Date: Sat, 12 Mar 2016 10:53:02 -0600
From: Kevin Stover <kevin.stover@mediacombb.net>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] F12 C19XR Rivets
### back in the mid 80s...Alcan here in canada, devised a method to weld
aluminum...
as in super thin stuff.....including aluminum foil used by your wife in the
kitchen.
The idea at time was to use the new process.... for aluminum car bodies.
Obviously u wouldn’t want to pop rivet cars bodies together. They had it all
down to a fine art. When US steel found out about the proposed aluminum
car body manufacturing method, they went beserko, and the politicians
quickly finished off the idea....never to be mentioned again. Rust
doesnt sleep..and aluminum doesn’t rust.
## On a side note, I asked the local mobile aluminum welding guy here in town
about coming here to weld some thicker wall boom material and other items for
me,
like channel al etc. He told me that IF you don’t require any kind of
electrical connection,
a special kind of glue can be used.... that is one helluva lot strong than any
welding process.
‘Only god can get it apart’ he tells me. They now glue motor bike frames
with it..and also bicycle
frames etc. It works too, but no electrical connection, and it cant be
taken apart, has to
be cut off. Ironicly, its being used on exotic al car bodies.
## On my f12 40m boom, they weld every 120 degs.... where the boom drops
from
3 inch od...down to 2.5 inch OD. A short length of 2.5 inch OD is sid over
the end of the
2.5 inch tube.... then welded every 120 degs. So u end up with a stepped
reduction,
and the boom drops from 3 inch to 2.5 inch. No taper used. Then 1/4-20
SS bolts
and SS nylocks used to bolts the 3 inch and 2.5 inch booms together. Where
the bolts
pass through.... it’s a total of .375 inch thick material.
## Somebody actually makes tapered aluminum tubing. I saw it on the other
side of town,
used for marine applications. Perfect taper from 2 inch...down to .5
inch......and overall length
was aprx 20 ft. Then a 2nd tapered piece, but bigger OD at each end, was
used to splice
to smaller stuff. So the entire marine vertical was just 2 pieces. So it
can be done.
They can also taper the wall thickness..from thicker at the big end..to
thinner at the smaller OD end.
Dunno who makes it nor the process used.
Jim VE7RF
Someone would surely have to do a full on metallurgical analysis to be
happy with the resulting Yagi.
I have read every post of this discussion (God help me) and have noticed
a couple things.
Some of the folks in this discussion really, really, need to get a hobby.
My uncle, a former Collins engineer with an EE PhD told me once that the
first class all prospective engineers should be required to take is when
to and when not to "engineer".
I may be wrong but I thought I saw a recommendation to weld the tubing
joints?
I'd be willing to say the vast majority of members on this list, with a
few exceptions to be sure, have neither the necessary skill or equipment
to pull that off without blowing big holes in the aluminum and spending
a lot of money fixing stuff they "created". If done correctly it would
result in a joint that will never come apart, ever.
Just build the antenna the way the manufacturer intended and enjoy using
it, simple.
I guess if one really wanted to be picky, the ultimate solution would
be to invent a device that could extrude tubing on site with a built-in
taper.
No joints! You could build your yagis the same way eavestroughers
manufacture seamless gutters on site. With enough adjust ability to the
extruder, you could even manufacture one-piece booms.
73, Kelly, ve4xt
PS: the on-site extruder was a joke. Please, no comments on whether the
metallurgy is sound! Sent from my iPad
--
R. Kevin Stover
AC0H
ARRL
FISTS #11993
SKCC #215
NAQCC #3441
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