[TowerTalk] Aluminium Paint versus Cold Galv

[Donald Chester]

Was yours applied with a brush or mitt, or was it spray-on? Maybe the spray stuff is less effective.

My 33 y.o. tower could use a paint job, since in some spots the galvanising appears to be completely gone, leaving a layer of dark brown surface rust. Not to the point of scaling or flaking; with aluminium paint or rusty metal primer I would just apply it right over the rust which would be about right to assure a strong bond. I wouldn't attempt to wire-brush an entire standing tower in any case.

My tower is 127' of Rohn 25. Would anyone have any idea how many gallons of paint it should take, using a painter's mitt?


Don k4kyv

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I only have experience with the ZRC cold galvanizing compound.  When I first read your post I thought what a good time to review my old chemistry and valence bonding etc.  After looking up the valence shells for AL, FE, and ZN I thought, screw that I'll just offer my opinion.

I painted my Rohn 45 20 years ago with a couple of quarts of ZRC cold galvanizing.  The cans are heavy and the contents look like liquid zinc.  ZRC says it is about 95% zinc flakes.  Looking up their FAQ they claim that it does perform the galvanic bond as the flakes bond together and the carrier dries.

In my case I painted it over an already painted red/orange and white transmitter tower.  I power washed the tower first and knocked off as much of the paint as I could, cleaned up any small rust spots and then painted it with the ZRC.  The ZRC is tough stuff.  It hasn't flaked in 20 years/2 QTHs and if you pull a rope over a wrung it will polish the spot to a shiny silver bare metallic sheen.  I would have to agree that the stuff bonded well to the tower.  I suppose I could make some ohmic measurements from inside surface to outside surface the next time I have it down and see if it is electrically bonded as well but don't expect that measurement this week.

Earl
N8SS