[TowerTalk] Homebrew tower

[Roger (K8RI) on TT]

I would disagree with a couple of caveats,  I'd remove the galvanizing 
with a sanding wheel. One of those constructed from strips of emery 
cloth or sand paper. Unlike grinding, they only remove the surface and 
are not prone to removing excess steel. or in the case of water pipe, 
malleable, or nodular iron.  The correct grit does a good job and leaves 
a good surface.  Like grinding, sparks indicate you have removed the 
galvanizing and are into steel.  OTOH you still need to carefully 
inspect the surface to make sure ALL of the galvanizing has been 
removed.  I don't like to do it, but I've welded a lot of galvanized 
water pipe and steel angle (windmill towers)

I do the work outdoors with a MIG welder and a light quartering breeze. 
A fan, or strong breeze requires too much cover gas, and is more likely 
to lead to aspiration: IE eddy currents carrying the noxious fumes back 
to the welder.  I've never bothered with the milk (I'm allergic to it) 
but with care I'm still welding at 75.
  When outside, be careful of buildings and shrubs causing eddy currents 
with unpredictable flows.  Many days around here the wind direction can 
be quite variable.

Don't get the galvanizing material into the weld It can reduce the 
strength of the weld substantially.  Another reason for cleaning off all 
the galvanizing "before" welding.  Poisonous fumes and weak welds. 
Reasons for not welding galvanized.

OTOH Solder is seldom anywhere near the strength of a proper weld.

Still, hams are noted for using what's available.  I started to say, 
"not long ago", but that only applies to those near my age or 
older<:-))  Instead, I'll say, "Used to be" we had articles on building 
towers and masts of wood 2 X 4s.  Even QST and the handbook had articles 
on them and we thought they were great.

Transmitters using a cheap pair of 6 L 6s.  Now a pair of 6 L 6s might 
cost more than a simple commercial transmitter.

So the materials may not be the best, but they are what's available.  We 
apply what we know, seek advice and try to stay safe.

73, good luck,  and stay safe

Roger  (K8RI)


On 6/26/2015 10:28 PM, Denis Coolican wrote:
> It is just about impossible to weld galvanized pipe.  You have to grind the galvanizing off of where you intend to weld it.  Then you can weld it.  When grinding once you see sparks you know that you have the galvanizing off of it.
>
> Use plenty of ventilation and drink some milk ahead of the time you will be welding it.
>
> Denis ve6aq
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-- 

73

Roger (K8RI)


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