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"Calculating the usage of chemicals per kg plated"

An ongoing discussion beginning back in 2010 ...

February 13, 2010

Q. Hi there,

I have recently joined a company as Works Manager that produces strip and wire formed components as well as some dye casting and the plating thereof.

The company has been around for 40+ years now and I have been given the task of solving the age old costing problem around plating with a focus on Zinc. This is all new to me as I am from Textiles.

Our formula is as follows: Zinc Metal 12-15 g/l, Sodium cyanide 24-30 g/l, and Sodium Hydroxide 70-90 g/l

We plate small items like nails, buckles and coat hanger hooks, etc.

Could someone help me with calculating the usage of chemicals per kg plated? or any other advice to get to an accurate RM usage per Kg?



Stuart Aitken
- Sacks Circle, Bellville South

simultaneous February 13, 2010

A. 1.Analyse the plating bath constituents (Metal,Cyanide & caustic soda) and adjust to your formula mentioned in your letter.Tabulate.
2.Adjust additives to get your standard result.
3.Take production of a calculated quantity say 100 Kgs
4.Analyse and arrive at the qty. of constituents consumed.
5.Note down the qty of additives during this period.
6.Calculate as per cost of the additives
7.Calculate the electricity consumed.
8.From the plating cost of 100 kgs,you can derive at the cost of 1 kg.
Pl.remember about other costs such as labour,rent,office expenses, etc.

t k mohan
T.K. Mohan
plating process supplier - Mumbai, India

February 14, 2010

A. For accurate calculations you need to know the surface being plated and the thickness. According to this all dosing amounts per Ah and therefore re-calculated on the parts. As well an complete analysis of your production must be done to have also an accurate number of labour, tooling costs and energy costs.

Best regards

Dominik Michalek
- Sydney, Australia

February 15, 2010

A. Stuart

I would use an amp-hour meter if you are not already. It is good for surface area plated as opposed to kg processed, such as in a barrel operation. Costs per barrel might be more appropriate in those operations as dragout can be a significant factor in chemical usage. Compare production logs with the additions log.

Willie Alexandeer
- Colorado Springs, Colorado

February 17, 2010

A. It's good to know the surface area, the average thickness plated, and to get a good estimate of the dragout volume per rack and per barrel in order to estimate the chemical use.

the kg can be converted to surface area if the average thickness of the part is known. To estimate dragout, a common method is to start with a still rinse with clean water and carefully measured volume. Then to rinse 10 racks or barrels in it, mix it, and analyze the solution in the tank. From this you can calculate the dragout volume. With this and the thickness being plated, you can estimate your material costs.

It is usually best to do this test on a solution that does not precipitate in the rinse tank, like and acid dip rinse. In this case you can use conductivity instead of a full analysis if you first make a graph of the conductivity of 0.2, 0.5, 1 and 2% solutions of the acid (it should be a straight line if there is no precipitation).

Typical dragout volumes for racked parts are 1.5 to 2 gallons of dragout per 1,000 square feet. For barrels, it varies with size of the barrel, but numbers in the 0.25 to 0.5 gallons per barrel are common for a 24" x 48" barrel.

This may sound complicated, but it should take < 1 hour. Add the metal plated out, and the difference between the cyanide additions and the amount of cyanide calculated by dragout is how much cyanide is lost due to decomposition.

Lyle Kirman
consultant - Cleveland Heights, Ohio

Plating Chemical Usage Estimation

October 19, 2019 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Hello All,
I have been assigned the task to estimate the consumption of chemical utilized in my surface finishing shop.
There is a diverse range of chemical processes in our industry.
How can I estimate chemicals quantity required for the Nickel, Cu & Zn Plating.

syed shah

October 2019

A. Hi Syed. We appended your inquiry to a thread with 4 good answers. You may also find topic 42981 helpful. Please get back to us with your follow-up questions.


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Ted Mooney, P.E. RET
Striving to live Aloha
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