FAQ: What is Galvanizing?
-- and what if the paint won't stick?
What is hot-dip galvanizing?
Iron and steel rapidly rust and corrode. An excellent way to deter rusting for a very long time is to hot-dip galvanize the parts, that is, to dip them in molten zinc (rather like dipping strawberries in chocolate).
Top Articlesrefrigerator dent repair aluminum oxidation removal oneida icarus flatware house smells like mildew how to clean tarnished metal sterling silver vs silver used catalytic converter prices pure silver watches how to clean bathtub stains how do you get scratches out of glass how to remove white watermarks from wood stainless steel scratch eraser kit cast iron cook stove respirator for acid fumes why is copper used for electrical wiring calphalon hard anodized muriatic acid respirator how to clean an old stained bathtub whiten toilet bowl how to get rid of musty smell in house
Why is galvanizing such a good rust-preventer?
Galvanizing is a great rust preventer for several reasons:
What are the down sides of galvanizing?
Can galvanizing be reliably painted or powder coated?
Yes, galvanizing can be painted, but it may not be easy -- especially if painting was not anticipated when the parts were galvanized.
If you are a homeowner or hobbyist trying to paint a galvanized surface, the best advice (compiled from dozens of public forum threads on this site) seems to be: clean the surface with a scrub brush and a detergent like trisodium phosphate (TSP), rinse, neutralize the detergent and acidify/etch the surface with diluted vinegar, rinse, apply epoxy or a self-etching primer made specifically for galvanized surfaces; avoid alkyd paints
If you are a manufacturer, the above will not be good enough! The best plan, used by auto manufacturers, is to employ galvanneal steel rather than galvanized steel if you intend to paint it. Galvanneal has been annealed after galvanizing in a way that causes the steel and zinc to interdiffuse so that you are painting a steel alloy rather than pure zinc.
Manufacturers may also wish to skip the chromate final dip if the parts will be painted because the brightness this dip imparts will not be required for painted parts. In any case, the galvanized or galvannealed steel must be phosphatized before beginning the painting process.
For detailed information on painting galvanized steel,
manufacturers and specifiers should see "Duplex Systems:
Painting Over Hot Dip Galvanized Steel", which can be
downloaded as a '.pdf' file free from the AGA at
This is only a very brief intro to galvanizing. Here is a partial list of related threads/ letters on the amadeya42.com Hotline public forum:
Back to amadeya42.com Home Page