Wall-Hanging Flower Vase Part2: Making plaster mold out of original shape 

This is a summary: Place the unfired clay original onto the clear plastic mat. Set up the wooden slats around it as shown, taping them to the mat with strong tape to secure them in place. Seal the edges and corners by pressing in oil based modelling clay to make them watertight. Smooth the edges of the modelling clay with your finger, dipped in water. To calculate how much plaster is needed, measure the volume of the area to be filled - length x width x height (height needs to be enough to cover the clay original but you don't have to fill the wood all the way to the top). The volume in cubic centimetres is how much plaster powder you need: 1 cubic cm = 1 gram of plaster powder. The water to be added is 74% ratio of the plaster, eg for every 100g plaster powder = 74ml of water. But obviously check your own brand of plaster. Sift the plaster little by little into the cold water and mix gently with the wooden pin for about 3 minutes. Gently pour it into the area via the wooden pin as shown and leave it to harden for at least 20-30 minutes (it took about 1 hour in this video). Release the plaster mould from the wooden slats as shown. Use a tool to pick out the clay to start with until you can pull it out cleanly in one piece. Tidy up the edges of the plaster mould with some sandpaper and clean off any excess clay with a damp sponge. Next video he will show us how to use the mould to make a flower vase.

Use closed captioning.