CASE STUDY
TRANSFORMER OIL LEAK REPAIR
Repair of transformer tank and inspection cover oil leaks
Industry: Power
Application: Transformer Oil Leak Repair
Products: Belzona 1161, Belzona 9341, Belzona 5831
Customer Location: : NSW, Australia
Application Date: Apr 2026
PROBLEM
An electricity distribution network operator was experiencing a significant oil leak from one of its transformers. The unit, originally installed in the 1970s, had been leaking for an extended period, with leaks identified at the bolted flange joints of the transformer tank and bolted inspection covers.
These areas had suffered corrosion, along with degradation of the gaskets and sealing surfaces. At the time of assessment, the transformer was losing approximately 1,000 litres of oil every six weeks, resulting in substantial ongoing costs.
The leak also posed serious safety and environmental risks, as transformer oil is flammable and can contaminate the surrounding environment. Additionally, the condition of the transformer led to increased maintenance requirements and a heightened risk of unplanned outages, shutdowns and repairs, impacting overall network reliability.
Leaking transformer tank flange joint
Corroded transformer inspection cover flange
APPLICATION
Following an initial inspection and assessment of the repairs required, it was decided to use Belzona’s transformer oil leak repair system to seal the leaks and restore the integrity of the affected areas.
The transformer was drained, scaffolded, and high-pressure hot washed prior to the commencement of works, ensuring safe access and removal of bulk contamination. All targeted repair areas were further cleaned and degreased using Vegesol to eliminate residual oil contamination and prepare the surfaces for treatment.
Cleaning of surfaces with FP29 Safe Solvent
Abrasive blasting was then carried out to achieve the required surface profile and remove corrosion from critical sealing interfaces, including the main transformer lid flange and associated bolts, and three individual inspection covers, including flanges and bolts.
A final pre-clean was completed using FP29 Safe Solvent to ensure all surfaces were free from contaminants and ready for application.
Abrasive blasting was carried out to achieve the required surface profile and remove corrosion from critical sealing interfaces
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All flange bolts were individually sealed (top and bottom) using surface tolerant Belzona 1161, preventing oil migration along bolt threads which is a common leakage path. This process required approximately one full day to complete due to the number of fasteners involved. Following an overnight cure, a light whip blast was performed on the cured Belzona 1161 and adjacent flange surfaces to optimise adhesion for subsequent applications.
Belzona 1161 was applied to the main flange and reinforced with Belzona 9341 Reinforcement Sheet, forming a durable, flexible sealing barrier across the joint. A final protective coating of Belzona 5831 (ST-Barrier) was applied to complete the system, providing long-term environmental protection and sealing performance.
Sealing of bottom flange bolts with Belzona 1161
Sealing of top flange bolts with Belzona 1161
Flange bolts after light whip blast
Transformer inspection cover flange after surface preparation
Application of Belzona 1161 to lid flange
Lid flange repaired and sealed with Belzona 1161
Belzona 1161 applied to main flange
Belzona 9341 Reinforcement Sheet
Completion of flange joint sealing
Top flange joint bolts repaired and sealed with Belzona
Bottom flange joint bolts repaired and sealed with Belzona
Application of Belzona 5831 (ST-Barrier)
Lid flange repaired and sealed with Belzona 5831 (ST- Barrier)
OUTCOME
The repair was completed within a three-day period, including application and curing, allowing the transformer to be safely returned to service over the weekend and minimising disruption to network operations.
Following return to service, the transformer was inspected and found to be performing as expected, with the previously identified oil leaks effectively sealed.
Overall, the solution delivered a significant reduction in oil loss, eliminating the need for frequent top-ups and ongoing maintenance associated with the leaks. This has improved asset reliability, reduced environmental and safety risks, and extended the operational life of the transformer.
Transformer inspection cover flange oil leak repaired and sealed with Belzona
Products
Belzona 1161 (Super UW-Metal)
A 2-part composite material for metal repair and resurfacing based on a solvent-free, surface-tolerant epoxy resin reinforced with silicon steel alloy.
This composite material is specifically designed for application to wet and oil contaminated surfaces, as well as for underwater applications. It is easy to mix and apply without the need of specialist tools and can be machined using conventional tools.
Belzona 5831 (ST-Barrier)
A 2-part epoxy coating which once cured forms a barrier coating for the protection of equipment operating under immersed conditions or in contact with aqueous solutions.
About Rezitech
Established in 1968, Rezitech is the sole Australian Distributor for Belzona. Rezitech offers a comprehensive range of industrial protective coatings and epoxy metal repair composites to many different industries including: oil and gas, mining, power, water and waste water, pulp and paper, marine, manufacturing among others.
We value growth and innovation within the maintenance solutions industry
Our Mission
To provide industry with easier maintenance solutions that provide cost effective, efficient and long lasting results for our valued clients. To provide an integrated industry service by striving for Rezitech being a truly complete solutions provider!
Our Values
We value the needs of our clients and place a huge emphasis on providing specialist skills and knowledge.
From engineering to fitting, blasting or coating to sales, administration and customer service, we highly value our organisation and encourage diversity andgrowth to benefit our client and our team of people.
Our Vision
To strive for excellence in our delivery of high quality industrial maintenance solutions. To be our clients’ preferred choice when it comes to solving all of their maintenance and new pump needs while helping to reduce their carbon imprint.
Health and Safety
Rezitech is committed to ensuring the health, safety and welfare of its employees, contractors, visitors and customers who may be affected by Rezitech’s operations. We strive to pursue standards of safety that meet and exceed statutory duties.
Community & Environment
While providing solutions for our clients Rezitech focuses on identifying ways to improve business environmental performance while increasing productivity and reducing costs of production for the benefit our clients and hence the community.
The Future
To continue to strive for excellence! To continue to lead the way in industrial maintenance solutions and services and provide our clientele with high quality, complete and reliable products and services.
Rezitech’s mission is to make its liquid ring vacuum pump expertise available to sugar mills, paper mills and process industries worldwide. We currently export to:
- Fiji
- Thailand
- Mauritius
- Indonesia
- United Kingdom
- Phillipines
- Malaysia
- New Zealand
- Papua New Guinea
We are constantly on the look out for new export opportunities and new countries to export to Rezitech places an emphasis on the development of export business worldwide.
For further information on a Flowtech Distributorship please contact us.
