[TowerTalk] how much rust is too much?

[David Gilbert]

Hhmmm ... going only by the photo, I can't believe that there's enough 
good steel left there to properly support that tower.  The rust is bad 
enough to be crusty and flaking off, and if half the steel was left 
unsullied I'd be surprised.  Again ... going only by the picture.

I'm sure there are ways to reinforce that bottom section, but if that's 
really a plate over a pier pin I'd have to wonder what's under the plate 
as well.

Just my initial impression ...

73,
Dave   AB7E




On 10/13/2014 7:29 PM, Matthew Kaufman wrote:
> I've just acquired a property with a 150 foot tower, appears to be 
> Rohn 45, guyed at 5 levels. It was installed in the early 1970s(!).
>
> Prior to climbing the tower, I want to be sure it is safe. I've 
> excavated along the guy anchors down to concrete, and they appear a 
> little "crusty" but not more rusted than that. Still need to check the 
> very edge where they meet the concrete close-up to see if it is any 
> worse there. Not sure if I should try removing the rust or just leave 
> as-is.
>
> The base of the tower is a pier-pin base on concrete with the tower 
> bolted to the base plate. Some time over the past decades, dirt fell 
> down a slope and covered the base plate and the bottom bit of tower 
> (less on one leg than the other two). Near the surface I can just see 
> that the galvanizing has worn through, but below that there is 
> progressively more and more rust. The tower still feels solid, and 
> I've been working on removing the rust to see how much material loss 
> there is and it doesn't look *that* bad... but how do I know how much 
> is too much? Can I measure the diameter of the leg after removing the 
> rust and compare to the non-rusted portions of the tower?
>
> As far as removing the rust, I got some of the thin areas cleared with 
> a chelating rust remover gel, and the rust on the base plate cleared 
> with a stripper wheel on an angle grinder, but I'm thinking a small 
> sandblaster might be the best for the legs themselves?
>
> Picture of the base immediately after uncovering it, before removing 
> any dirt or loose rust: http://www.matthew.at/tower-base.JPG
>
> Picture of one of the three guy anchors: 
> http://www.matthew.at/guy-anchor.JPG
>
> Any and all suggestions welcome.. obviously I'd like to salvage as 
> much of the current install as possible, but I don't want it killing 
> anyone either.
>
> Matthew Kaufman, KA6SQG
> matthew at matthew.at (mailing lists)
> matthew at eeph.com (personal)
> http://www.matthew.at
>
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