IN: Competition advice

Top Tips From Finalists

We caught up with our past winners for advice and top tips when working with cement/concrete:

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  1. What is the main challenge you faced when working with cement/concrete and how did you solve this?
  • Applying the concrete mix: Once you have made your concrete mix, applying it to your preferred shape may prove difficult. Trial and error are the key to overcoming this obstacle in the production.
  • Achieving the ideal weight: Because concrete is heavy, increasing scale becomes difficult from a logistical point of view. The thinner the concrete, the weaker and more fragile it is, and so to balance these two properties you should use glass-fibre-reinforced concrete. The resulting mix is much stronger and so a piece can be enlarged without being too heavy.
  • Bubbles: Especially in pieces that are detailed, like jewellery, bubbles can be problematic. To prevent bubbling, hand-sculpt rather than use traditional moulds made from silicone or plaster of Paris. Sculpt the concrete into the pieces and let them dry slightly, then re-sculpt them into the desired form.  

 

  1. What did you take into account when using or designing a concrete mould?
  • You must first have a good sense of the product you want to create before crafting the concrete mould.
  • Working backwards from the “finished product” can help smoothen the mould-design process.
  • Make sure that the mould can be removed as easily as possible and does not damage the cast concrete. When using a silicone or Plaster of Paris mould, make sure there is enough silicone or Plaster of Paris to support the weight of the mix being inserted into the mould.
  • Moulds can form bubbles in the mix and therefore might not be suited to more detailed design concepts.  

 

  1. What did you do to ensure the mix sets properly?
  • Use the correct ratio: Not only must you use the correct ingredients, but the correct ingredients in the correct proportions.
  • Experiment with consistency: Setting is the most crucial process and production must include time for errors. If your work does not set correctly, you can then scrap it and head back to the drawing board.
  • Minimise water content:Less water will increase the bond strength and prevent bubbles forming in the cement mix. Some additives help to loosen the mix and therefore lower the water content that is necessary. Covering the mix with a plastic sheet will trap moisture and result in a much stronger cement mix.

 

  1. How did you calculate the ratio of ingredients in the concrete mix?
  • Seek guidance from an expert(s), be it an architect, engineer or student in a related discipline.
  • Search for online resources that provide clarity on ingredients.
  • Because each entry is a unique product, trial and error will help to determine the correct ratio of ingredients.

NOTE: First experiment on a smaller scale than that of your actual product.

 

  1. Which admixtures (if any) did you use and why?
  • Especially with jewellery pieces, micro-balloons can help to decrease the weight of the cement mix. After all, you want pieces that are comfortable when worn by the consumer. 
  • Forton VF-774 lowers the amount of water needed in the mix and eliminates the seven-day wet cure that is required to achieve maximum strength. It also helps to prevent cracking due to concrete shrinkage. 
  • A plasticiser helps to decrease the viscosity of a cement mix without increasing the water content. The resulting mix is more workable.

 

  1. What tip(s) would you give someone who has never worked with cement/concrete and who has entered or plans on entering the PPC Imaginarium Awards?
  • Finding technical information about concrete is fairly straightforward. Be resourceful in your search for guidance, be it online or from a person with concrete expertise. 
  • Give yourself time to make mistakes. During production, failure will mean you have to repeat or re-do certain processes.
  • Have fun with the material. The competition lets you push your creativity and problem-solving skills, and don’t forget – if you don’t make it then you can always re-enter in the next year!
  • Once you get going, production is much easier than you may anticipate.

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