Replies

1. 
   popawheelie | Oct 13, 2007 06:18am | #1

   I would wash them with a detergent first to get any oils off of them. Then etch them with something like the vinegar to give them some bite. I would rinse them off.

2. 
   canoehead2 | Oct 13, 2007 03:43pm | #2

   I haven't done this myself but have heard that some use diluted muriatic acid (HCL).  Maybe vinegar isn't acidic enough to etch the galvanized surface enough.  Sorry, I don't know how dilute to make the muriatic though - too strong and I guess you might strip it all off!

1. 
   seeyou | Oct 13, 2007 05:19pm | #3

   Yeah, muriatic is a bad choice. Use vinegar and rinse well or use a product like Galvaprep ( I haven't done any galv. gutters in years, so I haven't bought any lately, but paint stores sold it).http://grantlogan.net/

    

   I was born in a crossfire hurricane..........shooby dooby do

3. 
   davidmeiland | Oct 13, 2007 05:50pm | #4

   I had galv gutters made for my house. Scrubbed them with vinegar and then primed with a special galv primer. I had to search for it, and it was not an ordinary housepaint primer. The paint has held up extremely well.

1. 
   seeyou | Oct 13, 2007 06:08pm | #5

    "Scrubbed" them with vinegar

   Scrubbed may be the key word to success.. http://grantlogan.net/

    

   I was born in a crossfire hurricane..........shooby dooby do

1. 
   davidmeiland | Oct 13, 2007 07:36pm | #6

   There is some resistance as the scrubber moves over the oily areas, and then it's easier as you go back over an area with no oil. Learning curve = 5 seconds.

2. 
   sawduster | Oct 13, 2007 07:42pm | #7

   I assume you mean a 'scotch pad' type scrubber.

1. 
   davidmeiland | Oct 13, 2007 07:47pm | #8

   Correct, stolen from the wife.

4. 
   JohnD1 | Oct 13, 2007 10:10pm | #9

   I have worked with paints in another life, including painting galvanized. There are several problems with painting galvanized, all correctable.

   1. NEVER use oil paints. The resin in oil paints will slowly react with the zinc in the galvanizing to form a compound that does not adhere to the metal. This is why you see paint flaking from indoor piping.

   2. There are residual coatings on the galvanizing. It might be oil, or it might be the material that they put in the zinc bath to help keep dross down. In either case, scrubbing with vinegar will certainly help. It will also etch the surface on a microscopic level.

   3. Fresh galvanizing is really smooth, and paint does not like smooth surfaces. Mechanical abrading really doesn't change the "tooth" of the metal as the grooves are really huge compared with the molecules of paint. But it does remove surface junk. See #2.

   The best way to paint galvanized is to use a primer specifically designed to stick to galvanized. My experience has been extremely good this way. They only thing that I insisted was that the production people wash the surface. My Mantra: "The paint sticks perfectly well to the dirt. Unfortunately the dirt does not stick to the substrate".

5. 
   Jay20 | Oct 14, 2007 05:16am | #10

   I use to work in the metal furnishing industry. Galvanized steel is just zinc plated steel. The rub comes in in a number of areas. To cheaply extend the salt spray time ( so they can claim good rust prevention results) they add  an oil coating. This doubles their results. This oil coating must be removed.  The next is that zinc oxidizes easily. This and it is low on the galvanic scale is why it is used and is effective. Also zinc plating is very smooth. After removing the oil use a Scotch Pad as was suggested earlier. This will remove some of the oxide and scratch (give it tooth) the surface. Then use a metal primer preferably one for galvanized steel. Do the above the finish will last a long time and look great. Properly painted galvanized steel will last many years.  Jay

1. 
   sawduster | Oct 16, 2007 12:10am | #11

   Thanks everyone for the advice. I'm going to vinegar scrub, rinse, and then prime with a galv primer. Now if the rain would stop...