After the success of my ferrocement raised garden beds, I wondered whether I could make a workable kitchen bench top using the same material. In this case I would use white portland rather than GP to lighten the surface. We might add a bit of orange oxide to warm the colour, although the white portland already has a nice yellow tint it seems.
Tobin and I made a mould using some plywood and 35x70mm pine. The ends are movable and have through bolts for tensioning. The bolts are coated in vaseline to aid in removal, the nut will remain in the slab and might be used for mounting.
The mould has a piece of heat shrink film over the ply which I heat gunned to smoothness before pouring. The hope is that I can avoid the messy and time consuming sanding process.
The mix I used was designed by Norwood and includes an admixture which reduces the amount of water required for workability.
The mortar was poured into the mould and spread with a trowel. When I started I lifted the wire mesh (under considerable tension) using a block of wood over the top with some wires looped through so as to prevent the mesh from being forced too close to the bottom, which will be our top face. Once the mortar was poured and spread the wire was removed and the mesh sank into the mixture, hopefully to roughly the centre of our 2cm thick slab.
I placed a vibrator made from an 'interactor' vibration motor and a 12V ac power supply on the surface. This helped to shake out any bubbles in the mixture. The slab is now left to cure for the next week.