Zinc plating is a thin film galvanic coating that provides moderate corrosion protection. It is a fairly attractive finish although not highly decorative. It is widely used on hardware (nuts, bolts, washers and screws), construction products (rebar, post brackets, scaffolding supports), electronic components (the frames that hold the wiring) and mechanical parts (packaging equipment, conveyors, lifting devises, etc.).
Zinc plating can be finished with a clear (blue) chromate, a bronze (yellow) chromate or a black chromate. Note: At this time only the clear chromate is trivalent (meets European standards).
Cadmium is another thin film galvanic coating. It is much less widely used because of possible toxicity. Primary uses are in the aircraft industry because Cadmium is much less likely to cause Hydrogen Embrittlement in high strength parts and the marine industry because of Cadmium’s much greater resistance to salt water than Zinc.
Cadmium is also used on some hardware because it will not cause corrosion of aluminum, as zinc sometimes will.
Tin plating is widely used in the electronics industry and to a lesser extent in the food industry. Tin is almost as good a conductor as silver, has greater corrosion and tarnish resistance, and is less expensive. Tin can be quite decorative although it is not generally used for this purpose. One can solder to some forms of tin plating and this makes it particularly useful where many wires have to be attached to a part in an electronics component.
In the food industry cooking pots have been tin coated for years because tin is non toxic and has excellent resistance to corrosion. In the initial processing, the pots are actually dipped into a bath of molten tin, thus producing a thick hard film. Hudson can refinish these pots with tin plating but the electro-deposited film is very thin and therefore will not return pots to original condition.
There are two types of silver plating. One is used to enhance electrical contact and the other is decorative plating for teapots, cutlery, etc.
Silver plating is widely used on contacts and other conductive parts in electrical apparatus such as switchgear and motor control centers because of superior conductivity and longevity compared to copper and brass. The silver is found on the bus, in the circuit breaker, in protective relays, auxiliary relays, control switches, and test switches. The contact points where one piece attaches to another are great sources of resistance, by silver plating these points conductivity is greatly enhanced and corrosion is greatly reduced.
Hudson does this type of silver plating. Hudson does not do decorative silver plating. There are several shops in the Vancouver area that do. Click here for a partial list.
Hard chrome plating is widely used in industry. Hard chrome, as the name suggests, is very hard (Rockwell 64) and very slippery. This makes it ideal for parts that are subjected wear and abrasion. Some common uses are cylinders and cylinder rods, rolls and bars that guide lumber in sawmills, conveyor pins and tracks in automated production lines, and drills and tubes in the mining and oil industry.
What most people think of when they hear chrome plating is not hard chrome, it is decorative chrome. Decorative chrome is for the most part nickel plating for shine and brilliance with a quick flash of chrome to stop the nickel from tarnishing.
Hudson does not do decorative chrome. There are several shops in the Vancouver area that do decorative chrome plating.
Grinding is performed on steel and stainless steel parts where a close tolerance finish is required. Hudson does both surface grinding (for flat parts) and cylindrical grinding (for the outside of round parts).
If you are interested in the grinding facility please click here for some images.
Chromating of aluminum is done mainly for corrosion protection although it does in many cases enhance the appearance. Chromating also provides a very good base for subsequent powder coating or painting.
Chromating can be clear or gold (yellow).