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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing 1989-2024
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Zinc plating is low quality -- what's the alternative?
Quickstart:
Many applications require a metallic finish rather than paint or powder. Zinc plating is the least expensive such finish, so there is sometimes competition between plating shops to sell at lowest cost by offering a very low quality commodity with emphasis on high volume, and little if any QC/QA. Zinc plating is NOT inherently low quality though: good shops and top quality zinc plating plating are available.
Q. We are a small manufacturer producing specialty tools for industrial customers. We end up with a part mix that is fairly low quantity but lots of variety. Mostly mild steel and small enough to hold with one hand. Historically we've had them plated with yellow zinc, but it's been a real pain.
Hard to say which is the most painful issue but, lead time, cost, adhesion, bubbling, color, consistency from one week to the next, lost parts, missed deliveries, and more.
Considering that we spend $20-$30k per year for this, I'm wondering if there might be a plating/coating process we could do in-house and avoid some of those issues.
So...
Looking for a plating/coating process for mild steel. Needs to have at least some corrosion resistance. Needs to be reasonably robust that it doesn't come off under handling. Minimal dimensional change (maybe 1/2 thou ok) and most importantly, the process needs to suitable to add to a ~10 person shop.
So, is there a different process that might be suitable for our needs that we could run in-house?
-Thanks
for Shops, Specifiers & Engineers
from eBay, AbeBooks, or Amazon
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"Alkaline non-cyanide zinc plating with reuse of recovered chemicals" by Jacqueline M. Peden (1994)
from (U.S. EPA)
from eBay, AbeBooks, or Amazon
from eBay, or AbeBooks
from eBay, AbeBooks, or Amazon
from eBay, AbeBooks, or Amazon
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Engineering Lead - Tucson Arizona
November 15, 2024
A. Hi Denny, I understand your frustration. However, $20-$30K per year, even if it seems a lot to me and you, is nowhere in the range of what would be needed to justify bringing a process in house. And if you do in-house plating the regulatory issues alone will cost that much, while driving you crazy.
The basic problem is that painting or powder coating is probably inappropriate for tools, so you need a metallic process, and zinc plating is the least expensive metallic finish, so it is often associated with junk -- and there is a lot of competition at the low end, with quality often suffering.
What probably needs to be done, frustrating as it is, is to find a plating shop who will consistently deliver quality on time. You may or may not have to pay more, but there are such shops.
Alternately, you might search for a shop offering zinc alloy plating (zinc iron, zinc cobalt, zinc nickel). These finishes are somewhat more expensive than plain zinc and somewhat more corrosion resistant, so specifying such would at least eliminate some of the bottom-of-the barrel plating shops from the potential vendor list.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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