FAQ’s

The galvanizing process removes light mill scale, water-based markers, light oils and small amounts of grease.

Our processes are unable to remove welding slag, burrs, oil-based paint/markers, wax, epoxy, heavy grease, lacquer, varnish or casting impurities.

Zinc metal used in the galvanizing process provides an impervious barrier between the steel substrate and corrosive elements in the atmosphere. It does not allow moisture and corrosive chlorides and sulfides to attack the steel.  Zinc is more importantly anodic to steel, meaning it will corrode before the steel, until the zinc is entirely consumed.

The three inter-metallic layers that form during the galvanizing process are harder than the substrate steel and have excellent abrasion resistance.

Zinc on newly galvanized steel is very reactive and wants to form zinc oxide and zinc hydroxide corrosion products that eventually become the stable zinc carbonate. When galvanized steel is tightly stacked or stored in wet boxes that don’t allow for free flowing air, the zinc forms excessive layers of zinc hydroxide, otherwise known as wet storage stain. Most wet storage stain can be easily removed with a cleaner or nylon brush. To prevent wet storage stain, store galvanized steel indoors or block it so that there is ample free flowing air between each galvanized article.

The steel chemistry is the primary determinant of galvanized coating thickness and appearance. Continuously cast steel produced by the steel companies has a wide variety of chemistries, thus the different coating appearances. There are several different additives that galvanizers may put in their zinc kettle to enhance the coating appearance by making it shiny, spangled or matte gray. The appearance of the coating (matte gray, shiny, spangled) does nothing to change the corrosion protection of the zinc coating.

Called duplex coatings, zinc and paint in combination (synergistic effect) produce a corrosion protection approximately 2X the sum of the corrosion protection that each alone would provide. Additionally, duplex coatings make for easy repainting, excellent safety marking systems, and good color-coding. Painting over galvanized steel that has been in service for many years also extends the life of the zinc coating.

Depending on the product mix, square feet per ton, and condition of the steel surface, galvanizing is often less expensive on an initial cost basis. However, as with any purchase, the lifetime costs should be considered when making a project decision on the corrosion prevention system to utilize. And, with galvanizing, the life cycle cost, i.e. the cost per year to maintain, is almost always less than a paint system. Paint systems require maintenance, partial repainting and full repainting several times over a 30-year project life. The costs can be staggering, making the decision to paint a costly one in the long run.

Galvanizers can progressively dip such a fabrication or article of steel. They dip one half in the molten zinc bath, remove it, turn it around or over and immerse the other half in the zinc. We refer to this method as ‘double dipping’.

Coating thickness depends on the thickness, roughness, chemistry, and design of the steel being galvanized. Any or all of these factors could produce galvanized coatings of non-uniform thickness. Members of the American Galvanizers Association galvanize to ASTM standards, which define minimum average coating thickness grades for various material categories.

Minimizing potential warpage and distortion is easily done in the project’s design stages by selecting steel of equal thicknesses for use in every separate sub-assembly that is to be hot-dip galvanized, using symmetrical designs whenever possible, and by avoiding the use of light-guage steel (<1/16″ / 1.6 mm). Some structures may benefit from the use of temporary bracing to help maintain their shape and/or alignment.

Galvanized coatings can be easily and effectively painted, not only for aesthetics but also to extend the structure’s service life. The age and extent of weathering of the galvanized coating dictate the extent of surface preparation required to produce a quality paint system over galvanized steel. ASTM D 6386, Practice for Preparation of Zinc (Hot-Dip Galvanized) Coated Iron and Steel Product and Hardware Surfaces for Painting, should be consulted for suggested surface preparation methods for galvanized coatings of varying ages.

‘Double-dipping’ is the progressive dipping of steel that is too large to fit into the kettle in a single dip. Double dipping does not produce a thicker hot-dip galvanized coating. For example, if the piece of steel to be galvanized is longer than what will fit in our kettle in a single dip, we’ll first dip one end, turn the piece of steel, then dip the other end.

The primary reason for vent holes is to allow otherwise trapped air and gases to escape; the primary reason for drain holes is to allow cleaning solutions and molten zinc metal to flow entirely into, over, and throughout the part, and then back into the tank or kettle. Inadequate venting and drainage will cause problems with the quality of the finished product and the worst case scenario is that the product may rupture or explode due to the increased air pressure from dipping the steel into molten zinc. 

Silver City Galvanizing has two separate galvanizing kettles. The large kettle is 31’x 5’4″ wide and 6′ deep. The second kettle is used for smaller material and is 8′ x 3’6″ wide and 5′ deep.

Yes, if you do not have an account set up with Silver City Galvanizing. We accept credit card payment for invoices with a value less than $2000. We also accept payments in the form of cash, cheque or electronic funds transfer (EFT). Please contact us to make payment arrangements.

Yes, over the years, we have temporarily closed the plant for upgrades or repairs to our process lines and to perform preventative maintenance. We undertook a significant upgrade to our pickling line, resulting in a plant shutdown from Nov. 25 to Dec 23rd, 2013. In the fall of 2017, our small kettle line was out of production while we installed a new one.