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Powder-coating Allied's galvanized steel tubing provides at least 5 to 6 times greater corrosion resistance than powder coating over uncoated steel

Allied's unique Flo-Coat process is the superior method of galvanizing steel tubing. It begins with flat strip steel, which is then cold-formed and electric-resistance or induction welded. After welding, the tube receives a triple layer of protection-zinc, conversion coating, and a clear polymer top-coat - all applied in- line to assure a uniform coating. The result is a smooth, shiny end product appearance that is unmatched in terms of strength and durability.
Flo-Coat tubing exhibits greater corrosion resistance because of the synergism created between the coatings; the conversion coating passivates the zinc to slow down the white rust growth process, and the clear top-coat then "seals in" the protection. The clear third coating also acts as a primer for powder- coating. Extensive pre-cleaning is unnecessary, and excellent adhesion and abrasion characteristics are achieved, even at high baking temperatures.

Surface contaminants deposited on Flo-Coat tubing during storage, transit, handling and processing must be removed prior to powder coating. Allied recommends the following cleaning process for Flo-Coat:

Tubing should be cleaned with a mild alkaline solution at 1 to 2 oz. Per gallon concentration, at 130- 140øF.
Two-stage rinsing is preferred, with the final rinse being fresh water.
Dry-off should not exceed 450øF peak metal temperature.

Solvent degreasers and conversion coatings will damage Flo-Coat product. Mild phosphate or acid-based cleaners are not recommended but typically produce an acceptable result, although prolonged exposure to acid-based cleaners may damage the interior coatings.

When Flo-Coat tubing is going to be welded before powder coating and there is a concern about corrosion protection in the weld area, Allied suggests four cold galvanizing compounds that are heat resistant (up to 750°F) and act as a primer for powder coatings:

These paints are available directly from the manufacturer.
Another method of restoring corrosion resistance is thermal spray. Thermal spraying is a process by which zinc wire is continuously melted and projected by compressed air onto a prepared surface. For more information, please contact your sales representative.

Allied's Flo-Coat tube is protected by a clear polymer topcoat which provides excellent adhesion properties to most thermoset powder coatings: