Size Considerations for Structural Fabrications to be Galvanized
Throughout North America, a variety of sizes of hot-dip galvanizing kettles is available, allowing a wide size-range of structural fabrications to be galvanized. Designing and fabricating in modules suitable for the available galvanizing facilities allows almost any component to be galvanized. For oversized fabrications, best practice suggests that they be designed in modules or sub-units and assembled after galvanizing.
Threaded items and smaller items such as fasteners, small brackets, nuts, bolts and clips, receive special attention during galvanizing. Small pieces are frequently galvanized in perforated baskets, which are centrifuged or spun after galvanizing to remove excess zinc, delivering smooth coatings.
It is wise to consult with your galvanizer regarding kettle capabilities at an early stage in the design.
- When an item is too large for total immersion in the kettle of molten zinc but more than half of the item will fit into the kettle, it may be progressively dipped, sometimes referred to as “double-dipped.”
- When the need for progressive dipping is anticipated, adequate venting must be provided at both ends of the structure.
- When an article of small mass or asymmetric design is progressive-dipped, there may be a change of shape and/or movement from the centerline of the article. (See Bracing Pieces for Control of Warping & Distortion During Galvanizing.)
- It is best to consult with your galvanizer before planning to progressive-dip.
