aluminum can melt easily and will do so without warning.

products that use a rod of material and torch might work where the pieces to be joined are large, in this case the pieces to be joined are the same size as the rod. even accounting for different melting temperatures when you get hot enough to melt the rod you would be hot enough to melt the wire.

aluminum oxidizes easily. welding methods prevent oxide formation. the product mentioned and soldering require aggressive wire brushing during the process to remove oxides. that may work on large items to be joined with flat areas. in this case where you have wires joined it would be near impossible to brush the curved wire surfaces adequately without bending your antenna all over the place and disrupting the joint.

in this case where you have wires joined it would be near impossible to brush the curved wire surfaces adequately without bending your antenna all over the place and disrupting the joint.
Good point. On the infomercials, they do only show how it works on relatively large aluminum pieces.

Does the 'skin effect' really only deal with the outside surface area? (Is that all we have to worry about for antennas?)

The reason I ask is because I found some 1/4" hollow-core copper tubing for sale at Home Depot, but wasn't sure if it was suitable for antenna use due to the fact it was hollow (and I think it would 'pinch' at any bend points, unless there's a way to bend it without it collapsing inwards, like a cheap telescopic antenna does when bent).

Most commercial vhf antennas and a lot of uhf antenna elements are tubing. With the low currents involved, I think skin effect predominates. For coax cable used with a preamp, a lot swear that solid copper RG6 works better than copper clad steel RG6. Part of that may be due to the quality of the coax, as copper clad steel RG6 is generally cheaper stuff.

With tubing, its harder to straighten, and not necessarily cheaper. The pinch point bulge could be hammered down.

Hollow tubes are often used for VHF and above use as the skin effect keeps the signal on the surface. Solid or hollow makes no difference. Hollow tubes will also greatly reduce weight.

To bend copper tubing of the sort you describe, there are devices that plumbers use-- it's a coiled steel spring that had an inside diameter that is just bigger than the tubing it's made to bend. you insert the tubing into the device, then bend whatever angle you need-- I don't know how small a bend you can get, but i think it should work down to about 2 1/2" dia. which should be sufficient for our purpose

johnpost,

I went to HD today to find a solder kit.

Eventually I would like to solder the #10 copper wire used as the antenna whisker to the #10 copper wire phase line. Generally, the whisker wire is placed over the phase line wire. This results in 2 very tiny contact points between the two wires.

The goal here would be to stabilize the connection, and maintain maximum conductivity. A brass bolt & nut would still be used in addition.

HD sells an electric solder kit (tip) for "microelectronics and electrical" works. It is rated as 220 deg. C (470 deg. F) max. heat. Also they have a rosin solder (for electrical works) which does not say it's composition.

Is this the correct equipment and material required?

In the same section they also sell the gas torch guns, which I think is overkill..???

Thanks.

Eventually I would like to solder the #10 copper wire used as the antenna whisker to the #10 copper wire phase line.

HD sells an electric solder kit (tip) for "microelectronics and electrical" works. It is rated as 220 deg. C (470 deg. F) max. heat. Also they have a rosin solder (for electrical works) which does not say it's composition.

Is this the correct equipment and material required?

In the same section they also sell the gas torch guns, which I think is overkill..???

Thanks.

an electronic soldering iron (5 to 35 W) will not solder two 10 AWG wires together. the joint will never get hot enough to melt solder. you need to apply heat faster than than it can flow away from the joint. a 200W soldering gun will work fine.

propane torches can have a solder tip that fits on the burner. if you buy in a kit you will often get that and a flame spreader and striker. takes one second to solder two 10 AWG wires.

unless you will do a lot of large electrical or artistic soldering (which would make the gun useful) the propane torch is probably more useful to the homeowner.

have a person (with pliers or gloves) hold the whisker to the phase line. or place the whisker and phase line on a block of wood (everything supported ) and solder.

i've fasten the phase lines to the antenna except at the joint to be soldered. i would put a thin piece of wood under that point (end of a wood shim, popsicle sticks), support the whisker at the right height and solder. after letting it cool i then fasten that point with the screw and move on to the next. so i use the antenna as the third hand for the phase line.

use electrical rosin core solder only (flux is in the solder). do not use plumbing solder or plumbing solder flux, which might be near the propane torches in the store.

Heh.. another forum member was over here the other night to look at the antenna setup, and I went to show him how brittle that T6 aluminium is.. except the scrap cutoff piece I chose then bent nicely without breaking!

Which means that, somewhere in my stock of 1/4" alum rod, is at least one bit of softer bendy aluminium. Dunno which one(s), though. :)
Well, as it turns out.. *all* of the 1/4" aluminium rod I have here seems to be soft enough to bend at 90 degree angles. It was only the very first sample from Metal Supermarket which I tried (months ago) that was too brittle to bend without breaking.

The 5/16" from Metal Supermarket does break, though.

johnpost,

I have attached a photo of my solder test, using plumber's torch and plumbers silver bearing solder.

http://s638.photobucket.com/albums/uu110/stanicet/?action=view&current=IMG_0290.jpg

Does this look relatively adequate to you....

