The authoritative public forum
  for Metal Finishing since 1989
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Zipper plating processes: Q&A Problems & Solutions

Q. I AM WORKING IN A ZIPPER MANUFACTURING INDUSTRY. WE ARE DOING DIFFERENT TYPES OF DECORATIVE PLATING LIKE BRONZE, NICKEL, BRASS, ANTIQUE FINISHING AND PAINTING. WE WANT TO KNOW INTERNATIONAL STANDARDS AND TEST METHODS FOR DECORATIVE PLATING AND PAINTING. PLEASE ADVISE A SUITABLE BOOK.
THANKING YOU

UMAPATHY
ZIPPER MANUFACTURING - CHENNAI
2005

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Process sequence for tin or brass on zinc zippers

Q. We are zipper manufacturer. We want to plate Tin & Brass on our zinc die cast zipper samples. what are the process sequence we will follow to get good results.

SATHISH . G
Textiles Exporter - India
2007

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Using nickel-plated hardware on items to be laundered

Q. I'm starting a bag business and am confused about appropriate hardware to use on the bag straps. I've found "nickel-plated metal rings and slides." These bags will be laundered, so I'm worried the nickel-plated hardware will rust from being washed in water. Stainless steel hardware is significantly more expensive.

Someone told me to try putting a strong magnet up to the nickel-plated hardware: If the hardware is strongly magnetic, it will probably rust. If it's not strongly magnetic, the hardware should be OK through washings. Is this true?

One of the samples I got was not magnetic. The other two samples were VERY magnetic.

Please help! I don't want my products to end up with rusty hardware.

Thanks so much.

Susan Chuang
bag designer - Los Angeles, California, USA
January 29, 2008

Thank you so much, Gene & Mark! Unfortunately, the sales reps that I've been in contact with don't know what type of plating was used on their hardware. They just know it's "nickel-plate." Haven't come across any lacquered nickel plate options so far, but I'll try to find out more about launderability specs.

So, Mark ... you think the non-magnetic nickel plate slide would be safe to launder? The rings, unfortunately, are super-duper magnetic.

I may just have to bite the bullet and buy the stainless steel hardware to be safe. ** sigh **

Susan Chuang [returning]
- Los Angeles, California, USA

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Black nickel look for brass zippers

Q. Hello!
We are a brass zipper manufacturing company and we want to know the cold water chemical process that will help us to give our brass zipper the shining black or black nickel color.

Ashish Jain
buyer - Ludhiana, Punjab, India
May 22, 2008

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Zinc Die Cast Zippers: Improving washing performance

Q. We manufacture zippers with zinc die cast components. After painting with epoxy, when the zippers are attached to the clothes like skirts, cushion covers, etc.. they are subjected to domestic laundry washing process, paint is chipping off happens and runability of pullers also suffers. Can anyone suggest a better way or improve the resistance of epoxy paints on zinc die cast components

KP Unni
Product designer - Chennai India
February 1, 2010

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Identify this finish from the picture

Q. I am sending you image of part and please suggest what types of plating or coating is there on material. Either it is having satin nickel, with electrophoretic lacquer or it is having PU Coating, or is it pearl chrome plating; base material of part is zamak.

Please suggest.

ASHOK THETE
plating shop employee - NASHIK, MAHARASHTRA, India
August 17, 2017

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Need harder nickel-free plating for zipper sliders

