Summary for hot dip galvanizing electrogalvanized metal Discussion
Hot dip galvanisation of already electrogalvanised frames was discussed as a lower-cost alternative to 304 stainless steel for seaside safari tents. Julien Gufflet of Mauritius said the supplier warned the electrogalvanised frames would not suit a marine environment and quoted an extra US$3500 for stainless. Ozge SARACOGLU replied that hot dip galvanized parts last longer than electrogalvanized ones, though seawater contact can still require re-galvanizing and may leave a white-rusty appearance. He suggested epoxy painting after hot dip galvanizing as a cheaper option than stainless. Another answerer clarified that “electrogalvanizing” often means zinc electroplating, which is much thinner than hot dip galvanizing, and said the thin electroplated layer would be stripped during the acid cleaning stage of HDG anyway. He recommended polyester powder coating over galvanizing, noting epoxy’s UV sensitivity, and said powder-coated HDG should still cost less than 304 stainless.
Q. Hi,
I am about to buy some safari tents for a small tent lodge hotel that I am starting.
The frames of the tents have been electrogalvanised only.
The supplier is telling me that it is not suitable for the sea side region where my lodge will be located.
He is proposing to upgrade to stainless steel 304 but he is quoting US$3500 more. Not workable as per my budget.
I am thinking to apply a hot galvanisation bath onto the already electrogalvanised frames … can I do that ?
If anyone can help me. Thanks. Julien
Julien Gufflet
– Mauritius
A. Hi Julien;
Hot dip galvanized parts will last longer than electrogalvanized ones. But again it will require re-galvanization if any contact occurs with seawater. Moreover surface will have some white-rusty finish.
You can find a research in AGA’s site about corrosion rates:
www.galvanizeit.org/about-hot-dip-galvanizing/how-long-does-hdg-last/in-the-atmosphere/service-life-time-to-first-maintenance/atmospheric-corrosion-data/#generalRates
You might also try painting with epoxy after hot dip galvanizing. It would be the best option and still cheaper than stainless steel.
Ozge SARACOGLU
– Ankara, TURKEY
September 27, 2012
A. “Electrogalvanizing” is a term that mostly creates confusion.
It often means zinc electroplated.
Corrosion protection using zinc is proportional to the thickness of the coating.
Electroplated might have typically 10 microns of zinc, hot dip galvanized might have 100 microns.
To Hot dip galv a previously electroplated item isn’t really any problem. In the usual acid cleaning part of the HDG process, that thin electroplating will strip off in no time.
You could consider polyester powdercoating over the galvanizing. I think that would be better than epoxy, given that epoxy is UV sensitive.
Even powdercoated HDG will be cheaper than 304 stainless.
Geoff Crowley
Crithwood Ltd.
Westfield, Scotland, UK
October 4, 2012