Galvanized structures often need to be coated.  New structures may be going into service where the zinc layer will not form the familiar patina and thus will self-sacrifice prematurely.  On old structures, the zinc may be damaged or simply depleted.  Historically, the only recognized and permanent form of surface preparation has been grit blasting, a process that removes part of the zinc and often fractures what is left.  It’s expensive and, because of multiple variables, often gives inconsistent results.  Less invasive approaches such as chemical pretreatments have been tried many times but only work in mild environments.  Long term, nothing other than blasting works on hot dip galvanized steel: - that is, until the invention of GalvaClad^®.

With its GalvaClad^® series, Madison Chemical offers a complete line of high performance coatings specifically formulated for protecting galvanized structures without the need for elaborate surface preparation such as blasting.   A simple one-step acid etching process, followed by GalvaClad^® protective coating, provides performance comparable to a white metal blast without removing or fracturing the zinc.  These products are suitable for immersion and embedded service as well as atmospheric exposure. 

If you prefer to blast, GalvaClad^® is still the product of choice.  All other things being equal, it will increase adhesion by 50% or more, especially where the blasting equipment, media and other factors are not optimal and the results might otherwise be marginal.  It is also of interest where the customer is already getting good results  but wants to drive down the cost and severity of the blast. 

Think, then, of GalvaClad^® in two ways, as a way of cutting back on the blast and as a way of eliminating it altogether (i.e., by using non-invasive acid etch instead)

The GalvaClad^® product line includes a plural component high build, quick set, aromatic corrosion coating, a similar format of aliphatic (colour stable) coating and a Mix-and-Apply paint-like liquid zinc product.  The 2 plural component systems are typically applied in one multi-pass coat to virtually any desired thickness.  GalvaClad^® Liquid Zinc can be used on its own or top-coated with a Mix-and-Apply finish coating such as Madison AcrylaThane^®, or a precatalyzed coating such as TufSheen^® PreCatalyzed.  

To find out more about the history and development of GalvaClad^® and an overview of the products, click here to view our press release dated January 2008 announcing this technology.

For additional information regarding technical aspects and laboratory test results, click here for our latest InfoTech Bulletin.