[TowerTalk] Insulating towers

[Jim Lux]

On 12/26/13 12:36 PM, Charlie Gallo wrote:
>
> On 12/26/2013 Patrick Greenlee wrote:
>
>> Any thoughts on insulating a tower?  I have some Rohn 25 that I want to use
>> to make a home brew version of a Hy-Gain Hy-Tower multi-band vertical.  I am
>> considering two approaches:
>
>> 1.  Buy a plastic cutting board to cut up for material to home brew
>> insulators to be electrically between the tilt base and the tower proper. (I
>> have a friend with MS Mech Eng and 35 years hands on experience who will, if
>> asked, consult on this or help me design it.)
>
> The issue with plastic cutting boards is that they are made from High Density Polyethylene (HDPE)  HDPE will "cold flow" (technically called Creep), and is known for "Poor weathering resistance"
>
> You may want to look at one of the "filled" versions, or some other filled engineering grade plastics - or use something like PEEK, PES or even Phenolic
>

Definitely..
Get something that is designed as a structural material.
http://www.mcmaster.com/#fiberglass-hollow-rods/


You may find that it's easier to just buy the premade insulators than to 
figure out how to fabricate something out of the raw materials.

To a first order, structural fiberglass is a lot like aluminum, in terms 
of strength. It's a lot less stiff, though.

There are very nice structural, electrical insulators out there that 
look like a lump of plastic with two threaded bolts sticking out of it. 
  The trick, as always, is knowing what breakdown voltage you need, and 
designing for that.