Smash and Grab Bowl_Cast Concrete + Glass.

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Introduction: Smash and Grab Bowl_Cast Concrete + Glass.

This is a bowl cast from concrete, utilising glass fragments from one of the infamous ‘smash and grabs’. I am not sure if this is an international term, of if it is mostly understood in my hometown Johannesburg and the rest of South Africa. I have featured this on my website, but I know that Instructables reaches a lot more people/ inventors/ magicians.

If you’ve grown up in Jozi (Johannesburg), you have more than likely seen the extra large glitter sprinkled messily beside your car. If not you, then someone you know. This sadly is not glitter. Rather, it is the cookie crumb trail left by the izinyoka (the snake) to whom you have just donated your car radio/speakers/ anything forgotten on your car seat. This happened one evening to a car parked outside my house. Lurking in the darkness with a dustpan and plastic packet, I collected all the glass fragments as I knew there may be a possible use for them in the future. These remained in a tub on my shelf for many months until I decided to use them as aggregate in a cast concrete bowl. It was a couple months after I made the badass concrete rocket, in which rubber fragments were used as aggregate.

The contrast of the matt, porous concrete and the sharp smooth greenish glass fragments create an interesting visual appeal. This however does not translate into an easily usable product for storing household items... The concrete grit will scratch your phone, or get transported on an apple and end up chipping your teeth.

Even though there are many sharp corners, they get enveloped by the concrete and create a relatively soft form.

What I would like to do next, is use a much higher percentage of glass, which may allow some light to pass through solid concrete. I have seen this online, but it is much easier said than done as concrete is a very difficult medium to 'tame'.

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    23 Comments

    Maybe crush up some wine bottles? Maybe some blue wine bottles would look good

    To All

    You may not be aware of this (the instructable author as well!)... So I won't give the initally 'unbelievable secret' away right here but I will give everyone a web site to the French Chemist that discovered this over thirty years ago and has great utility today...I dare say you could make a cup out of this and drop if from 250 feet and not break it... There is a lot on the web site and a book(s) you can buy to learn more about this and to make it yourself... I think that I am going to 'pour' my own house of it...in Granite.

    http://www.geopolymer.org/

    Here the U.S. Military is using it and there are a lot of great links in the below story too:

    http://www.wired.com/dangerroom/2009/10/super-concrete-in-the-us-military-iran-and-the-pyramids/

    Have fun!!!

    One can purchase hollow glass beads which can be used with the cement in lieu of sand. It can make the cement object semi translucent and can be used to form many types of items. Additionally the glass beads make the material much lighter and have a much higher thermal R value than standard cement. A 6 inch block of cement made with hollow glass beads can pass shadows through the brick in bright sunlight and is rigid and strong enough for a permanent building material. . The University of Alabama built a canoe using this cement mixture with fiberglass and carbon fiber and built a light weight strong and curiously flexible ( the lateral flex actually helped propel the canoe) racing canoe. As the beads are rounded one can create an extremely smooth surface of the cement items. The cost of the hollow glass beads is about 4 times the cost of standard sand but if one is interested in the special properties it is probably better that waiting for your window to be broken for material. Interesting project

    Nice bowl, but this is not an instructable is it?

    Sometimes you can just post a slide show to inspire others. :)

    Thanks everyone for all the feedback! I will sift through all my images and try find the photos of the actual moulding process...

    I am familiar with a smash and grab. It happened to me twise and I live in Lancaster Pennsylvania. I am preety sure it was not an amish person though.

    Also cast some concrete shoes for those caught smashing windows.
    Seriously, glass can show off its best with nice cracked edges. There is a special ice like gloss in the edges of a fracture. I like the way you did this more than if the glass was tumbled first. Small pieces of solid copper wire can add to the look as well.

    If you turn this into a proper instructable and tell us how you cast this I will tell you cool ideas how to coat the inside of this bowl with felt, leather or straw. -_-

    Well, this all very interesting but I sure would like an Instructable on how to make these beauties.