The Flaking Paint Matter

Paint flaking from a surface is one of the most common paint defects, seen the world over in many environments and substrates.

Located along some of the major thoroughfares of Dublin, Ireland, may occasionally be found some cast iron poles many of which are embossed with 'S.D.R.D.C' 1912 which refers to South Dublin Rathdown District Council. These poles, occasionally mistaken for telegraph poles or indeed street lighting poles are actually sewer vents, the purpose of which was to vent noxious sewer gases to the atmosphere. One such sewer vent is located along the Nangor Road in South Dublin and recently, consideration was been given to removing over one hundred years of flaking paint and restore the vent to its original emerald green colour.

What was the question?

The question which required an answer was 'did any of the previous coats of paint contain lead' as if they did, some special care would be need to protect contractors and the environment. Our laboratory sent a chemist to site who carefully removed specimens of paint. The paint specimens were small, measuring approximately 4 mm square, however with the correct chemical analysis protocol, we get to the correct answer.

The paint samples, were brought back to the laboratory and booked in. The samples of paint were cast in an epoxy resin and gradually ground and polished to reveal the individual paint layers. The technique which is used is called metallography and is used not only used in the forensic examination of paint films, but also in the examination of metals and electronic components such as circuit boards where the technique is used to examine both electronic components and soldered component joints.

The resin mounted and polished paint samples were analysed using Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). This technique allows us to carry out targeted analysis on specific points within each paint layer and in so doing, we can determine the elemental composition of each layer within the total paint film.

What was the result?

Targeted SEM-EDS analysis on points within the paint layer showed the presence of Titanium, Barium and Chromium. The presence of these three elements being due to the pigments used to make the paints. As expected, Iron was also present, being due to the effects of corrosion, however, no Lead was detected.

Through detailed analysis carried out using highly advanced analytical equipment, our laboratories could arrive at a scientifically valid result which answered the question without hesitation.

When it comes to paint analysis, our laboratory has decades of expertise, so take the unknown out of your paint questions and contact our experts.