Iron oxide pigment (deep red) is used as dye or colourant in various applications, including ceramic, paint, concrete, coating, ink, leather, plastic and rubber. This dry pigment powder with an iron oxide base can be mixed with a binder to tint glaze and varnish or make paint.
Iron oxide is used to coat the particles in cement and mortar/plaster. You can achieve a good colour using 4% by weight of oxide to the weight of cement. At 8-10% saturation occurs and no additional benefit is achieved.
Iron-oxide mixing ratio for concrete/plaster/mortar, follow these steps:
- Determain the weight of the cement and use the table below to calculate the amount of oxide to use (based on 4%).
- Mix thotoughly with aggregate/sand and 1/2 the water. Mix thoroughly prior to adding cement and remaining water. Adequate mixing must occur to ensure full dispersion of colour.
- To achieve consistant colour ensure all batches are identical. Ideally a sample should be approved before undertaking the job.
|BAG CONCRETE MIX||25kg||3kg||120g|
The above ratio is an indicative guide. Therefore, you need to determine your own mixing ratio by doing a few tests before proceeding with your job.