S U S T A I N A B L E     T E C H N O L O G Y     E D U C A T I O N     P R O J E C T
home  |  about Practical Action  |  contact us  |  site map  | 
The materials on this site are no longer being updated. For Practical Action's main school site go to www.practicalaction.org/schools

Identifying plastics




You could try making your own batch of natural soap. Before you get started, it is vital that you follow these safety instructions.

What equipment will you need?

What ingredients will you need?
  1. Grease your mould using a paintbrush dipped in melted fat. Cut two pieces of greaseproof paper and line the base and sides of the mould.
  2. Melt the solid coconut oil in a large pan.
  3. Add the liquid oils to the pan and remove it from the heat.
  4. Pour the water into a large plastic bucket and add the caustic soda to the water to make lye water. Begin stirring as soon as you start adding the caustic soda.
  5. Bring the oils and the lye water to a temperature of between 35 and 36.7 C. You can do this by putting the containers in a sink of warm or cool water, depending on whether they need warming up or cooling down.
  6. Add the lye water to the oils and stir continuously. The mixture should gradually thicken and become more opaque. Once you can see tracing - the impression of a line of soap on the surface when you drizzle the mixture from a spatula - saponification has occurred. This usually takes about 40 minutes. If it still hasn't traced after an hour, leave it and stir occasionally until it thickens.
  7. Add any colours or scents that you want and stir well.
  8. Pour the mixture into the mould.
  9. Cover with cardboard and thick towels. Leave to set.
  10. After 24 hours, turn the soap out of the mould onto greaseproof paper. It is still caustic at this stage, so make sure you wear gloves and goggles. Remove the lining paper.
  11. Cut the soap into bars before it gets too hard. Leave it to cure for at least one month in a warm, dry place on greaseproof paper. Before using the soap, test its pH with pH paper to ensure it is mild enough (anything between 5.5 and 10 is safe).

next page »



print this page back to top
Practical Action - Technology challenging povertyEuropean Commission - Department for International Development

S U S T A I N A B L E     T E C H N O L O G Y     E D U C A T I O N     P R O J E C T