[TowerTalk] 5. Re: Making an 80 meter vertical from Rohn 25

[Randy]

If you've seen construction crews assembling hundreds of feet of black 
or yellow pipe above ground, then
forcibly pulling the whole length through the ground, from one 
excavation to the next, that's HDPE.
They square off the ends of two lengths, heat them up, and hydraulically 
jam the heated ends together,
which makes an incredibly strong joint.

It is also used similarly in "pipe bursting", where they pull a new pipe 
though an existing line of
the same or smaller (!) diameter, "bursting" the old line out of the way.

In either case, they assemble a long, snake-like length before 
beginning, so, yes, it's pretty
flexible in that regard.

AFAIK, the black is generally water, and yellow is natural gas.

73,
Randy
KZ4RV

jimlux wrote:
> Art wrote:
>   
>> Can someonw please enlighten me, what is HPDE?
>>
>>     
>
> High Density PolyEthylene
> aka Poor Man's Teflon(r) (PTFE)
>
> Very low friction coefficient (not as low as PTFE), also melts at a 
> lower temperature.
>
> You'll also see UHMW PE (Ultra High Molecular Weight).
>
> It's great stuff. Excellent dielectric properties, easy to machine (if 
> you have *sharp* tools), works great as a bearing material for low 
> speeds (e.g. mast bearing).  Very inexpensive (cutting boards are the 
> most popular hobbyist source).  It's used a lot in homebuilt HV stuff 
> where the lack of mechanical strength isn't a big deal.
>
> Don't use it in a bending application (it's fairly flexible, and does 
> flow and/or take a set).
>
>
>
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