Frequently Asked Questions on KELATE®

KELATE® is range of highly reactive water reducible chelating polymer for rust passivation on rusted steel which has been hand or power cleaned, or blasted.

The KELATE® consists of different products designed for specific applications:

  • KELATE® MR6: concentrated (needs to be diluted with water before application)
  • KELATE® MR6D (diluted): ready to use
  • KELATE® MR138: provides extra physical barrier (ready to use)
  • KELATE® MR80: for high temperatures (40-60°C)
  • KELATE® Wax: active water based wax system (ready to use)

KELATE® is not a substitute for primer coating. It works as as surface treatment to passivate and stabilize (residual) rust

KELATE® neutralizes the corrosion process. It reacts quickly (reaction time is +/- 3 hours) with the rust and transforms iron oxides into a stable and insoluble blue-black metallo-organic complex which is ready for painting after reaction.

The reaction is characterized by the surface turning to a blue-black colour.

KELATE® effects a thorough chemical passivation of the substrate and makes it a sound base for the application of coating systems.

KELATE® can be applied on any rusted surface which has been mechanically brushed.

It will also react with mechanically activated steel like blasted (not rusted) steel.

KELATE® is a surface treatment. It is not a primer or a paint. The treated surface must always be protected by a suitable paint system.

The limited thickness (10-15µ) of the metallo-organic complex formed by KELATE® will usually not compensate for the roughness of the rusted surface.

KELATE® will passivate the residual rust but an adequate coating proportional to the roughness of the substrate is required to give full protection. Usually, on rusted surfaces, a coating thickness of 50 microns can be considered as the lower limit.

But as KELATE® passivates and stabilizes (residual) rust, it is a guarantee for a longer shelf-life of the subsequent primer. Since residual rust can encourage further under film corrosion, Kelate® will help to protect subsequent coatings from the damages of rust.

Additionally, KELATE® is an excellent adhesion promoter for subsequent coating systems.

And contrary to most chemical treatments of the rust, it is not necessary to wash the treated surface with water before the application of the first coat of paint.

Last but not least, KELATE®MR138 will give additional thickness (20-30µ) and is thererfore recommended in applications where overcoating after 48 hours is not possible and/or in combination with paint systems with limited coating thickness.

KELATE® is formulated to react quickly with rust and mechanically activated steel like blasted steel.

Blasting steel to white metal provides an excellent substrate for painting. But a freshly blasted surface is highly reactive and will rust quickly once exposed to humidity, dew or rain.

KELATE® may also be applied on superficial rust such as the one that forms very quickly after blasting.

Applied on blasted steel, KELATE® will protect the investment in high quality surface preparation.

Non-reactive surfaces covered with Kelate will show very quickly no colour change and need to be cleaned and rinsed off (with water or methylated spirit)

Apply KELATE® on a rusted surface which is clean. Remove oil and grease before brushing.

Loose rust and mill scale are removed by metallic brush, abrasive disk or paper.

KELATE® has been designed so that it will react and stabilize (residual) rust on CSt2-DSt2 surfaces.

When the surface is blasted to Sa1, KELATE® will react and stabilize the remaining light rust.

Using KELATE® can therefore prevent from going to costly Sa2 preparation.

In heavy industrial and marine atmospheres, rust always contains soluble salts; these surfaces must be washed down with clear water before KELATE® treatment.

KELATE® will react quickly (in less than 3 hours) with rust and activated surfaces such as blasted steel to transform them into a stable and insoluble blue-black metallo-organic complex.

If no colour transformation is observed, it means that the surface is not reactive and needs to be cleaned and rinsed off (with water or methylated spirit)

We do not recommend a second coat of KELATE® before painting.
Reason is that the second coat has no chance to react with the steel substrate. The reaction with iron oxides is essential to form insoluble complex and provide the passivation.
This is why KELATE® has to be used as a surface treatment solution and not as a primer.

KELATE® is a waterborne system which is overcoatable in normal drying conditions after minimum 3 hours. Normal drying conditions mean temperature above 15°C and relative humidity below 80%. In general a drying time overnight is recommended.

Solvent-based paints usually applied on steel surfaces are compatible with KELATE® . These may be paint systems based on alkyd, modified alkyd, epoxy, polyurethane or vinyl.

  • Minimum application temperature is 5°C.
  • Maximum application temperature is 35°C.
  • Maximum service temperature without coating is 90°C.

Short term exposure up to 30 minutes at 120°C could be considered.

KELATE® MR6D can be used as a pre-treatment to stabilize residual rust on steel reinforcements in concrete.

During the application of KELATE® MR6D, precautions have to be taken to avoid any splash on the concrete surface itself. Areas outside the portion to be treated should be masked or rinsed immediately with water if splashed.

After drying, the application of KELATE® MR6D must be followed by a suitable protective coating, as usual.

Thanks to its unique formulation technology, KELATE® differs from many other rust converters on the following key properties:

  • Water based – Zero VOC
  • Quick reaction time (less than 3 hours)
  • Provides full rust passivation on adequate surfaces (CSt2-DSt2 standards)
  • Allows to save on costly additional mechanical surface preparation
  • High coverage: 20m² per litre.
  • Requires only one coat without excess.
  • Can be applied on humid surfaces
  • Coatable after 3 hours
  • Does not contain phosphoric acid which usually leaves acidic residues on the surface
  • No brush marks (thin and homogeneous coat)
  • No need to rinse off the surface after reaction
  • Not irritant nor corrosive
  • Long shelf-life (12 months)