Hypertufa
Casting in hypertufa is fun
and not at all difficult. Hypertufa is
a mixture of Portland cement, sand and peat moss. If you want you can replace the sand with perlite, it makes
the pots and trays a lot lighter as perlite weighs almost nothing. Tufan takes a little longer to harden than ordinary
concrete.
When casting bigger things
it is a good idea to reinforce the castings. In my first attempt, I used chicken wire but I found it
difficult to fill the hypertufan in the mold when the chicken wire was
there. Then I bought a woven
glass fiber cloth, which I unraveled. I
cut the fibres into 3-5 cm pieces. One
handful of this mixed in each batch hypertufa seems just right. This reinforce and holds the Tufa together without
problems.
A concrete mixer is very
useful and makes the casting so much easier. I bought the smallest one I
could find and It is just the right
size for my needs.
When casting larger pots and
trays, I use buckets of different sizes ordinary cardboard boxes and
plastic tubs as molds.
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Rhubarb Leaves
Rhubarb
leaves
become
very
nice
bird
bath
and
stepping
stones.
In
order
to
cast
a bird bath, you need a large rhubarb leaf and a small or a piece of a
leaf, sand and concrete. It is good to have a tarpaulin or similar to
be on when casting.
Pour up a small pile of sand, it is good if the sand is damp. Shape the
pile as a low hill with flat sides. I cut away the stem and carve so it
will be as flat as possible where the stem was. Lay the leaf up side
down on the sand. Take the small piece of leaf and place it under the
big leaf where the stem was, this is just because the leaf is heart
shaped. This will prevent that the bird bath will leak.
Mix the concrete and pat it over the leaf so that it becomes thinner
towards the edges and thicker in the middle. Try to stay inside the
leaf edge, it will look better that way. When finished, put a plastic
sheet over it and let rest for two days before you turn the bath.
Then you can gently start peeling away the leaf. You will probably not
get rid of all leaf residue at once. It's better to let it be fore some
days so the leaf will dry. Then you can brush and scrub off the residue.
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In anticipation of the leaf to dry so it becomes
easier to peel
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A really big leaf 30x36"
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"Rubber door mats"
A
really nice thing you can cast, is larger stones using rubber doormats
in a
mold. I got hold of two different rubber mats with different size. I
made one mold for each mat. I used a steel mesh to reinforced the stone
because it is so big.
When casting, I filled one layer with concrete in the mold, then I put
the steel mesh in and one more layer of concrete. I patted down the
rubber mat up side down.
Then, I left it to harden for two days before I took apart the mold and
the rubber mat was removed. To get a nicer finish I used a rotating
wire brush to get rid of the casting flash.
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16x24"
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18x30"
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Balls etc.
When you are up in casting
you start to look for objects that can be used as a mold. One day we went to a store where I saw a bunch of
soft rubber balls with knobs on. It
struck me suddenly that they could be used as a mold if you cut off the
valve and turn them inside out. We also
had a mini beach ball lying around at home. It cut it up too!
After filling a ball with
concrete I dug a round-bottomed pit in our old sandbox and put the ball
in. I left them in the sandbox to rest for a few days before I picked them up and cut a straight line down the
side of the ball and then wriggled it out. I could then reuse the balls by taping together the cut again.
Sand molds for children
gives great little figures. Bowls and
plastic tubs of various sizes will be fine concrete bowls. Some I have decorated with glass beads that I
pressed into the concrete.
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Stepping stones
I found an incredible
variety of molds on eBay and I had to try this. It's amazing how well it turned
out. The molds are made in plastic and can be reused many times. Now I
just have to find out how I can use all the things I have casted. I
have some plans ...
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8x8"
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12"
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8"
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14"
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12"
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10"
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13"
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12x12"
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11"
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2,5"
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3x5"
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12"
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12x12"
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10"
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12x12"
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13"
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15"
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13x13"
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12x12"
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9x11"
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9x7"
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10x5"
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