- Forced Action Mixer or Paddle Mixer
- Suitably sized mixing vessel (1.5 to 2 times the mix size)
- PPE Listed below
- Bucket trowel or similar
- Clean bucket to weigh out water
Personal Protective Equipment
The following Personal Protective Equipment is advised during the mixing and use of the Premix Kit;
- Gloves or Nitrile Gauntlets
- Eye Protection (goggles or glasses)
- Disposable Overalls
- FFP3 Dust Mask
- Empty the contents of the bucket into your mixer/mixing vessel. DO NOT ADD THE FIBRES
- Weigh out 3.12Kg or 3.12 litres of water
- Mix the dry powered ingredients without adding the water. DO THIS ON A SLOW SETTING to reduce dust dispersion. Mix for 2 minutes.
- Add approximately 3/4 of the water
- Mix for 15 minutes
- After 15 minutes of mixing check the consistency of the mix. Signs that the mix is ready are as follows;
- Air is bubbling up through the mix and bubbles are popping at the surface
- When a trowel is run through the mix, the mix self-levels and closes up within seconds
- Add more water in small quantities as necessary until the desire consistency is reached.
- Take a small portion of the mix to pour into the mould for a fibre free or half fibre facecoat. Spread this evenly over the base of the mould. for 1 metre square of concrete worktop this equates to 8.5kg of mix at a thickness of 4mm.
- Add the fibres to the remaining mix and mix on a slow speed setting for as little time as necessary to ensure they are dispersed evenly throughout the mix.
- Pour the mix carefully over the facecoat already applied and proceed according to the Basic Concrete Casting Instructions PDF.
Basic Concrete Casting Instructions
Concrete by nature is heavy so we recommend that for any larger decorative concrete panel items such as tabletops or countertops that a maximum thickness of 20mm is designed. To create the appearance of thickness we recommend that a “lip” be formed around the perimeter of the item. Following is the basic method by which this can be achieved.
1 The Basic Formwork
The basic formwork is created using a base material, strips of formwork and reinforcement blocks. Melamine is recommended as the material. Hot glue is recommended as the adhesive.
Basic Concrete Casting Instructions
2 The First Cast
After mixing your first batch of concrete pour into the mould. This should ideally self-level after a period of a few minutes. Each mix should be poured on top of already poured concrete to ensure a homogenous layer.
Once the base has been fully poured to a thickness of approx 20mm, the mix should be pulled up the outer formwork or “lips” to create an all important coating.
We recommend using the Concrete Lab Premix Kit for the concrete as it has all the correct ingredients and has a fool-proof methodology for imperfection free concrete.
3 Final Formwork & Second Cast
After 2-4 hours the inner formwork can be constructed using melamine strips and hot glue. A caulk bund should be incorporated as located in the images below to prevent leakage of the secondary mix.
Once the inner formwork is in place and secure the secondary mix can be carefully cast.
Once the cast is complete the concrete should be covered with plastic sheeting to prevent moisture loss. This is imperative to ensure high and early strength gains.
It is also recommended that the concrete be cured at 21degC and no less than 18degC. Heated blankets should be considered if the workshop temperature cannot achieve this.
Assuming that step 4 has been achieved, demould can take place after 24 hours. Carefully remove the formwork to ensure that you do not damage the concrete before full strength has been achieved.