liquid to begin with, you have no grout left to help thicken the mixture.  I have had that happen more than once.  Having a little grout mix in reserve can save the day.  If you had to make a trip to the hardware store for more grout, your grout may have set up and could be unusable by the time you return. 

The second reason is that you may need to make a repair and if you have no grout left, then you will need to go purchase more grout.  In the case of this sphere, the grout crumbled out of the bottom and needed to be patched.  Another common scenario with mosaics is that a tesserae will come loose from its adhesive and come off when you wipe down the ball after grouting it.  In that case, you will need to clear out the area, re-glue the piece, and grout around it again.  If your grout has already set up before you find it, it is nice to have a little reserve grout around to mix up for a small repair.

When I mentioned mixing the grout with liquid above, I used the word liquid rather than water.  When you are purchasing your grout, make sure to read the directions.  Some grout works by just adding water.  Other grout only works if you add a liquid acrylic ad-mix.  If you add water to that, you are going nowhere fast.  Generally, you can add some acrylic ad-mix to the grout that calls for water.  Why use an acrylic ad-mix if you can use only water?  Because is will help prevent water from penetrating the grout.  The ad-mix essentially encases the grout mix in a plastic waterproof substance.  It could help your ball last longer.  Using the acrylic ad-mix will add to the expense of the ball.  Generally you have to purchase it in a gallon or five gallon size.  Once in a while you can find a half-gallon of it in a home improvement store on online.  You are more likely to find the smaller size online.  The current trend is to only offer the larger sizes in the stores. 

 For this gazing ball I used a light gray grout.  You have a few other choices, at most hardware stores you can purchase grout colors in white, gray, black, almond, and a few variations in the shade of those colors.  A little experimenting on paper before hand can help you with your grout choice.  The choice of grout color and help blend the mosaic together or separate the tesserae so that the lines becomes the most important visual aspect. You can find powdered additives that you can add to the grout when you mix it in order to have different colors.  Most of the time you will have to order and purchase the powdered additives online.  The colored additives are not found at all hardware stores.

You can also use paint on your mosaic gazing ball.  I have read that you can add liquid craft paint at the time the grout is mixed to obtain a desired color.  I have not personally tried this.  My experience with adding paint to another substance (a clay made out of drier lint) was that I had to add a lot more paint than I thought to make it the color I wanted.  It turned out to be much more expensive to add paint to the material than it would have been to have just painted the object the color I desired once the material had dried.  And if you end up not having enough paint to make the grout your desired color, you either have to settle for an unacceptable color or start all over again because more than likely the grout you have mixed will be unusable when you return from purchasing more paint.

Another thing I have learned about grout color is that bright white grout shows a lot of dirt; much more so than a gray grout.   As the gazing ball will be outdoors spring through late fall, it tends to collect a fair amount of dirt and grime.  The dirt against bright white will be very noticeable against the white.

I intend to embellish the gazing ball by painting the grout lines.  I have already started painting, but have not completed it yet.  You will see the embellished gazing ball on my Thursday blog post.  I think you will be surprised at how much painting the grout will change the look of the ball. 

Glass Mosaic Gazing Ball - Part 4

Ready for grouting

.

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.

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.