A coating conundrum
19 July 2016
While it is always beneficial to know what could have been done differently when something goes wrong, this knowledge often doesn’t help resolve the current predicament. This is especially pertinent in the maintenance industry, where much of an engineer’s time is spent combating corrosion issues that could have been prevented with pre-emptive measures, as Peter Crossen of NCH Europe explains
Many businesses operate under the impression that rust is an unavoidable consequence of production. Whether it’s flash rusting on manufacturing infrastructure or pipes corroding in chemical manufacturing plants, there’s often an attitude of acceptance to the onset of rust. It’s not until rust has begun to seriously impede production that action is taken.
The global cost of rust management and repairs across industries reaches a terrifying total of US $2.2 trillion, according to the World Corrosion Organisation, a large percentage of which could be saved using proactive treatment.
It is understandable that much of the rust in factories goes undetected until it’s too late. Thorough inspections can be difficult to complete regularly and even the most experienced engineers may find themselves missing problem areas. Unless it’s a case of flash rusting, it’s even possible for internal engineers to fail to notice some rust build up at all; becoming blind to it as it creeps in.
The best advice for maintenance engineers is to invest in an integrated approach to asset treatment that prevents corrosion from creeping onto surfaces. To achieve this, we developed a comprehensive rust treatment programme that delivers a three-pronged attack to rust involving pre-treatment, encapsulation or rust removal, and a protective coating (http://ncheurope.com/en/rust-removal-and-rust-prevention).
Once loose surface rust has been removed, using an industrial degreaser can ensure that no contaminants are left behind that will render further treatment futile. This pre-treatment step is arguably the most important.
Rather confusingly, rust removal solutions form the second step. Although the loose rust has been banished, the effects of underlying corrosion will still be present and could pose a risk to the integrity of the infrastructure. By using an effective rust treatment product this corrosion can be prevented.
To keep rust from returning it is essential that the surface is maintained with a product that can prevent moisture penetration causing corrosion on the substrate. By painting on either a temporary or permanent protective coating after removing rust, even the most susceptible surface can avoid corrosion.
To this end, we have developed Salvage 2+. Made of a durable composition of resin-based epoxy mixed with micro aluminium and glass flakes, the product combines the encapsulation and protection stages. It can be applied directly onto rusty surfaces to encapsulate and stop rust in its tracks.
Salvage 2+ has also been subjected to extensive scribed hot spray testing, achieving 3000h before corrosion sets in. This is six times as long as some protective coating products on the market.
In one of our customer applications, a plant manager was considering replacing two 10-year old storage tanks that showed signs of corrosion. In this case, it would typically have cost £5000 to replace the tanks, in addition to costs incurred due to downtime, fitting and transport. Here, we first removed the corrosion, taking it back to base metal, used ultrasound equipment to ensure the tanks were structurally sound and then completed our three-stage treatment programme using salvage 2+ at a cost of around £600 plus labour. The process was quick and easy and no downtime was necessary.
Hindsight may be both a blessing and a curse, but if you take the steps to enforce a regime of rust prevention looking back will only be a positive experience.
Peter Crossen is VP of water, energy and maintenance solutions provider NCH Europe’s Maintenance and Partsmaster Innovation Platform