STEP-BY-STEP INSTRUCTIONS:
1) First get your equipment and space ready
2) Next, using a measuring jug, pour the required amount of water into the container that you are going to plunge the hand/foot into (or leave the water in the jug and mix in there, so its ready to pour quickly into the container or onto the body part after mixing). Check the water temperature is 20-23 degrees.
3) Next measure the correct weight of alginate into another container using ratios given above
4) Empty the alginate powder on top of the water and start the timer. Use the knife or flat spatula in figures of 8 motion to carefully bind the powder and water together. If mix is lumpy after the binding stage, mix with a hand blender or whisk until creamy smooth. You have two minutes of mixing time.
5) Powder starts white, then after adding water, it goes bright pink. 2 mins from adding the powder to the water, its ready to mould. So plunge the hand or foot etc in, making sure the hand or foot doesn’t touch the sides of the container. (Or pour the alginate onto the body etc for other casting processes). Wiggle the hand/foot a little to let air bubbles escape then hold still when the mix starts to turn pale pink as it has started to fully set. Keep still for a further minute until the alginate is fully white before wiggling the hand or foot out.
Your alginate mould is complete and ready to cast:
6) Where possible, alginate impressions or moulds should be cast immediately. If you have to store them before casting, place in a moist atmosphere e.g. an enclosed polybag with a damp tissue and try to cast within 24 hrs. Don’t store it in water.
7) The next step is to pour casting plaster into the empty alginate mould and wiggle/jiggle the plaster in the mould to release air bubbles. See casting plaster instructions for more details but remember NEVER PUT A BODY PART IN CASTING PLASTER as it sets hard and can cause burns. Only put body parts into alginate.
8) Finally, after the plaster is set in the mould, cut the alginate away from the plaster carefully using a craft knife. Work carefully to avoid breaking parts of the cast off. If you find you have holes in your plaster casting, this is due to trapped air bubbles and they can be filled using mixed plaster. Fingers can be stuck back on after drying with a suitable DIY glue
9) You need to allow your plaster model to dry for at least one week in a warm room before painting or sealing with acrylic paint/varnish. If you paint too soon, the moisture will still be evaporating from the plaster and will spoil the paint surface.
Instructions For Casting Powder (Stonecast):
Add 1kg powder to 500ml water. Always add powder to water only. Mix thoroughly to a creamy paste. Using less water makes plaster harder, more water makes the plaster softer.