OM wrote in
:

On Mon, 28 Apr 2008 22:20:52 -0500, Damon Hill
wrote:

Yellow chromate primer to prevent corrosion of the aluminum?

...This makes sense, as the primer used on a lot of nautical items is
the same type. It does beg the next question as to whether or not the
red/white painting most gantry structures in the early days used was
also of a similar composition to provide the same service.

Might have started out as red and white lead paint, the idea being to
stand out to aircraft.

Well, from what I've seen of the salt haze down there, some daze it's
so thick that everything more than a few miles away turns the same
greyscale and blends together. Besides, I'm pretty sure lead paint
got banned decades ago; seems like even nitrocelluose aircraft paint
won't stand up to that and heavy UV for more than a decade. So, I
dunno what they'd be using now but it seems like you neglect that
stuff for too many years and it all starts to corrode dangerously,
hot-dipped zinc galvanizing or not... Maybe they're using some sort
of thick coat polyurethane or suchlike? There are conversion
coatings that are supposed to bond to corrosion and neutralize it.

Don't get me started on the buzzard droppings. Nasty stuff.

We need a local who actually works onsite; too bad Kim Keller's
moved on. I saw the 'milkstool' up close back in the 70's, but all
I remember it was a thickish grey paint.

--Damon