The use of Zinc Silicate – Presentation at the Australasian Corrosion Association (ACA) Annual Meeting

While not CSI’s area of expertise, we attended a very interesting presentation at the ACA Annual Meeting about the preparation and application of Zinc Silicate. This presentation got us thinking …

In this case, a steel bridge had some serious issues only a few years after construction, in terms of the longevity of the corrosion control application of Zinc Silicate.

Here is a description of Zinc Silicate from Corrosionpedia … “A zinc silicate coating is a type of coating that gives corrosion protection to surfaces such as steel. As the name implies, this type of coating contains large amounts of zinc metallic dust mixed with a zinc silicate binder, and also contains high-build polysiloxane or a hybrid topcoat and primer made from inorganic zinc.

The use of this type of coating and formulations to achieve steel protection has been well known in the protective coating industry. Almost all of the zinc-based coatings are created with either epoxy resin binders or inorganic silicate.

Zinc silicate coatings are also known as inorganic zinc-rich coatings or paints because they usually contain a zinc silicate binder”.

Through much forensic unraveling of the process that had been followed when applying the layers of preparatory coatings and the Zinc Silicate; it transpired that not enough air had circulated around the steel framing to allow a full drying out to occur within each layer.

The layers were applied in a shed without sufficient fans to dry each layer (possibly in winter as well, although we are not certain of this fact).

The specifications for this particular silicate had identified ambient drying conditions.

While the recount of the issues might not be 100% correct, the overwhelming message given to us by the presenter was that the correct specifications were not followed to the letter, and the consequences were immensely expensive.

It is a timely reminder in our industry, that specifications (and limitations for that matter) are produced for a reason and come from much scientific research into the product.

These specs need to be read and understood by all operators/applicators of products or tools.

While it is possible to push some machinery and tools to achieve beyond their limitations, this has to be achieved by research and experimentation that can be verified, before being offered commercially.

There is also the opportunity to have your research independently checked, which is a great reassurance not only for your business but also your customers.

We will certainly be reading specs with even more care and commitment from now on.  CSI are motivated to be innovative, but it is important to do so while knowing your constraints!

Feel free to contact the team at CSI a line if you want to have a chat about sticking to specifications or even if you want to talk non-destructive testing!!!

www.csiscan.nz or phone 0800 33 7767.