The best and cheapest protective paint I have found for galvanised and bare
steel is ordinary aluminium paint. It should cover the old paint effectively,
and from my experience it is more effective than Cold-Galv. I put my Rohn 25G
tower up in 1981, insulated with a used broadcast tower base insulator. The
steel castings on the ends of the base insulator are bare ungalvanised steel. I
gave them a couple of coats of aluminium paint before putting up the tower, and
have re-painted them only once since then. I have seen no more rusty spots
appear at the surface of the bare castings than what has appeared on the HDG
tower itself. I have also used aluminium paint to touch up a few rusty spots
that showed up on the galvanising.
I tried Cold Galv that comes in a spray can on some bare ungalvanised steel
fence hardware, and within a year or two rusty spots were beginning to peek
through. Re-painted with aluminium, several years ago, and it has remained
rust-free ever since. Last can I bought was a gallon of Rustoleum from a big
box store for about $26.
Another use I find for aluminium paint is that it makes a good primer for
galvanised steel. The farmer who leases cropland and who keeps the antenna
field mowed off accidentally bumped one of the guy anchors with his mower. No
permanent damage was done, but I decided to paint the equaliser plates and
turnbuckles bright John Deere yellow to make them more visible than the
unpainted steel. Problem was, the yellow paint wouldn't adhere to the
galvanised steel and almost immediately peeled off. I tried an undercoat of
Rustoleum aluminium, let that thoroughly dry, and then painted with the John
Deere yellow and so far it has stayed on, 3 or 4 years now, without peeling.
Don k4kyv
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