Steel Tube Powder Coating
Powder-coating Allied´s galvanized steel tubing provides at least 5 to 6 times greater corrosion resistance than powder coating over uncoated steel.
The Flo-Coat® Process
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- 140°F.
- Two-stage rinsing is preferred, with the final rinse being fresh water.
- Dry-off should not exceed 450°F 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:
- ZRC cold galvanizing compound (battleship gray)
- ZRC Galvilite cold galvanizing compound (shiny)
- Rustolastic #24-A-120 (sales code 073258)
These paints are available directly from the manufacturer.
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:
- High bake thermoset acrylic, 350°F at 15 minutes.
- High bake alkyd, 350°F at 15 minutes.
- High bake polymer, 350°F at 15 minutes.
Others may require individual evaluation.
* Tests independently conducted by Scientific Control Laboratories, Chicago, IL in accordance with ASTM B-117 and ASTM D-1654. Detailed Scientific Laboratories´ test results are readily available from your local Allied Sales Representative.
Contact one of our Sonco Tube professionals who are standing by to provide additional information or to provide a free quotation for your next project.