Chrome Plating is not as simple as 'just dipping it' in the solution. It is actually very complex, as you can see from the picture. Learning how to do this properly takes years. However, it is very interesting, and the journey from Apprentice to Platers Helper to HCP status is quite rewarding.
The process of electrolysis accomplishes chromium plating. Utilizing DC current at a specified voltage and amperage, you have a Cathode, which is negative (the part to be plated) and an Anode, which is Positive. The Cathode is placed at a predetermined distance from the anode in the electrolyte (the solution), and the current is applied. The amount of time the Cathode (part) is left in this condition will determine the thickness.
Various different types of masking are utilized to stop off on areas that do not require plating—tapes, plugs, shields, special lacquers, etc. A good plater knows what to use, so just tell them what you do not want to be plated. Or just tell them what is to be plated. They will figure out the rest. If not, they will contact you for clarification.
So now, lets Chrome Plate something: After a part arrives in the plating plant, it goes through Incoming Inspection. Verifying count, condition of material, and figuring out where and how much plating is to be applied are some of the areas covered.
Once this is determined, it will be masked off for abrasive blasting to ensure the area to be plated is very, very clean. After blasting, the area is kept protected so as not to form any oxides on the surface. It must not be touched by anything from this point onward.
The part is then masked and racked for plating. Very expensive tapes (some costing as much as $50 a roll at this writing), lacquers, shields, plugs, etc. are used. Knowing what and where to apply takes years of knowledge to master.
After masking, an electrode (anode - Positive in the tank, remember?) has to found or fabricated to conform to the configuration of what you are plating. This is also a crucial step in the process and requires years of knowledge to fabricate properly.
The part must now be 'racked' for introduction into the plating bath. Again, this takes years to learn properly in order to obtain the desired results, first time and every time. Make sure your plater has significant experience in the business. The best Hard Chrome operations do not get involved in other types of plating. Hard Chrome is complicated and takes all of your resources to do a good job, consistently.
The efficient accomplishment of all these tasks is imperative in order to make a profit in Hard Chrome processing.
We are now ready to place the part in the plating solution. In-Process Inspection is required at this time. The Plating Bath 'make up' (ingredients) are verified, as well as temperature, voltage, amperage, and anode to cathode spacing. All electrical contacts are cleaned to ensure proper transfer of current. Properly executing how all these things are adjusted also takes years to learn.
The part is now 'reverse current' etched for final cleaning and activation of the surface. This ensures proper adhesion in that you not only have a mechanical bond but a molecular bond as well. Knowing how long and at what current valuations is critical.
After proper 'reverse' the part is placed in plating position, and the actual plating commences. The proper voltage and amperage is adjusted on the DC power supply.
The plating 'rate' is now determined, and the part is allowed to remain in the solution for the proper duration to obtain the required 'build-up' of Chromium. Plating rates are very slow for Hard Chrome plating, generally, in the neighborhood of .001" per hour. Faster rates are possible with our proprietary process. The Jersey Chrome hard chrome process is superior in not only plating rate but hardness and other properties of the deposit as well. Maybe you have tried the rest...now try the best.
Now you have some idea as to why it sometimes takes so long for you to get your parts back from your other plater.
The part must be attended to during the plating process. 'Trees', solution level, and monitoring of all values previously mentioned are very important. One small detail left unattended, and you will have to strip the part and start all over again. This is one reason it is difficult for your plater to give you a delivery date...things go wrong, and the delivery date has to be pushed back due to reprocessing. Use a plater that has the proper experience and you will eliminate delays and missed deliveries. Jersey Chrome's on time delivery is 99.9%.
After plating, the part must be inspected, unracked, masking removed, and then rinsed and cleaned. This also can take considerable time, as the 'masks' are very durable, being able to withstand an acid solution at high temperature. They sometimes must endure plating cycles of 48 hours or more for heavy build-ups.
After cleaning, Final Inspection is made to verify plating thickness, visual on the chrome and part condition, proper cleaning, etc.