ZINGA vs HDG
Active cathodic protection
ZINGA® has the most important advantage that it offers a real cathodic (galvanic) protection. ZINGA® has a concentration of 96% special zinc in its dry layer which gives it its galvanic characteristics. The film galvanising system ZINGA® (also called “Zinganisation®“) shows comparable protection to HDG and in some circumstances even superiour protection (e.g. in immersion).
Steel members which have been hot dip galvanized have proven cathodic protection by the sacrification of the Zinc on the surface. Damages to the steel substrate show protection by the throwing power of the zinc layer. The Zinc layer diminishes because of the depletion of the Zinc.
For more information see “How does it work?”
Easy application on site
ZINGA® can be applied in the same way as paints.
Hot dip galvanization cannot be applied on site, the structure has to be dismantled; transported to the hot dip planted; hot dipped, transported back to site and reassembled.
For more information see “Application”
A cured ZINGA® layer, will reliquidise if a new layer of ZINGA® is applied. This ensures the creation of 1 ZINGA®layer with a continuous electrochemical contact between the Zinc particles and thus galvanic protection. If the ZINGA®layer is very old, the Zinc salts on the surface (ensuring a passive protection), need to be removed to ensure complete reliquidisation; this can be obtained by performing a light sweep blast.
Hot dipped structures cannot be hot dipped again unless they are dismantled, blasted and dipped into the Zinc bath. ZINGA®‘s mechanism of protection is so similar to conventional galvanising that they work in complete unison, as they are merely different forms of zinc. Rather than replacing galvanised assets, structures can simply have their protection “re-charged” by applying ZINGA® to the rough surface of the old galvanising after appropriate deconta-mination and removal of the salts.
ZINGA® can be overcoated with a fast drying, compatible paint. Care should be taken to avoid affection of the Zinc layer by aggressive solvents of the topcoat.
Not only does HDG requires specialized, compatible paints; a thorough surface preparation is also needed before the application of a topcoat on HDG. This includes alkaline or acid rinsing and sweep blasting the surface.
For more information see “Overcoating of ZINGA”
Application under extreme circumstances
ZINGA® can be applied in a wide variety of weather conditions. The application surface temperature range is from -15°C to +40°C with a maximum humidity of 95% so long as the dew point is 3°C above the steel temperature.
Not applicable. A HDG layer is applied in the hot dip plant.
Unlimited shelf life
ZINGA® has unlimited shelf life. This means it is possible to always have ZINGA® in storage for touch up or for future projects.
Contact with potable water
ZINGA® only contains non-toxic elements in its dry layer (after evaporation of the solvent). Therefore it can be, and has been, used in contact with potable water. Since the ZINGA® remains active, it produces Zinc salts which dissolve in the water. This can sometimes lead to small precipitations in the water, which are however non toxic. To avoid this, we recommend to wash the surface very thoroughly with fresh water. For more information, contact a Zingametall representative.
The American Water Works Association (AWWA) allows the use of galvanized steel for water storage tanks. Only galvanizers that have submitted test coupons of their galvanized steel and have been approved by the NSF have the authority to galvanize steel for use with potable water.
ZINGA®, containing 96% Zinc in the dry layer has very few binder. In fact, not every Zinc particle is completely surrounded by resin. This also explains why the ZINGA®layer is rough and porous. However, this is why ZINGA®behaves like a metal when it comes to impact and bending. ZINGA® can be bent over very small angles without showing cracks in the dry layer.
When hot-dipped structures are bent over a certain angle, the coating will be affected and the total structure will need to be hot-dipped again to restore the coating. It is also recommended to restore these coatings by using a zinc rich liquid coating (like ZINGA®).
In general, it is advised to bend the structures before hot-dipping. In practice, this is not always possible (e.g. pipes that need to be fitted to form connections).
Welding on coated steel
Zinganised® steel can be welded without the release of any toxic fumes (tested according BS 6853) and with a very small burn back. Since the ZINGA® is not in any way alloyed with the steel, there is no danger of zinc inclusion in the weld.
Welds are advised on steel free of zinc to prevent strength reduction through zinc inclusion in the weld itself (since the Zinc is molten into the steel – alloy). The zinc coating should be removed at least one to four inches from either side of the intended weld zone and on both sides of the steel part. Grinding is the most effective means of removing the galvanized coating.
Structure keeps its form during application
ZINGA® is applied under ambient temperature and does not deform the structure.
With hot-dip galvanisation, deformation of the structure is possible due to the use of high temperatures of molten Zinc. There is also potential for hydrogen embrittlement within welds. This can lead to problems when structures are precisely measured in a steel structure to form connections.