Q. Hi All,
Love the forum and all your work!
I make leather accessories, and source hardware from China and Italy and Japan.
This enquiry relates to our zipper sliders which are the little carriage that combines and separates the zipper teeth.
They are die cast from zinc, and then electroplated to our desired colours.
Those colours being rose gold (I assume bright acid copper) with a lacquer, a gold colour (Not a straight brass, but I'm not sure of what colour) and a silver colour that is called nickel-free.
Over the last couple of years with our current supplier, we have found zippers that are opening behind the slider as the zipper is pulled closed.
The obvious culprit would be teeth wear, but this is not the case. While the teeth do wear over time, it is always the slider that has worn on the internal surfaces and is no longer combining the teeth correctly. (*On a 10+ year old zipper it might be the teeth, but the slider would have likely gone first)
We are seeing this in as little as 6 months in high use items with 20 odd openings/closings per day.
We make our items to last, and ideally want a minimum life of 3-5 years, so a slider failure after 6 months is a disaster from a reputation standpoint.
(We don't claim 3-5 years and only offer a 12 month warranty, but we fix anyone's bags for free for life basically [within reason]).
So when anyone presents with this fault, we replace the slider and problem is (temporarily) fixed.
Problem is, We sell to tourists and many of those will not be able to come back, and if they have the problem, they may just assume our product is not good and write us off.
Our old supplier's slider did not have this problem, and I still occasionally see them at 10 years old and going strong.
I have asked our current supplier about why, and they have no idea ... initially I thought changing sliders would solve the problem. As it must have been something about the internal geometry that was different, and causing the problem, but in the middle of the night I was lying there thinking about it, and it occurred to me, that the thin plating they put on the current sliders has very little abrasive resistance, and the same would likely be true of the inside.
In basic tests I have tried previously, the current pullers (the tab attached to the slider) which are plated while attached to the slider, in as little as 6 short pulls across a green scotch brite pad, it would already be worn through the silver colour, to the copper underneath, and quickly through that and to the zinc... the old puller could go more than 40 pulls of the same nature and not get through the silver.
So ... cutting an extremely long story short, I think this lack of thickness, and possibly hardness, is the reason for the premature failure of the sliders.
Now to my question!
I want to get my supplier to get some sort of harder and thicker plating down on the initial raw/polished slider, before it is sent to the decorative plater.
I should have mentioned before that they are rack plated, not barrel.
So my question is, what sort of hard coating would be ideal? Nickel? And if yes, what thickness would provide some good wear resistance, and still be achievable for these kind of low cost items?
I know there are lots of ways to get a hard finish, but I need a simple affordable solution. I don't have contacts over there who can manage this issue unfortunately, and my contact would be one of the the only ones who can speak english in the company. He also knows nothing about electroplating.
Getting them plated here is not an option unfortunately either.
To give you an idea, the slider and puller combined are a USD$.05 item, and the highly polished rack plating with lacquer takes that cost to about USD $0.30 in total, plus the zipper and assembly etc. I understand that this extra process will cost more, and happy to pay to improve our product, but it definitely can't increase the cost by $1, as our margins would not allow that.
I think the hard base plate would solve our issues, and be achievable for those platers, or another plater in the region, but I lack the technical knowledge to ask for what I need or source another supplier, so any advice anyone can offer would be greatly appreciated.
Thanks in advance,
Ben :)
Btw, old supplier's zippers were not up to scratch and they would not give me the details of just their electroplater.

Ben Thompson
Owner/ maker /product source - Sydney, NSW Australia
January 28, 2020

Q. Hi Ted,

Thanks so much for replying.

I was possibly not clear about the "Nickel free" finish. The Term nickel free is used by a few suppliers I have dealt with as the name for the silver colour.

I am aware it is not a colour, and is just a term for nickel free plating, but that's not how they use it, and for brevity, I probably glossed over that bit.

I do not require these items to be nickel free, as they are not in direct contact with the skin (and we don't sell anywhere in Europe), so I thought that the actual nickel plating would likely be harder than whatever silverish alloy they call "nickel free", and probably a simple solution, as finding a plater to plate nickel might be easier than the r & d of trying to get a chrome base to work.

My understanding of why we rack plate is that we require a highly polished finish on a small item with tight angles, and barrel plating will not give the desired results as polishing stones can not get in to all the little crevices etc.

Changing to another zipper supplier is unfortunately not an option, as it took me 10 years to find the current supplier, and I have not been able to find any others who can match their quality in terms of teeth, and finishing.

An Indian plater would be an option, but that would require shipping the sliders to India, and hopefully getting the desired result, then shipping them back to China for finishing and assembly.

I feel a much simpler option would be to get the existing plater to do the existing plating thicker or to put a thicker layer of actual nickel. Or to get them to find another plater nearby who can do what we need, so I want to be armed with the specific of what I need before asking again to improve the plating.

I should have mentioned previously, that we are talking about 5000-10,000 units per annum of a small component of a small (but important) part of our bags, and therefore this is not something that I could justify flying to china to take care of.

Also, I have previously asked them to increase the plating thickness, and they have said the only option is to run the parts through the whole process twice, as our plating run is way too small to be done on its own... It's put in with tens of thousands of others.

So, to cut an extremely long story short again, my question is; Is nickel plate likely much harder than most silver colour "nickel free" finishes used in decorative plating of small inexpensive items? (excluding Chrome of course).

And what sort of thickness should I be requesting? Would 5 or 50 microns of nickel be suitable, and would it be a reasonable request? And if Nickel is not harder than the alloy currently used, what thickness of that should I ask for.

I will definitely take your advice re the barrel plating, and see if that's an option for the slider itself, and maybe they can get the desired smooth finish.

... and I just read the title of my post and I know see why it looks like a wanted a nickel free plating option... face palm emoji.

Thanks again for your advice Ted,

Ben :)

Ben Thompson [returning]
- Sydney, NSW, Australia