[TowerTalk] Aluminum tower welds...Old Data circa mid 1970's ..........

[W5LT]

It appears you had a lemon. Welding of Aluminum is not something for the
casual do-it-yourselfer. The process requires special equipment (Heliarc) to
fuse the aluminum in a non-oxidizing environment (Helium) and special
training of the operator. I am sure Universal uses that process, but the
workmanship is also subject to operator variations. Perhaps you got a test
model of a beginning welder.  
I had an older design aluminum tower (1964) that developed a few cracks, but
as it turns out it was overloaded; the ratings of some tower manufacturers
are questionable.  I now have a new design Heights tower (c. 1997) which is
quite beefy, and is designed according to the UBC1997 structural
requirements by a Professional Engineering company. 
Interestingly, when I was preparing to upgrade my old installation to a
heavier design and asked Universal for their engineering design
calculations, they were unable or declined to provide them. 
73s
Bob, W5LT

-----Original Message-----
From: res1q6fs [mailto:roger.white at verizon.net] 
Sent: Sunday, February 24, 2008 7:50 PM
To: towertalk
Subject: [TowerTalk] Aluminum tower welds...Old Data circa mid 1970's
..........

I have been reading the aluminum tower threads recently and thought I would
add some data on the aluminum tower I had a number of years ago, maybe
before some of you were born!. Anyway, in the early 70's, I wanted an
inexpensive, self supporting tower as I did not want guy wires. I settled on
the Universal 50 ft. model whose size was rated well above my TH3 wind load
was going to provide. I had the tower for 5 to 6 years and was climbing it
one day to service the rotator. Well, as I was readjusting my climbing belt,
I looked down at my feet and saw something that was incredible. The weld
joints of almost all the welds above 30 feet were starting to crack, some
were sizeable (a few that I saw had at least a 0.1 inch gap)  and some were
hairline, just starting. Needless to say, I set a worlds record for coming
down off the tower. I decided to take the tower down and replace it. I sold
it to a ham that had experience in welding aluminum and he was happy to get
a cheap tower! I eventually upgraded to a Rohn 25 48 ft. fold over and now
30 years later have the UST HDX555, a fine, well built tower, my first crank
up. Hopefully, they are making the aluminum towers better and I had a fluke,
but I personally would think twice now before I would use one of these for
any length of time. Maybe I had a lemon, who knows. The tower had plenty of
margin for a TH3 and that was all I ever had on top of it and it saw no
ultra high winds.

 

W5RD

Murphy, Texas