[TowerTalk] F12 C19XR Rivets

Tue Mar 8 19:33:15 EST 2016

There is plenty of overlap between the tubes to be riveted and they are 
a nice slip fit.  The sections to overlap are coated with Penetrox-A and 
inserted to the proper depth.  The line of rivets pull the two tubes 
into an intimate contact.  It appears to me the electrical connection is 
primarily between the tubes rather than the rivets. Two rows of 3 rivets 
on opposing sides provides a large surface area of contact, while the 
Penetrox-A keeps the contact area clean and free of oxidation..

This is a reassembly, so I may give the joint areas a good cleaning and 
polishing before the reassembly although the joint areas look pretty good.

73

Roger (K8RI)

On 3/8/2016 Tuesday 3:22 PM, Bert Almemo wrote:
> I learned long time ago that using pop rivets, blind or not, don't make for
> a good electrical connection. For all antennas, using aluminum tubing, I've
> used self tapping screws for the last 30 yrs and it's served me well. It's
> also much easier to take antennas apart and put them together again using
> screws. As always, OMHO!
>
> 73 Bert, VE3NR
>
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Roger
> (K8RI) on TT
> Sent: Monday, March 07, 2016 11:53 PM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] F12 C19XR Rivets
>
> Good advise Jim,
>
> My C19XR uses 3 rivets in a row at each element joint.  I understand
> that they may have gone to 6 using two sets of 3 opposing rivets.
> That's the way I plan on repairing the ends of the 20 m reflector.
>
> IIRC it does use larger rivets in the boom, but I don't remember the
> size as I had forgotten the size for the elements..
> After tomorrow (63F and 55 F for a low, 59/43 and near an inch of rain
> Wed) The snow should be gone giving me easy access, if a bit squishy, to
> the antenna.
>
> These are what are called a "Blind Rivets" in that, unlike regular pop
> rivets which have the mandril go all the way through, the end of the
> rivet is solid to prevent water from leaking through, much like the
> "Cherry Rivets" used in aircraft.  The "Sonex" little single seater has
> all riveted joints using these "Cherry rivets" instead of the typical
> flush rivets requiring a bucking bar.
>
> As Jim says, do not tap rivets in by taping on the mandril. Usually you
> only forget once as the mandrel may just fall in and you no longer have
> a blind rivet that may be a bit difficult to remove.  Trying to drill
> out a failed rivet can be frustrating as they often just spin in the
> hole instead of holding for the drill bit to cut metal.
>
> 73 es thanks Jim
>
> Roger (K8RI)
>
>
> On 3/7/2016 Monday 10:54 PM, Jim Thomson wrote:
>> Date: Sun, 6 Mar 2016 19:39:29 -0500
>> From: Larry <lknain at nc.rr.com>
>> To: towertalk at contesting.com
>> Subject: Re: [TowerTalk] F12 C19XR Rivets
>> Message-ID: <56DCCDC1.2020308 at nc.rr.com>
>> Content-Type: text/plain; charset=windows-1252; format=flowed
>>
>> In the early days C3, EF 180B, and 240 generally used 0.125 inch rivets
>> on the elements. The 180B had some 0.25 inch rivets as well if I recall.
>> Booms used 0.25 inch rivets. The C3, for example, generally had 3 rivets
>> per joint in the elements. I don't know how different the XR series is.
>>
>> 73, Larry  W6NWS
>>
>> ##  on my F-12 340N,  520, 615, EF-180B, and F12 shorty 44 foot 40m yagi,
> all the rivets
>> are .125, aluminum, and slightly domed heads,  with steel mandrels.  The
> shorty 40m
>> els used longer .125" rivets on the inboard portions only, where they are
> triple walled.
>> ##  The EF-180B  used  .1875  rivets on the else....  but only in one
> place.... like that huge swedge.
>> All the booms  used  .1875  rivets on the factory end  of each
> splice...where as the end user
>> portion of each boom splice used 1/4-20 SS  bolts  + nylocks.
>>
>> ##  No  .25  rivets were used any where.   Although those small hand
> riveters will pull a .1875
>> rivet, they are very tough to pull.    I bought a larger, looks like hedge
> shears,  type of riveter,
>> made  by pop company, aprx 25 inches  long,  to do the .1875 rivets.  The
> same longer riveter  will also do
>> .25  rivets, and also .125 rivets.   But the big riveter is too awkward
> for the .125 rivets, the small hand
>> riveter is better for that job.
>>
>> ##  POP  co also makes a hand riveter, that uses  90 psi from ur
> compressor, to pull any size of rivet, it also
>> has an optional device to collect all the spent mandrels.
>>
>> ##  DON'T  put any anti oxidant  grease on any rivets.... only the els
> overlaps.   Install ALL the rivets at any
>> joint before you pull any rivets.    IE:  install 3 x rivets in a row,
> then pull them one at a time.   And if rivets  2+ 3
>> start to back off, after pulling the 1st one, you have to tap the rivets
> back in, so they are flush, b4 pulling them.
>> Tap them back in via the domed heads..and NOT the mandrels.
>>
>> Jim   VE7RF
>>       
>> _______________________________________________
>>
>>
>>
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>

-- 

73

Roger (K8RI)

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