[TowerTalk] Mast material

[Roger (K8RI)]

k2vi wrote:
> Hey guys, can someone please advise me on the mast to use, I was looking at 2" EMT pipe I saw in the electrical dept at home depot. Keep in mind this pipe will be supporting a hy-gain 203BA which has a 16' boom and weighs 32# also it will be pushed up from the thrust bearing about 6'. 
The antenna is not much for the strength of 2" EMT BUT doing it with a 
6' arm is.  EMT is rolled and welded. It's not all that strong. It's 
also cad plated which will rust in a hurry.  Schedule 40 galvanized it 
much stronger. OTOH if you think schedule 40 is heavy, try some sked 
80.<:-))  I use schedule 40, structural steel tubing, but it has to be 
thoroughly cleaned, primed and painted.
> Im sure it will be fine here in va beach. Right now im using a galvinized 2" shedule 40 pipe that weighs a ton.
>   
You should try pulling 40' of schedule 40 to the top of a 100' tower and 
then lowering it down through the thrust bearing. <:-))

Given the choices the 2" pipe is a better choice. OTOH I'd have the ends 
cut off to eliminate any bare steel that will rust. then cap on both 
ends  to keep water/moisture and critters out. 2" can be capped using 
the tops of paint cans along with Silastic RTV (TM). OTOH I weld caps 
over the ends and then give it a real good dose of  LPS2 before closing 
the vent holes.

NOTE, be careful if you dose the pipe with a rust preventive and then 
weld the vent holes shut. It might get a bit noisy.  Better to drill and 
tap the ends for small pipe plugs.

73

Roger (K8RI)
> tony k2vi
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