Text 21887, 182 rader
Skriven 2006-01-11 10:10:00 av Michiel van der Vlist (2:280/5555)
  Kommentar till text 21764 av Roy Witt (1:1/22)
Ärende: Welding, brazing and soldering
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 >>> OK, I'll give you that one. We call that type of welding, with
 >>> a torch, using filler rod (here they're about 3ft long).

 MvdV>> here they are 1 metre long. Thickness 3 or 4 mm.

 > Yeup. 36 inches equals 3ft, 1m = 39 inches.

36 inches is too short for most of the elements for a 2 m. beam. One meter is
long enough except for the reflector. That should be 104 cm. I silver soldered
an extra 4 cm to that rod. I used a pice taken from the last director.

That was a 10 over 10. I later converted it to a 10 el cross yagi.

 > The thickness is the same, 1/8th to 5/32 of an inch, which
 > equals 3 to 4mm.

Close enough.

 > In contrast, the wire used in a wire fed MIG welder is about 1mm,

Yes, I have sen them but never used them myself.

 MvdV>> The ones used for brazing are excellent for making an HB9CV fox
 MvdV>> hunting antenne. I made many of them. I also used the steel filler
 MvdV>> rod to make antennas but they are no good for permanent use at they
 MvdV>> will rust.

 > You can prevent rust by spraying them with a clear coat paint.

For a fox hunting antenne that would probably ok. For a full sized antenna used
for transmitting I would not use paint on the elements. Paint has very bad hf
properties, it will absorb some of your transmitter power. So I used brass rods
for the 10 over 10.

 > It's non lead based, so the antenna won't know it's been painted.

It does not have to be conducting to absorb rf energy.

 > I made a stacked pair of Quagi's out of brazing rod. It too will
 > corrode, so I sprayed it with clear paint and they lasted a
 > long time. I used PVC pipe to make the boom

I used 5/8 steel pipe. The type that they used for electric conduits before PVC
came into use. I drilled holes in it for the brass elements en soldered them to
the boom with tin. I painted the boom, not the elements.

 > and that will deteriorate in the sun. Which is why they
 > don't exist today.

Right. Also PVC is not strong enough for a 10 el beam.

 > I should put a photo of those on a website sometime.

If you get the opportunity, please do. I can't show ypu a picture of my 10 el.
I dismantled it some time ago.

 MvdV>> We once made a dozen for the local scout group here to
 MvdV>> have fox hunt during a JOTA.

 > Alright.

For those I used steel rod. It's cheaper and they were meant to be used only
occasionally.

 MvdV>> So much for history. I have been lending my callsign to the local
 MvdV>> scout group for the JOTA for some twenty years now. This year, well
 MvdV>> last year actually, just before I was going to call them to remind
 MvdV>> them of the need to register, they called me to tell me that this
 MvdV>> time they would dispense with the JOTA part and do participate in
 MvdV>> the JOTI only. <sigh>

 > Time marches on.

It does. Sometimes I don't like where it is going. This was one of them. But
thereality is that ham radio is on the decline. It is not going as fast as
FidoNet, but it definitely is on the decline. We have very little influx form
the younger generation here. There are so many other interesting toys for which
they do not have to go trough the effort of getting a license for. :-(

 > I once led a club I was a member of in Poway, CA on Field Day.
 > Our score surpassed all the years before me and we did it
 > two years in a row. Then, the club got tired of doing Field Day.

Local club stopped doing field days as well here...

 > I then became the repeater custodian until they got tired of
 > maintaining it.

I was the custodian for the local 2 meter repeater PY3PYR for over ten years.
Then another group wanted to build a new repeater and so I let go. I was tired
of it anyway...

 > It was then that I realized their interests and mine didn't jive and I
 > quit. I went on to set up a couple of repeaters of my own, but sold
 > them a while later because I lost interest. One of them is still on
 > the air, high atop Mt Palomar in northen San Diego county.

I took the next step. I took a place in the nnational committee that
coordinated repeater frequencies in The Netherlands. Until I got tired of
settling all the diputes...

Now I am a member of the comittee that negotiates with the authorities on
amateur licence conditions. We have two national ham radio societies here,
VERON and VRZA. I represent the latter.

You can see a picture at: http://www.vlist.org/nera.jpg

I am the guy in the green jacket fourth from the left in the top row. The guys
kneeling in front are from "Agentschap Telecom" the Dutch equivalent of the
FCC. The guy with the red shirt on the right id the fourth delegate from AT. So
as you can see the hams got 3/4 of the "Dutch FCC" on their knees! ;-)

The picture was taken last year in the reciever hall of the main Dutch monitor
station at Nederhorst de Berg. (NERA). Toy can see some equipment in the
background. The occasion was that it was the last time our biannual meetings
took place at that location. The station is now disassembled and replaced by a
series of unmanned remote controlled station scattered over the country.

 MvdV>> I have a simple transformer for arc welding. 140 Amps
 MvdV>> maximum. I actually bought it for my son to practise,
 MvdV>> but he soon lost interest so I kept it for myself.

 > What do you use for rod?

I mostly use the "universal" 2 mm electrodes. The ones with cladding. The 2 mm
is the core, with cladding they come to just under 4 mm.

 MvdV>> I have some pictures of it that I still should put on my
 MvdV>> webiste on the "mistlamp op de kar" sub page. maybe I
 MvdV>> will find the time one of these days...

 > I'd be interested in seeing it.

You'v seen them by now.

 MvdV>> I never had that myself. But I have worked in an eye hospital
 MvdV>> and so I have seen the results of exposure to UV. Because it
 MvdV>> is not so much the brightness of the light as the UV that
 MvdV>> causes "welder's eyes". Doesn't happen if you are careful
 MvdV>> but if you are sloppy with the hood....

 > It wasn't that I was sloppy, it was because I was the setup
 > person and got the flash off the walls.

I see.

 > (I hadn't learned how to weld yet) I spent nearly 6 hours in that
 > weld shop, so I was hurting quite a bit the next day.

If you spent that long in it, you should have had some protection even if you
did not do the welding yourself. I say the person responsible was negligent for
not seeing that you did...

 MvdV>> And the slug around the electrode for arc welding...

 > Yeup. We call it flux rod, but you probably have a different
 > name for it.

We usually refer to them as "laselectrode". Th efull name would be "beklede
laseelectrode" ("dressed up welding electrode") but that is seldom used as the
other type, the naked rod is called "lasstaaf" (welding rod), so there is no
confusion.

 MvdV>> I have no experience with a torch for welding, just for brazing.

 > Well, clothes hangers are made of the worst steel you could
 > possibly find. You don't know what you're getting into until
 > you try that. It's nearly impossible to get a good weld with it.

So why didn't he use standard welding rod?

 MvdV>> With the electric arc welder, you don't see colours...

 > But you can see the puddle.

Yes, and that is where experience comes in. I have too little of that...


Cheers, Michiel

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