Why Copper

cheap, conductive, malleable, solderable. probably others will add reasons, or change the order, heck aluminum's been used as conductors, but it corrodes far easier than copper.

Well... Gold and silver might be a bit better, but too expensive. You will occasionally see copper with gold, silver, or tin plating on it. Tin enhances solderability but by itself melts at too low a temperature.

Aluminum is a good conductor but not solderable. More importantly, aluminum forms an *invisible* nonconductive coating as it oxidizes in air. With copper, you can see the tarnishing happen, which is much better; you know whether it's clean or not.

Iron and steel are harder to solder than copper.

If you need to ask this question then I don't see a future for you in electronics. Have you ever thought of doing some basic research on the web, or even reading a few books from your library?

Is this forum only for questions that cannot be answered by library research? I've been using it sporadically for about a decade and never knew of that restriction.

If you don't want to answer a basic question, you don't have to.

will

Change that to solderable with difficulty. There are fluxes such as fluoride fluxes that will make soldering to aluminum easy. I soldered a piece of aluminum by sanding it and covering it with a layer of greasy flux to prevent it from oxidizing. Then with a soldering iron that puts out a lot of heat, the solder wets the aluminum like other metals.

If that were true, you could not test for conductivity with a DMM for example. The layer is so thin that it poses little barrier to electricity. As far as invisible, well, if the aluminum has been exposed to air then it is a given that it has the oxide layer.

know

With aluminum, it's a given that it has the oxide layer.

Again, it depends. On how thick the metal is, what lind of flux is used, and of course, the solder, etc. Remember that the usual soldering process is optimized for copper, so using it on a different metal may not give as good a result.

in

the

never knew

Yes, and if you don't like the question the luser asks, because it shows that he did absolutely no reading up on it using the Web, then you can rebuke the luser.

So there may not be a restriction, but you can certainly expect a rebuke from others.

and iron and steel are soldered all the time, in industry, in home shops, no big problem, but it's called brazing, cause brass is used as the solder i guess. the temps are quite high, so it's not really applicable to electronics, but i suppose industrial cabling could use it.

I ran into a problem where someone tried to fix a leak in t water cooled TV transmitter by braising the brass fittings to the 2" copper pipe. It was a real pain in the ass to salvage the brass fittings which were long out of production. I had to cut the pipe off flush, then carefully file away the braised areas before I could heat everything and pry out the copper stubs. The brass parts were used to split the water flow for different tubes and had been custom cast in the early '50s

Brazing is done with "hard" (silver) solder. It doesn't seem to have anything to do directly with brass- the other meaning of "braze" (decorate, make of, or make hard like brass) came from a different word (OE "braes") according to AH4.

BTW, "braising" is a cooking term- browning in fat, then simmering in a bit of liquid. The root (OF "brese") is thought to be the same for the two words.

Sounds like a real PITA to salvage the manifold. I imagine it would be easy to have small leaks if you were not very careful.

Best regards, Spehro Pefhany

soldering

may

shops,

solder

Brazing isn't soldering because it doesn't use solder.

Long ago I watched a guy putting in a cathodic protection system. they dug a 3 or 4 foot deep trench and drilled holes every so often along its length. The holes each had a carbon cylinder with a large copper condsuctor coming out of it. The trench had a heavy copper conductor along its length, and at each cylinder, the copper conductors had to be joined. So the guy had a firebrick mold that he clamped around the two conductors. He filled it with a thermite compound that had a lot of copper in it. When he lit it off, it burned like a very bright sparkler, and left a casting of copper or some alloy around the two conductors.

Sorry but my eyes are bothering me today so i just used the spell checker.

This was a high pressure system with 7000 volts DC on the water and they had used brass rod in their attempts to repair the plumbing. When I reassembled the cooling system I pre tinned the pipe and all the fittings, removed the flux and looked for any area that wasn't tinned before I soldered everything together with an acetylene torch and a small tip

i believe that even if it doesn't contain lead it can be called solder, far as i know it refers to any non-fusion weld involving metal as a glue. or are you refering to another reason it's not soldering?

solder,

glue.

Looks like the consensus is that brazing is higher temp than soldering.

Actually, 'brazing', did originally use brass, and still does for many processes. However the term was first stretched to cover brass alloy rods, that melted at lower temperatures than brass, and latter to include 'silver soldering'. Many of the so called 'silver solders', have very low silver contents indeed, and some have none (palladium alloy solders for example). In jewellery work, there are about five different 'grades' of 'silver solder', with the hottest (hard or 'enamel' grade - because the melting point is high enough to allow enamelling), while the lowest temperature versions have melting points only a little above the conventional tin/lead solders. The terms have 'spread', to the point where you have to be very careful. Normally, the so called 'silver solders', used in industry, still have a significant quantity of brass, so joints using these, are quite regularly referred to as 'brazed', or 'low temperature brazed', and many people now use 'brazing', generically to cover any form of hard soldering (including things like aluminium soldering...). The dividing lines now, are normally drawn at 450C, for 'soldering', 450 to 900C, for 'low temperature brazing', and 900C+, for 'high temperature brazing'. Have a look at:

Best Wishes

A common brand of this (so common that it's like "xerox" in use) is Cadweld. The company I work for buys them by the tens of thousands. Driving around in a truck or work train filled with thermite has known hazards... hard to put out a fire that doesn't need any oxygen to burn, and which happens to be melting its way through the truck bed/railcar!

Tim.

Do not think that soldering is like gluing. Solder attaches itself to base metal by dissolving some of it and forming an intermediate alloy layer. Ever notice how unplanted copper soldering iron tip gets eaten away?

i do believe i mentioned something about higher temperatures.

I beg to differ. The oxide presents a VERY BIG barrier to electricity. You can test for conductivity because the oxide is thin and your probe is pointy to puncture the oxide. mike