Ensuring Quality and Preventing Corrosion

To ensure the quality of our high-quality coating, we carry out various quality checks. One of the checks we can perform is the so-called Holiday Test. With the help of calibrated equipment, we check for small, invisible holes (pinholes) in the coating.

Everything to prevent corrosion

In our coating department, where we can blast, wet paint, and powder coat, everything is aimed at preventing corrosion. At Straatman Dredging & Construction, we work according to strict procedures and standards and can wet paint in accordance with the ISO12944 standard up to category C5. We deliver high-quality coating where all relevant checks are recorded and eventually summarized in a coating certificate.

The real quality is in the details. And that’s exactly our specialty at Straatman Dredging & Construction! Small holes, pores, or craters in the coating are not always visible. Unfortunately, they can be there, often caused by air bubbles, dust particles, or if the paint substrate does not flow nicely locally. If this occurs, there is a defective coating, and early corrosion can occur. At Straatman Dredging & Construction, we do everything to prevent early corrosion as well.

Prevention is easier than repair

We prevent deviations in the coating by performing the following checks:

• Check for the presence of dust
• Check for cleanliness after blasting
• Measure salt content
• Dew point checks
• Continuous monitoring of temperature and humidity
• Layer thickness measurements

Positive results from these checks indicate that the chance of small holes, pores, or craters is negligible.

To demonstrate that all steps in the coating process have been properly completed, we can use our calibrated equipment to check for so-called pin holes in the paint surface. We call this the Holiday Test and is often required in the specifications of our maritime clients.

At Straatman Dredging & Construction, we use the well-known wet sponge technique: A sponge is set at low voltage, where the voltage is adjustable depending on the dry layer thickness. When the sponge slides over an imperfection in the coating, the liquid penetrates the substrate, which creates an electrical circuit and sets off the alarm. Invisible holes become “audible” this way.

Successful tests

For this specific project, we were allowed to coat another offshore quick release hook and we are proud to report that we have completed all tests and quality checks.