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Bowling Balls versus handmade
concrete hypertufa spheres:
Bowling balls are cheap and
can be found at garage sales. Many people have asked me do
they crack. This has been my experience. Different
bowling balls are made from different formulas. Think about
the flat black ones versus the ones that are striped with shiny
rivers of glitter. I've had plain bowling balls left in the
sun, not with mosaic on them, for a couple of years and have
seen no cracking.
But, just early this year (2008) I
put mosaic on a ball. It was partially in the sun.
Well, I noticed a crack in the mosaic. This is quite disappointing
when you spend a week working on a project. I will attempt to
repair but it will never look as good as the original
product. I believe the crack was due to the expansion of the
bowling ball from heat build up and with the mosaic around it, it
had no where to go and the fracture occurred. My bowling ball
by the front door is mostly in the shade and has not cracked.
The hyper tufa spheres are
a different animal altogether. They are made from different
mixtures of concrete, sand, and fillers. I usually add an
admixture/liquid as an extra measure to help prevent expansion and
contraction during freeze/thaw cycles. It also helps
strengthen the product. I've never had a hypertufa sphere
crack. I've dropped it and it's broken, once. On a
photo shoot one of my orbs fell off my dolly. Oh well....
In
the future, I plan on having the cement mixture orbs for sale
that are plain, for you to mosaic yourself.
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