Before you dispose of corroded expensive or irreplaceable equipment – consider repairing and restoring it to original condition using Polyflake.
Developed in Europe and made from chemical resistant highly modified resins mixed with glass flakes, Polyflake can repair, rebuild and protect equipment to original standards at a much lower cost than replacement.
WHAT ARE POLYFLAKE COATINGS?
|Ballast pump for ocean freighter heavily deteriorated by salt water corrosion.
||After grit blasting.
||Corroded areas restored and machined back to original tolerances.
||New life for ballast pump, brought back to new condition.
WHAT ARE POLYFLAKE COATINGS?
These are formulations of glass flakes and corrosion/chemical resistant polyester resins. Compared to other chemical and corrosion resistant resins available, Polyflake is the natural choice. By a controlled polymerisation process the resin is bonded to the original bare metal, and in a three-phase process the corroded or damaged machine parts are restored to their original specifications. The formulation can be varied to produce spray, brush or trowel grades to meet the specific needs of each application, and suit the corrosive, chemical and mechanical conditions to be encountered. Polyflake can be applied to most metal surfaces, concrete, synthetics and substantially increases the operational life of all treated equipment.
- Linings and coatings containing glassflakes show superior resistance to abrasion and impact. They enhance a vacuum bond with the substrate to the extent that no undercutting will occur.
- Because the glassflakes are only 3-4 microns thick, there can be as many as 300 parallel overlapping glassflakes in a 2mm thick lining – thus a very tortuous path is offered to liquid or vapour penetration.
- Examination of underlying surfaces after removal of the Polyflake coatings showed that no under-film oxide had been formed. This proves that the product is highly resistant to penetration of oxygen and other corrosive chemicals.
The flakes also perform two other very important functions:
- Glass flakes control the shrinkage stress normally associated with resins during their cure, and they reduce the co-efficient of expansion of the resin to match closely that of aluminium.
- Coupled with the already excellent adhesion properties, the glass flakes enable the bond with steel to be maintained at temperatures as high as 170 degC.
Why the use of glassflakes?
The principle of using fillers of flakes is to reduce permeability, to protect against chemical agents and to enhance fire resistance. Polyflake uses flakes of C-glass specifically developed for their chemical resistance. These glass flakes mixed with high performance modified resin produce the Polyflake coating materials. Extensive tests have shown that Polyflake coatings substantially protect metal and non-ferrous surfaces, even in severe corrosive environments. Polyflake has been effectively used in immersion conditions at a temperature of 100 degC. Customer evaluation indicates Polyflakes ability to withstand double salinity levels at boiling point.
Machining and surface preparation
First the surface of the equipment is completely grit blasted so corrosion and foreign material are removed before a base coat of Polyflake is applied.
Layers of Polyflake reinforcement coating are then applied to rebuild, fill pits and even plug holes in corroded surfaces. The rebuilt equipment can then be machined to fine tolerances by normal metal cutting tools.
Depending on the type of machinery to be treated, Polyflake can be applied by spray, brush or trowel method.
Polyflake grade selection
The selection of materials for a given application will depend upon the following factors:
(A) Corrosion environment (C) Mechanical considerations
(B) Operating temperature (D) Application conditions
The base resin selected must be resistant to the environment in which the lining or coating is going to operate. The glass flakes, whilst in themselves chemically resistant, depend upon the resin vehicle for their integrity. It is therefore important to choose the correct resin.
High build system
Polyflake coatings are applied to a typical thickness of 2000/3000 microns (80-120 mils).
In some occasions rebuilding of corroded areas require thicknesses of up to 12,000 microns, which can easily be achieved with Polyflake.
POLYFLAKE – ADVANTAGES
Polyflake can completely restore industrial, marine and chemical equipment to its original condition.
The combination of corrosion and abrasion resistance allows Polyflake to extend the operational life of your equipment.
Delays and uncertain completion dates through conventional repairs, or extended delivery times of new equipment, can be eliminated. Equipment either corroded or worn beyond effective use can quickly be restored to its original condition by Polyflake.
Resistance to undercutting
Resistance to undercutting is crucial because there is always the possibility of mechanical damage to any lining. However, Polyflake’s extraordinary vacuum bonding means corrosion will only occur at the point of damage.
Some alternative linings such as rubber or sheet linings undercut and expose large areas to attack, necessitating costly repairs and more down time.
Polyflake increases the bond strength to the substrate, and has a vacuum effect with the steel which prevents undercutting.
Permeation resistance, next to basic corrosion resistance, is the factor which most affects the life of a lining/coating. Many alternative materials blister and fail prematurely because corrosive agents have permeated through to the substrate. The rate of permeation increases with a rise in temperature and limits the use of many products to 60 to 70°C.
Polyflake systems can and have been used in immersion service to around 100 deg C. Customer evaluation indicates the suitability of one system to withstand double salinity salt water at boiling point. The lining having suffered no degradation after 12.000 hours under test.
Abrasion and Corrosion Resistance
The abrasion and corrosion resistance of Polyflake can increase the life of plant equipment in many areas. For example pumps handling liquids with entrained solids, which previously had to be replaced or repaired every 4 months, have been lined and are still giving good service after more than a year. Other applications include: valves, ship hulls, rudders, propellers; tank floors/walls and stern frames. In all these areas abrasion, corrosion and cavitation were virtually eliminated.
Flexibility is an inherent quality of Polyflake, which will flex up to the deformation point of steel. Though not as good as a soft rubber lining, the ability to operate within the elastic limits of steel is normally sufficient.
Repairability of Polyflake is good (about 99% effective) even after years of service. The damaged area is simply sanded or lightly grit-blasted, wiped with solvent and fresh material applied. With epoxy or rubber linings, repairs are normally about 0% effective.
Rapidity of Cure
Rapid cure at ambient temperatures (10-25°C), Polyflake enables 2 coats to be applied in rapid succession, usually ½ - 1 hour between coats. Full chemical cure is achieved in about 72 hours, but for most environments the coated equipment can go back into service between 4 and 24 hours after treatment. This is important both for initial installation and repairs.
Where new equipment is known to be exposed to harsh operating and environmental conditions, it is considered to be good practice to apply a coating of Polyflake before installation. By doing so, the lifetime of the equipment will be considerably prolonged and downtime for repairs will be reduced.