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Re: [TowerTalk] Homebrew tower...

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Homebrew tower...
From: Patrick Greenlee <patrick_g@windstream.net>
Date: Sat, 27 Jun 2015 09:46:34 -0500
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Ventilation for welding galvanized.

Do not position yourself so that the fan is behind you blowing past you and then over the weld as eddies and turbulence will bring the welding fumes to you. Better to place the fan blowing at right angles to the line from you to the welding site. This blows the fumes away from you far better than other arrangements. Milk helps but isn't a cure-all for the poisonous gasses so be careful with ventilation.

It the fan arrangement seems counter-intuitive to you then watch some You Tube videos of welding and note how the visible fume plume envelops the operator.

Patrick

On 6/26/2015 8:31 PM, TexasRF--- via TowerTalk wrote:
Rick is quite correct about the danger of welding galvanized material.
Poisonous gases are released in the welding process.
Having said that, it can be done safely with plenty of ventilation and
preferably outdoors. Read that as a big fan blowing all the smoke and fumes
away  from the welder.
Using bolts on large round tubes can be a problem. The tubing will tend to
deform before the bolt is tight enough to hold a brace in place. Bolts with
  angles of course is no problem since the material is already flattened.
The horizontal and diagonal rungs in 25G are made of 3/8" rod which is
quite nice to work with. But, there is no reason that pieces of the 1 1/8"
material can't be used if you have enough. I have seen towers with round legs
and angle braces as well.
73,
Gerald K5GW
In a message dated 6/26/2015 7:17:02 P.M. Central Daylight Time,
richard@karlquist.com writes:

See:

https://www.flickr.com/photos/18794861@N00/2340109594/

The  "Mirador"

About 8 years ago when I was at the "Maker Faire"
(by Make  Magazine) there was an exhibit of a
tower made out of electrical  conduit.  Each
conduit had the end flattened with a hole
drilled  through it.  There were a series of
horizontal hexagonal "wheels" that  were supported
by diagonal pieces.  The wheels got  progressively
smaller as you went up.  The guy who built it  would
climb up the tower to take photographs.  The
spacing between  the horizontal assemblies was
something like 5 feet.  I guess this guy  assembled
the whole thing in situ at the Faire!  He told me
there  is some machine tool he used (it had a weird
name) that could either  flatten or punch holes in
the ends of the conduit.

The tubes you  have sound like "3/4 inch" water
pipe.  They are going to be more  difficult to flatten
and drill at the end than conduit, which is  designed
to be formed.

Unfortunately, it is dangerous to weld  galvanized
material, so you have to fasten it together  with
bolts.

Rick N6RK

On 6/26/2015 4:47 PM, Jim Lux  wrote:
On 6/26/15 8:50 AM, Douglas Ruz wrote:
  Hello,

I would like a tower in my property but i can  not buy a Rohn or any
other tower, so, I WILL BUILD ONE...or will  try build one.

I have many galvanized tubes, 7 ft  long, 1 1/32 inch diameter and 1/8
inch  wall.A

I have been reading dimensions of Rohn 25G and  45G...i like 25G.

My goals are:
-Reach  about 50 ft high.
-Install a rotator.
-Install a  lightweight tribander yagi (maybe an spiderbeam), a 6m yagi
(5  elem) and maybe 2 elem moxon for 40m...I know 50ft is not OK for a
  40m antenna but my anchor points are to close, so, i can not install  a
higher tower.

I have another important  questions...it is about GUY LINES...what is
the cheapest guy line  solution ???
if you have a lot of pipe/tubes, and enough  ground space for the base,
why not make a lattice self supporting  tower.  Think farm windmill (or a
Rohn BX) or power distribution  tower.

Big triangles, 3 or 4  sided.





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