Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Priming / Painting Galvanized Gutters
Q. A simple question that I hope you will answer for me. I have just installed galvanized steel guttering on my home and want to know what preparation (priming) I need to do before painting. I have heard that vinegar
⇦in bulk on
eBay
or
Amazon [affil links] can be used to etch the surface. I also have muriatic acid
⇦this on
eBay or
Amazon [affil links] . What dilution? What type paint do you recommend?
Thank you very much for your help.
retired
1996
A. Hi, John.
Muriatic acid will dissolve (ruin) the galvanizing quickly and should not be used.
Vinegar is not as strong, and some people find it helpful. Getting really good adhesion on galvanizing is difficult! The American Galvanizers Association at www.galvanizeit.org has some info, but TSP (
⇦this on
eBay
or
Amazon [affil links]
) and a
⇦this on
eBay or
Amazon [affil links] , possibly followed by the vinegar, and definitely followed by a Galvanize Primer
⇦this on
eBay or
Amazon [affil links]
[affil links] should be a good answer for personal use. Good luck.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. I am building a mini ramp (half pipe) for skateboarding and I am going to be covering the ramp with 22 gauge galvanized steel. I have heard that a latex primer is best to use on galvanized steel for skateboarding because it adds more grip. Do you have any suggestions on a good latex primer for galvanized steel. Also I have heard you can clean the galvanized steel off with water/rubbing alcohol mix, would that work?
Thank you
Bryan
Woodard - winston salem, North Carolina
September 20, 2012
Hi, Bryan. A latex self-etching primer should be satisfactory.
If you put a top coat on it, avoid alkyd paints as they are incompatible with galvanizing.
Rubbing alcohol is not a very powerful solvent; I think scrub brushing with TSP would be far more effective in getting the metal clean before painting. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 20, 2012
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