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topic 59831

Is supplier providing zinc coated iron tubes instead of aluminum?

March 29, 2015

Q. Good day all,

I am a trainee student engineer working for an importing company.

Recently, the import company suspects that its supplier are cutting down costs by replacing aluminium tubes by using zinc coated iron tubes. These tubes are used to package super glue. We received a different tube from a different supplier who claims it to be aluminium; which has more "shine" to it and requires greater force per unit to crush compared to the original tube; later supplier reckons we are being shipped zinc coated iron tubes and not aluminium.

My initial approach was to dip the "zinc coated iron tube" in hydrochloric acid to see if I can get zinc coat off. This will get me started on my journey.

I would hugely appreciate any alternate cost effective methods to be provided?


A Sach
Trainee Engineer - Australia

March 2015

Hello A.

Quick reaction with HCl might be indicative of possible zinc plating, but would not be conclusive even as a first step because the plating could be something else like cadmium. Suppose it was cadmium and your company was sued for causing cadmium poisoning?

Such possibilities warn me of a few things: firstly, that you must deal only with reputable suppliers; secondly, that you must demand that your suppliers certify exactly what they are providing; thirdly that, despite any wishes for "cost effective methods", if you feel a need to do tests, they must be good ones.

After you have a detailed specification of what the supplier claims they are providing, we can hopefully offer some testing ideas. Good luck.


Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

simultaneous March 30, 2015

A. Why don't you just check it with a magnet?

William Doherty
Trainer - Newcastle, NSW Australia

March 30, 2015

A. Try a magnet to see if it is steel.

Tom Rochester
Plating Systems & Technologies, Inc.  
supporting advertiser
Jackson, Michigan, USA
plating systems & technologies banner ad

March 30, 2015

A. Have you tried a magnet?

Kris DeBisschop
- Stratford, Connecticut

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