478E9461-D32D-4B34-9482-599C58B52650.jpeg (59.13 KiB) Viewed 1346 times
Was hoping asking this question folks that work at ERI or Dielectric are in the forum somewhere and see this. Or if anyone else in the tower industry that has also worked hands on in what we call in the radio/tv/broadcast tower industry "Hardline".
Hardline essentially in its most general form is a tube of copper most the time in 20' lengths, can come in other legths, as well as 90° elbows, etc... And what they do is send broadcast frequencies from a transmitter room to all the way up the tower to an antenna that sends radio/tv through the air like magic. At the ends of the copper tubes are brass flanges that appear to welded, not soldered (appears). So to get to the question. Has anyone done welds like this? If so what process, air, filler metal, etc... when doing this.
NOTE: I have seen it done with solder and a torch, and it looked nothing like these neat dabs.
That's pretty cool. I guess that's basically just an enormous RF waveguide. We used smaller ones in the Navy for our radar systems, and I do believe the couplers were all soldered. Obviously, that large one in your picture does appear to be welded, and I would guess TIG welded at that. Or perhaps TIG brazed. Interesting.
Alright, I'll stop talking and let someone who actually works on those things provide some input.
I"ve TIG welded copper-to-copper, and brass-to-brass. But not copper-to-brass. I suspect you can use silicon bronze as a filler. Perhaps not for a specialized application like that, but for general projects. Brass off-gasses zinc when puddled, and it sucks.
@ Spartan I’m genuinely stoked it’s common knowledge on waveguide /hardline. We have a few different types of waveguide in my industry. Some is in the form coax cable and the other are these huge aluminum cylinders that are rectangular in the center.
"I don't buy things with money, I sell hours off my life to a job that when it's all said and done may never had paid enough"
That's been tig brazed with either silicone bronze or aluminium bronze using the cup walking method by someone who knew what they were doing. Very nice clean work.
@oscar noted, and thank you for the reply. These are heat sensitive. Any warp, dent, scratch, burn, dirt can and probably will knock off the fine tuning. And possibly cause a “burn out” all the more reasons I want to start making some custom pieces. Lol
"I don't buy things with money, I sell hours off my life to a job that when it's all said and done may never had paid enough"
Coldman wrote:That's been tig brazed with either silicone bronze or aluminium bronze using the cup walking method by someone who knew what they were doing. Very nice clean work.
No doubt, that is very nice work. I'm 99% sure it's been cleaned up after the fact---when brass puddles and gives off zinc, it coats everything nearby with black and white soot that ruins gas lenses FAST! Ask me how I know. Only standard collet bodies from now on.
In my experience welding copper, I find you really have to fixture it up well with chill blocks or you just anneal it something terrible. That looks like beautiful work that never affected the base metal at all. I'd like to see how they did that process.
That's been tig brazed with either silicone bronze or aluminium bronze using the cup walking method by someone who knew what they were doing. Very nice clean work.
have to agree with you , Coldman, I'd kind of lean toward the aluminum side with the color. VERY NICE.
cornmuse wrote:Before reading, I thought it looked like a reflux column for distilling booze!
The electric panel in the pic is just there to convince you it's radio related. You make a good point though, nobody would put that much effort into building a radio transmitter, but for booze? No bridge is too far!
I recon it might be done with a couple of filler rods, laywire together, keeping the low amp arc walking on the rods only and allowing the melted filler to wash onto the pipe and flange. Thereby minimising zinc gas out from the flange (although you can still see a black line at the toe) and tarnishing of the copper. I have some scrap brass and copper tube, I might try to replicate it. Going to the out back (past the black stump) on a couple jobs from monday for a couple weeks, I'll have a go when I get back.
I have built stubs before but always used the field flange kits which are silver soldered to the tube. Not a tig welder yet - finally have a machine, but have just started trying to learn it.
Call ERI or Jampro & ask one of the engineers - I'll bet they would share the process.
