topic 0 522

Priming / Painting Galvanized Gutters

(1996)

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 can be used to etch the surface. I also have Muriatic Acid [linked by editor to product info at Amazon]. What dilution? What type paint do you recommend?

Thank you very much for your help.

John Rohde
retired

Latex Self-Etching Primer

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 (trisodium phosphate [linked by editor to product info at Amazon]) and a scrub brush, possibly followed by the vinegar, and definitely followed by a Galvanized Metal Primer [linked by editor to product info at Amazon] should be a good answer for personal use. Good luck.

Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey

September 20, 2012

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

Bryan Young
Woodard - winston salem, North Carolina

A. 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.
finishing.com
Pine Beach, New Jersey

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