Given we don't necessarily know the exact composition of say rosin core solder, how can we judge what the conductivity, corrosion, and oxidation behaviour will be ?

Given we don't necessarily know the exact composition of say rosin core solder
Its usually listed on the roll, ie 60% lead 40% tin, (or the newer stuff with more tin and a little bit of silver)

no, this one didn't say, it was with the electronic/electrical soldering stuff, and said it was for that work, weird? Guess I have to assume it's high conductivity, but not sure about mixing up the metals with the copper...

As long as you get the excess rosin off when finished, it holds up well outdoors.

johnpost,

I have attached a photo of my solder test, using plumber's torch and plumbers silver bearing solder.

Does this look relatively adequate to you....

Given we don't necessarily know the exact composition of say rosin core solder, how can we judge what the conductivity, corrosion, and oxidation behaviour will be ?

there are hundreds of solders. for electrical, plumbing and mechanical uses.

most plumbing solderers i've seen (i'm not a plumber) need external flux. i think that is because there is so much surface needing to be cleaned it needs a lot and has to be brushed on first.

modern electrical solders have rosin flux inside of the solder.

it does look to be wetted by the solder so that indicates that the joint was hot enough. you want to see the solder flow onto both wires, you want to add enough solder so that it makes a curve between the wires ( a fillet) and that it leaves a shiny (at least nondull) and nonpitted surface, look at it from all sides. from what i can see it doesn't look bad.

the copper should touch tightly and so conductivity should then be good. the solder stabilizes and protects the joint.

unless you used 10 times the amount of solder needed (and had excess solder dripping all over) then the rosin flux was probably used up in cleaning the metal surfaces and there is no excess. if you used way too much solder you might see brown show up in the surface, that is excess unused flux. with the right amount of solder there isn't concern with flux damage but you could give a wet rag wipe if you wanted.

as an aside for plumbing using acid flux always thoroughly wet wipe the outside and flush the inside with many gallons of hot water. that acid flux remainder if left on the pipes will shown up as that green copper oxide which will continue to rot the copper.

the copper should touch tightly and so conductivity should then be good. the solder stabilizes and protects the joint.

So this means it doesn't really matter if there is lead in the solder, which is less conductive, since no solder actually enters in between the 2 copper wire s?

So this means it doesn't really matter if there is lead in the solder, which is less conductive, since no solder actually enters in between the 2 copper wire s?

yes ideally in wire soldering, point to point, you should make a mechanically tight and conductive joint which the solder stabilizes and protects.

it this particular situation the wires are mechanically tight together temporarily before soldering and attached long term with a screw afterward. most situations will have the wires mechanically tight long term before soldering.

there are soldering applications where the solder is part of the conductive path.

the lead (or lead replacement metals where required) is there very importantly for its low melting point. the tin is there to mingle with the copper surface and its voids to create the bond. other metals can be added for various properties, like where the solder needs to be a significant conductor.

there are soldering applications where the solder is part of the conductive path.

why wouldn't this apply to our antenna work?

why wouldn't this apply to our antenna work?
Because you should have good copper to copper contact before soldering.

most plumbing solderers i've seen (i'm not a plumber) need external flux.
Radio Shack (I think they still sell it, it been a while since I bought some) sells rosin flux. I use a tiny bit of it on joints since there never seems to be enough of it inside some of my older rosin core solders. The small tube lasts a long long time since I use tiny amounts. (less to clean off)

why wouldn't this apply to our antenna work?

solder is a conductor. in some applications it is expected to be 100% of the conductor.

when joining twisted wires or a wire/component to a solder lug you want a mechanically tight joint with near zero resistance before soldering.

here you are laying two wires next to each other. if they are tight then heating one wire would heat both and solder would flow around the joint and there would be some amount of copper touching copper. if they aren't tight then both wires would need to be heated and some solder would flow into the space between the wires. both will be conductive though the copper/copper joint be more so.

it can be a challenge to hold 2 wires tight for this even with a helper. one method is to use the tip on only one wire and use that to press that wire into the other wire, this will give copper/ copper contact. if one wire is on top of the other you can press down which is easier, you have 2 wire thicknesses like in your photo. you can also have the wires side by side (a helper is good here to stabilize one wire) and use the tip to press one wire into the other one, this leaves one wire thickness.

you would have to make these joints and saw them apart to see if there was and how much copper/copper contact and if there was a solder bridge. in physically yanking apart wire solders of different kinds in the past it seems to leave copper/copper contact if the joint was tight and done with good technique.

it can be a challenge to hold 2 wires tight for this even with a helper. one method is to use the tip on only one wire and use that to press that wire into the other wire, this will give copper/ copper contact. if one wire is on top of the other you can press down which is easier, you have 2 wire thicknesses like in your photo.


yes, this made it much easier, but creates 2 levels, which in turn creates lop-sided when bolting down!

I actually use vice grips coming in on top of the joint while soldering and leaned them on a tin can - worked like a charm!

now I will probably get the RS 60/40 .8 mm rosin core solder or the 63/37...