What you need:
- Flat surface board or surface to work on
- Crack foam filler (expandable)
- Hand saw/knife
- Silicone rubber mould product (available at art shops)
- Small paintbrush
- Small hammer
- Tile adhesive
- Steel trowel
- Fine river sand
- Building stone (12mm)
- Cement powder
- Cement oxide
- Any Container
- Damp river sand
What to do:
- Shake the Foam filler can vigorously to mix contents (as indicated by the manufacturer instructions).
- Remove cap carefully, holding can away from face. Carefully screw the nozzle fully onto valve. (Refer to the manufacturer’s safety instructions).
- Holding the can upside down, spray a small amount of foam onto the flat surface – try to do this in a circular movement to create a rounded shape for the rock but it does not have to be a perfect circle
- Leave the foam to dry for 24hrs
- After 24hrs, you will notice that the foam have grown bigger and formed a rugged looking circular shape. Take a hand saw or a knife, cut off the back of the foam mould (the cladding needs to be flat at the back because it will be attached to the wall)
- Mix the Silicone rubber mould product according to the manufacturer’s instructions.
- Place the foam back onto the flat surface. Use a paintbrush to spread the silicone rubber mix onto the top as well as on the sides- making sure you are creating a lip.
- Leave the newly painted foam to dry for at least 24hrs.
- When dry, peel off the dry latex rubber from the foam. This rubber will form the Lava rock mould.
- Mix 2 scoops of fine river sand, 1scoop of 12mm building stone, 2 scoops of cement and 250g oxide with enough water to form a runny concrete mixture. This mixture will be enough to do 3 moulds, so for a larger volume just simply stick to the ratios 2; 1; 2 and for the oxide – follow the manufacturer instructions ratio.
- Fill up a container with damp river sand; make a hole in the middle then place the rubber mould inside. The river sand acts as a support for the mould.
- NB: Instead of doing the step mentioned above- you can also dig a hole in the ground and place the mould in it
- Pour in the concrete mixture into the rubber mould until it is completely full. Use a steel trowel to agitate it and leave it to dry for at least 24hrs
- When the mould has completely dried, peel off the silicone rubber mould to reveal a concrete lava rock to use for cladding.
- To attach you cladding to the wall, mix a bit of tile adhesive and apply onto the flat part of the rock cladding.