Zinc Mechanical Galvanizing

Zinc mechanical galvanizing is a barrel process conducted by “cold welding’ (impacting) a powder form of zinc into the surface of steel parts using media (glass beads). The kinetic energy created by the rotation of our barrels, part-on-part contact and media-on-part contact creates a more porous zinc deposit than typical electroplating. This porosity allows hydrogen to relieve naturally within 24-48 hours, meaning there is no need for hydrogen embrittlement relief. With the capability of creating zinc deposits as thick as 0.003”, mechanical galvanizing offers superior corrosion resistance than mere electroplating.

Plateco offers a number of mechanical plating specifications, including ASTM B695 and John Deere (JDM F22) and more.

The Art

Here at Plateco, we were founded on zinc mechanical galvanizing, starting with a barrel cement mixer in our founders’ garage in 1973. Nine years later in 1982, our humble roots evolved into a 10,000 square foot facility with three state-of-the-art mechanical galvanizing barrels that are around 10 times the size of our old cement mixer. Talk about an upgrade!

We understand that this process is not something that can be computer automated. Zinc mechanical galvanizing is an art form. It takes finesse and in-depth planning, which is why our artisans – production operators – are highly experienced and meticulous, expertly controlling the concentration, temperature, time exposure of plating chemicals, speed and angle of our barrels, and many other variables to ensure that your product is plated to your exact specifications. It is a responsibility our artisans yield with truly amazing results.

An Alternative to Hot Dip Galvanizing

Hot dip galvanizing is conducted by immersing product into a bath of molten zinc, an extremely dangerous process, whereas mechanical galvanizing uses kinetic energy and glass media to impact a powder form of zinc onto the surface of product. It’s generally accepted that this process often provides at least as much zinc protection as hot dip galvanizing, while being superior in many ways. Numerous tests conducted in accordance with ASTM B117 show that parts mechanically galvanized to a thickness of one ounce per square foot typically last at least 300 hours in a salt spray chamber, while parts that have been galvanized using hot dip often do not.

Of equal concern is the fact that parts that have been hot dip galvanized will sometimes exhibit severely premature red rust. This could be attributed to “interlayer corrosion” – the corrosion of the iron-zinc layer between the substrate and the galvanized coating. In addition, hot dip galvanizing can exhibit a great deal of thickness variability, which results in some parts lasting a long time while other parts fail prematurely. Neither of these problems exist with mechanical galvanizing.

Other advantages of mechanical galvanizing over hot dip galvanizing include:

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No need for hydrogen embrittlement relief

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No risk of de-tempering

The heat from hot dip galvanizing can negate the tempering process that increases the hardness and toughness of the metal when the part is manufactured.

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Better thread fit between fasteners and chasing nuts

Mechanical galvanizing does not fill the “valleys” of threaded fasteners, which allows fasteners and nuts to mate easily and quickly. This is not the case with hot dip galvanizing.

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No galling

Because of the naturally lubricious nature of zinc mechanical galvanized coatings, there will be no galling (no wear caused by adhesion between sliding surfaces). This will produce more accurate torque-tension relationships than with hot dip galvanizing.

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No stickers

In hot-dip galvanizing, molten zinc often fuses parts together, resulting in lost time, effort and materials as well as the need for extra assemblies. This is not a problem with mechanical galvanizing.

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Better adhesion

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