Hot Dip Galvanizing
for Wrought Iron Railings
The galvanizing process has been used to protect metal from
corrosion for hundreds of years. The process basically involves cleaning the
metal then dipping it into a vat of molten zinc. The multiple layers of zinc
that form from this process prevent the underlying steel from corrosion even in
salt laden ocean front environments. The zinc does more than just coat the
metal, it metallurgically bonds to it, actually becoming part of it. These
layers dissolve at a very slow rate (acting as a sacrificial layer) and without
creating rust thereby providing decades of protection to the underlying iron
work.
The level of
protection is determined by:
1.
Coating thickness. The thicker the coating the
longer the life.
2.
The intended environment (geographical location)
where the ironwork will reside. Enclosed pool areas, ocean front properties or close
proximity to salted roadways all require a thicker coating of zinc. It's important
to understand service environment when specifying a galvanized coating
thickness.
Advantages of
Galvanizing:
- Relatively low cost compared to using nonferrous
(non rusting) metals like stainless steel or aluminum.
- Low maintenance, coatings can last 25-50+ years.
- Durable, scratch resistant.
- Scratches or abrasions that compromise the
coating are still protected by the surrounding zinc (galvanic cell).
- Since during the hot dip process, the iron work
is completely immersed in the molten zinc, the insides of tubing and interior crevasses
of scroll ironwork get fully protected.
- Can be painted or powder coated over the galvanized
coating to enhance the beauty and add even more corrosion protection.
Disadvantages of
Galvanizing:
- It is difficult to control drips and sags and
other surface imperfections so the resulting surface is not as fine (even after
powder coating) as it would be if powder coated alone.
- Galvanize dip tanks are limited in size which sometimes requires breaking up large sections of railing into smaller sections in order to fit them into the tank.