The reason this sort of intrigues me is because in 1983 I had to drop a
rather new 410' tower in an AM array due to rusting from the inside
out. The forensics of the aftermath showed that apparently the tubes
were galvanized prior to welding. The process of attaching the cross
members burned off the galvanizing on the inside, causing it to rust
from the inside out. Some of the holes, (especially in the 300 to 400'
region), were the size of a pencil eraser.
I have a 26 year old American tower, so I'm a little concerned.
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