Do you have some questions regarding treatment options or sizes? Perhaps our FAQ section may help.

PROTECTIVE COATINGS

Inorganic Zinc Silicate (Dimet)

Inorganic Zinc Silicate paint is often referred to as “Dimet “ and is a painted treatment using a paint that has a high zinc content applied after sandblasting the steel clean. The paint is applied within a short period after blasting to maximise adhesion and minimise oxidation prior to painting. In our industry a class 2 ½ blast is specified and the paint can be applied in varying thicknesses. The Building Codes of Australia specify a 75 micron thick coat.

Duragal

This is a galvanised coating which is applied when the tube is being manufactured and unlike supagal is only applied to the outer surface of the tube. The coating is thinner and smoother than hot dip galvanising but does not provide the same level of protection.

The coating is 100 grams per square metre in thickness.

This coating provides a nice finish when painted however is not ideal for areas were the steel is in constant contact with moisture such as being built into brick piers.

Supagal

This is a galvanised coating which is applied when the tube is being manufactured and is applied to the inner and outer surfaces of the tube. The coating is thinner and smoother than hot dip galvanising but does not provide the same level of protection.

The coating is 100 grams per square metre in thickness.

This coating provides a nice finish when painted however is not ideal for areas were the steel is in constant contact with moisture such as being built into brick piers.

Hot Dip Galvanised

It is the process of coating steel with molten zinc after first cleaning the steel in an acid bath to remove rust and scale. Zinc is coated over the steel to the following thickness’s of:

Up to 3mm thick material          300 grams per square metre

3mm to 6mm thick material      450 grams per square metre

6mm and over thick material     600 grams per square metre

Duplex Epoxy

The steel is first cleaned in acid and hot dip galvanised to a thickness of 600 grams per square metre. It is then sent to painters who etch prime sandblast the galvanising. This is followed by one coat of epoxy zinc phosphate to a thickness of 75 microns which is then followed by two coats of Micaceous Iron Oxide to a thickness of 100 microns. If a particular colour is required an additional coat is applied in the desired colour. The epoxy coats are far more resistant to corrosion than galvanising and are often specified for buildings in areas close to the ocean and rivers. The coats of epoxy applied over the galvanising are quite soft and chip easily therefore careful handling is required especially is a particular colour is requested.

Powder-coating

Powder coating is a type of coating that is applied as a free flowing dry powder. The main difference between a conventional liquid paint and a powder coating is that the powder does not require a solvent to keep the binder and filler parts in a liquid form. The coating is typically applied electrostatically and is then cured under heat to allow it to flow and form a “skin”.  Its main advantage is it’s hard durable surface tougher than a conventional paint. If used internally it can be applied directly onto metal. For external use it should be applied after a zinc primer. It can be applied over galvanising but white oxidisation will often appear through the powder coating if a zinc primer is not also applied. This is because the rain washes the oxidation away.

A wide variety of colours are available and it is a relatively cheap treatment if additional corrosion protection is not required. It is not suitable is welding is necessary as it is difficult to touch up.