Transformer Painting Featuring Radiator Flow Coating
Substation Structure & Transmission Tower Painting
Insulator Coating & Cleaning

USM-Permashell specializes in cleaning and painting high voltage electrical equipment, serving the Canadian utility industry for over 10 years. We understand the safety and operational requirements of substation work, and our personnel are trained for work in energized substations.


Electrical transformers represent very large capital investments, and they are designed for life cycles of 50 years or more, but the OEM paint jobs just don't last that long. Sooner or later they need to be repainted for protection against corrosion damage.

When it comes time to repaint transformer radiators, you have two choices:

The Right Way - Flow Coating
The Wrong Way - Spray Painting

The Wrong Way
Spray Painting
The Right Way
Flow Coating

Spray painting just doesn't get the job done. In fact, spray painting may not cover any more than 50 to 75% of radiator surfaces, camouflaging the corrosion damage and leaving your operations vulnerable to electrical failure. It's the Wrong Way.


Flow Coating is the only complete and long-term cost effective way to do the job.

Similar to a factory immersion finish, Flow Coating is applied on location in the substation without dismantling the equipment and if necessary with little or no interruption of service.

Flow Coating provides complete coverage of 100% of radiator surface area, including the backsides and restricted surfaces of the fins, tubes and stabilizer bars, as well as the joints, seams and hidden areas deep within the radiator banks that are not accessible by any other painting method.

Where rust has formed on inaccessible radiator surfaces, a special rust removal and neutralizing solution is applied by Flow Coating to chemically neutralize the rust, and passivate it for encapsulation with subsequent coats of corrosion and weather resistant paint.

Also, where old coatings are blistered, flaking and peeling on inaccessible surfaces, they are stripped from the tube surfaces with a heated chemical stripping compound by the Flow Coating process. This is followed by treatment of the bare metal surfaces with a chemical surface treatment solution, and refinishing with multiple coats of corrosion and weather resistant paint, to provide a replacement coating system that will be trouble-free for as long as possible.

Where equipment is exposed to contamination with soluble salts such as chlorides, sulfates or nitrates, invisible residues left on surfaces will absorb moisture through coating films, causing blistering and premature coating failure. Decontamination with
a soluble salts removal solution is specified for insurance against salt-induced coating failure.


Most substation structures and transmission towers are constructed of hot-dip galvanized steel. Depending on the quality of the galvanizing and the environmental exposure, galvanizing generally lasts from 15 - 50 years before the zinc coating is eroded to the point where corrosion of the base steel begins to take place, and it is very important to recognize when this begins to occur. A protective layer of paint over aged galvanizing acts as a barrier between the remaining zinc and the environment, slowing down the rate at which the zinc is sacrificed, and allowing it to continue to protect the steel substrate for a much longer time.

Changes in the appearance of the galvanizing are an indication of its life expectancy. As galvanizing weathers, it loses its brightness and darkens due to the formation of zinc corrosion on the surface. When it becomes dark grey, it is a general indication that much of the zinc layer has been eroded away. This is the signal that maintenance painting is due, because surface preparation, which is a major factor in the cost of painting these structures, is fairly moderate at this point.

When the surface becomes reddish-brown, the zinc-iron alloy layer, that was formed between the zinc and the the steel substrate, has been exposed by the erosion of the zinc, and a new barrier is needed to avoid jeopardizing the integrity of the structure.

Doing maintenance at the right time has measurable and significant cost savings. Maintenance painting at the right time extends the protection of the original galvanizing, and if done properly with the appropriate coatings, doubles the service life of the structure. Repeated maintenance painting later on will further extend the service life of the structure.



When flashovers occur, it can cost much more than replacement or repair of the damaged insulators or bushings. Flashovers can cause sudden, unexpected power outages that can result in production stoppages or interruptions of customer services that can easily cost thousands or even millions of dollars.

Flashovers due to surface contamination and wildlife contact can be prevented by the application of silicone High Voltage Insulator Coating on the surfaces of insulators and bushings.

Proper surface preparation is essential for good adhesion of HVIC. If necessary, USM-Permashell cleans insulator and bushing surfaces by gently blasting with a very soft, fine powdered limestone abrasive that does not damage glazed surfaces. The light dust film of this non-toxic, agricultural-grade limestone powder is safely blown away with high-pressure air. And unlike corncob abrasive that is often used, our cleaning compound leaves no corrosive residue on other substation apparatus, and no mess in substation yards.


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Insul-Mastic Coatings
Insul-Mastic 553-D | Insul-Mastic 4010