Frequently Asked Questions on Electroplating
Q. Why has my bumper got black pits all over it?
A. If it is the back bumper, usually the corrosive carbon monoxide from your exhaust, and a combination of the porous nature of the chrome and pores in the base steel produces thousands of these small eruptions (rust pits).
Q. The door handles on my old car have blistered, and white powder has formed underneath.
What is it?
A. Your door handles are made of die-cast alloy, commonly refered to as "muck metal", which is actually a zinc alloy. This chome silver gold copper plating polishingalloy was used to manufacture these compounds as a cost effective, easy to cast material. However, the draw back is that die cast zinc is a very active metal, it is used as a sacrificial metal on boats, older car parts etc, and reacts with salt, oxygen, water and a whole lot of other things.
Due to the porous nature of chrome, and usually a lack of maintenance (ie. left dirty, wet and un-waxed), the base zinc starts to corrode and the chemical reaction releases hydrogen gas which in turn forms "blisters" on the surface. Eventually the blisters pop and you see the white zinc oxide below. This gassing will still happen after new electroplating, due to a chemical reaction during the plating process. This is because it is impossible to remove all existing oxidation from the original zinc die-cast.
Q. How can I fix the die cast when it has badly blistered?
A. Sometimes we can grind the blisters out, but if they are too deep we have to use the "drill and fill" method, eg. drill out each hole and individually fill with Alusol. This can be a very expensive process, sometimes $10-$15 per hole, and as you can imagine there can be between 30-100 holes in each item.
Q. Is there a more economical way to fix badly blistered die cast?
A. Yes. The easiest way for all concerned is to send the item to a metalwork forge and get a new item cast out of bronze or brass. Then bring the newly cast item in, and we will linish and polish to a high finish and triple plate it to look brand new. This will be more economical and also last significantly longer than a repair to the original item. Just be aware that some machining and tapping of thread may be required (before bringing in for plating).
Q. Do you do tin plating?
A. Yes we do, we use pure tin and it is food grade and the best you can get.
Q. What items would you tin plate?
A. Meat mincing machines, cream separators, cream cans, inside of chef's pots, or any other item likely to be used with food, where the highest standards of hygiene is required.
Q. What about tin plating instead of electo-galvanising?
A. This is very common, but more expensive than galvanizing. The advantages are that it is not a sacrificial metal (the tin plate is not designed to deteriorate like the zinc in galvanizing). Tin plating is ideal for hinges, nuts and bolts (where a softer finish is desired). However tin plating is not recommended for high temperature applications (such as exhaust pipes etc).
Q. What are the easiest metals to chrome plate?
A. Brass and copper.
Q. Is it possible to chrome plate plastic?
A. Yes, but only if the plastic has been pre-treated with a very thick metallic base coating prior to electroplating. We are not aware of anybody in New Zealand who is currently able to do this. Electricity is used to deposit the chrome and the base has to be electrically conductive to achieve this. Smaller plastic parts are more difficult to chrome plate.
Q. Can you electroplate aluminium?
A. Yes. There are a few more processes involved than when electroplating steel, but great results can be achieved.
Q. Can you re-plate chrome to steel wheels?
A. Yes. However, due to new safety regulations the wheel has to be disassembled (center and rim separated), chrome plated in two parts then re-assembled and certified - otherwise it will not be covered by insurance.
Q. Can you chrome plate alloy mag wheels?
A. Yes, but a mounting jig has to be made to suit each style mag. These jigs have to be made from titanium and cost approximately $2200. Because of the number of different styles of mags available I would have to have a jig for each style and in order to make them viable I would have to pass this cost on to the customer - (would you like to pay over $3000 to plate four mags, after having already spent money buying the wheels?!).
Dont be fooled by some "chrome" mags that are out there. They are just painted with a very shiny and reflective paint. Real chrome mags are only viable straight from the factory as they would chrome them by the thousands and spread the jig cost over these large numbers.
Q. Why does chrome plating sound expensive?
A. Chrome plating involves a 40 stage process, whether it is a dressmaking pin or a Kenworth truck bumper. It is not just a simple process of dipping something into a tank and then taking it out. A lot of time and labour is involved as well as chemical costs. The chrome tank cost $17000 - that's just one tank, and 7 different tanks are used during the process.