A. Introduction:

A composite material (also called a composition material or shortened to composite, which is the common name) is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure, differentiating composites from mixtures and solid solutions.

Typical engineered composite materials include:

• Reinforced concrete and masonry
• Composite wood such as plywood
• Reinforced plastics, such as fibre-reinforced polymer or fiberglass
• Ceramic matrix composites (composite ceramic and metal matrices)
• and other Advanced composite materials


Composite(Source:https://upload.wikimedia.org/wikipedia/commons/1/13/Composite_3d.png)

Tools / materials / items used For this exercise, the following are needed::




• Epoxy resin
• Hardener
• Surgerical / rubber gloves
• A bowl
• Spatula
• Weighing machine (mid-sensitivity / range)
• Heavy weights
• Plastic wrap
• Flat wooden/mdf/metal boards (for flattening purpose)
• Jute cloth
• Newspapers / any other thin paper
• Finishing material sheet



RESIN




1) Resin used





2) Proportions





3) Weighing






The steps to follow




• Wear the gloves before starting the process.
• Cut 4 peices of jute and newspaper each (about 30cm x 30 cm). The 5 cm margin on each side is to compensate for the loose ends left on the edges and to give extra space for laser cutting at the end of the process.
• Wrap two large boards with plastic wrap (between which the composite is going to be compressed).
• Mix the Epoxy resin and the hardner in a ratio of 2:1 (2 units of resin and 1 unit of hardner). Use the weighing machine to measure the amount of the resin and hardener. Mix the mixture till it it starts getting harder (for about 5 minutes).
• Place a sheet of paper and apply the mixture with scapula. Place a layer of jute cloth over the paper and apply the more of the mix. Repeat the process again and again such that the composite has alternate layers of jute cloth and paper (soaked well in the epooxy mix).
• wipe out extra resin on the sides.
• Sandwich the composite between the wrapped board pieces and place it under the heavy weight. The weight should be large enough to uniformly compress the composite and should be heavy enough to compress it well.
• Wait for about 24 hours for the epoxy to dry well. Take out the composite once dried.
• Make the final finishing by cutting the edges by means such as laser cutting machine, sanding, etc.



Compressing the composite




Composite after laser cutting





Precautions:




The following points are to be considered before you start the exercise:

1. Wear gloves at all time during the exercise
2. Work carefully with chemicals.
3. Make sure that the weight is placed uniformally over the material while compressing.
4. Do not leave extra mix in the bowl. Clean it once the exercise is completed.
5. Do not rub your eyes or touch any body part with your hands while working. The chemicals might get on to your bare skin or eyes.

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