[TowerTalk] tower painting, etc

[Kurt Andress]

Mark, Mmoon3@aol.com wrote:

> I need more feedback on a few questions regarding my 60' 45G going up soon.
>
> 1.  To blend with the sky, what color and type of paint is recommended for the
> tower?  I don't want the Rohn white or orange stuff.

The FAA makes certain tower owners mark their towers for enhanced visibility in
areas around airport or when the towers are over 200' high. Rohn offers these
obnoxious colors to meet this requirement. Most other towers that are not required
to meet the FAA marking demands do not paint them. Not really Rohn's fault that
they do not offer the ultimate invisible paint scheme. I would suggest that they
haven't been asked very often for it!Pick your favorite color match to your sky
from any rugged exterior paint. The stuff that really lasts is very expensive
(greater than $100/Gal) and is usually a polyurethane coating used for painting
aircraft or sea going vessels. That's the easy part! Getting any paint to stick to
the galvanize is tougher. I remember that there is some kind of phosphate solution
that will etch the zinc plating to allow the paint to properly adhere. Can't
remember the exact name. Maybe a TT subscriber knows what it is, or Rohn may be
able to tell you. It is also possible that the Rohn coatings contain something to
help solve the problem.

> 2.  Is the AG2 top section the best fit for a 2" OD mast?  I will be using a
> thrust bearing somewhere, depending on if I use an AG4 or AG2 top.

The AG2 section has a 2.08" inside dia. that works well with 2" OD masts.The AG2
will cause more binding and friction, requiring more rotor power, when the wind
blows. The AG4 with a properly protected pillow block bearing, that can rotate
when the mast bends, will require less rotor power when the wind blows

> 3.  Is Rohn quality going down?  There is a lot of excess galvanization
> "dripping" off the z cross members, and most of them are darn sharp!  The tube
> legs need to be filed-down so they will mesh with the adjoining sections.  Has
> it always been this way?

Don't know if this has gotten worse over the years. Haven't climbed one yet that
didn't have a hook somewhere. The guy, like you, who cares about it, files or
grinds them off before erecting the tower.

> 4.  Is anyone using utility-pole type long (4') fiberglass insulating rods at
> the top of their towers?  Could they be treated as pseudo-torqe arms?

I don't really understand this question. I wouldn't even think of using them as
torque arms. Good fiberglass is as strong as mild steel (35,000 psi Yield). But,
the stiffness is approx 1/10 of steel. This would render them useless to stabilize
the tower torque.

 Kurt

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