Methodology & Technical Discussion
Stage One
Rust Conversion
Dealing in treating rust is a very risky endeavour for a paint company. There are very few companies that attempt to coat where rust is present without sand blasting or machine abrasion surface preparation.
We have trialed many products and are comfortable in only one system, which is explained in detail.
There are many tannic acid based rust converters on the market – Fertan, Neutrarust, Rust Kill, Endrust, Ferronite, and so the list goes on, but they are basically tannic acid solutions designed to pour onto the rust, which then turns black (some versions turn blue), which donates the conversion of the mixed iron oxides and hydrated iron oxides into an iron tannate.
They then apply a zinc rich primer (an extremely dense, oil based primer which contains a high level of dust dust/zinc flake) over the top, followed by a suitable topcoat which, one has to say, is quite a lengthy and extremely costly procedure.
However, in our opinion, there are a number of problems with this approach, including:
the iron tannate molecule is relatively large and rust can re-occur in the presence of water/moisture and oxygen, plus the zinc primers (and subsequent top coats) do not always adhere well to the so called black iron layer.
Our rust converter of choice is designed for application over bad rust only, and the coating converts all the mixed iron oxides, plus hydrated iron oxides, into an iron phosphate, which is an irreversible reaction.
The really beautiful part of this approach is that there is absolutely no interface or distinct transition from the converted layer to the paint film (as occurs with the tannate approach described above) – everything takes place within the paint film itself and the longer the paint takes to dry the better and more complete is the phosphating action.
Stage Two
Rust Inhibitor Etch Primer
Once rust has been converted to a stable metal phosphate within the paint film, a coating of our Rust Inhibitor, our rust preventative primer coat, is applied.
The coating is the “twin sister” to our Rust Converter, which is designed mainly for application over well rusted steel. When the primer cures into an abrasion resistant skin it is impervious to further rust.
The primer coat (Rust Inhibitor), like the Rust Converter, is an acrylic based primer designed for application over the rust conversion layer.
Stage Three
Thermoshield Ceramic Coating
Following rust conversion and primer, the water based THERMOSHIELD adheres to the water based rust converter and etch primer with outstanding results.
The Thermoshield ceramic coating contains strong rust inhibitors. High levels of zinc phosphate and an ‘anti flash rust’ solution is added to the composition.
Thermoshield is applied to yield a minimum total dry film thickness of 350 micron, making a total paint system dry film thickness of 500+ micron.
This is classified as “high build” which offers maximum protection from elemental exposure and ensures greater life expectancy against the damaging effects of UV.
Following conversion and primer coats, the ceramic coating creates a non permeable membrane that acts to encase the converted metal, eliminating any and all environmental exposure. Ceramics are chemically stable and resistant to highly corrosive environments.
Corrosion ultimately requires water and oxygen following permanent rust conversion. Once the metal is sealed beneath the thick ‘blanket’ of the THERMOSHIELD ceramic coating the metal is no longer able to make contact with water and oxygen.
THUS: The essential elements for rust/corrosion have been eliminated.
Each of the individual products that compromise the paint system that we use are all compatible and acrylic based. Each product contains their own levels of rust conversion or rust prevention.
- Rust Inhibitor (primer) has mild rust conversion and strong etch primer properties
- Rust Converter has strong rust conversion properties
- Thermoshield has high zinc phosphate and ‘anti flash’ rust prevention properties
The end result is a paint system that yields a strong flexible membrane with
THREE levels of specific rust protection (or) prevention with maximum resistance to UV degradation and a minimum Warranty term of 10 years with the ability to prolong the coating life with scheduled maintenance.
