By Ben Rowland
One of the most important, and most common, questions raised when assessing the condition of an existing water tank is whether or not it is a candidate for overcoating, or if will it be necessary to blast clean the tank back to the bare substrate.
This is a simple question with a multitude of variables and answers. Some of the variables include: budget, tank site, condition of the existing coatings, the type of existing coatings, desired life expectancy of the coating system to be applied, desired coatings to apply, so on and so forth.
Based on the variables, we are left with many answers that create more questions: We have enough money to blast, but is it necessary? We don’t have enough money, so what can we do? We can’t blast without shrouding the tank or we’ll paint every car on the road next to us. The existing coatings have lead, so will this cost to blast and contain exceed our budget? Will the type of existing coating allow an overcoat? Do we intend for this paint job to last 10 years or 20+ years?
It’s easy to see that each tank is unique and comes with its own set of considerations. As a rule, blasting will typically yield better long-term results, as you are starting from scratch and eliminating many of the unknowns. Remember, the adhesion of what you apply is only as good as what you paint over. That being said, existing coatings that were applied properly and have aged well can provide a more than adequate surface to overcoat.
If you expected to find a black and white answer and some clarity on the subject when you started reading this blog, I’m sure I’ve disappointed you. It was not my intent to answer the question so much as it was to call attention to the complexity of this seemingly simple question.
It is only through experience and exposure to tanks in varying conditions that we can gain the insight needed to properly assess what the most efficient solution to repainting a tank will be. With almost seven years in this industry, and hundreds of tanks inspected and witnessed through the repainting process, rarely am I involved in a project that does not have at least one consideration that is exclusive to that particular job.
Myself, and others at Induron, expect to be that wealth of knowledge that can best specify cleaning standards and coatings systems required to give owners and engineers the answer to a not so simple question.
Founded in 1947, Induron manufactures high performance coatings that serve a range of industrial applications, including the wastewater, transmission and distribution and groundwater storage industries. Learn more about us at Induron.com.