1. What is Soldering?

There is a large difference between welding and soldering, and a fairly big difference of brazing.
WELDING is joining materials by melting similar materials at about the melting temperature of the materials being welded. So welding can be done with just heat, or another method of liquifying the materials to be joined.
SOLDERING is a process of joining materials by bonding a different material to both metals that are to be joined. The "different material" will have a melting temperature much lower than the melting point of the materials being joined.
Brazing is similar to welding except that the joining material is an alloy including copper, which melts at a temperature much higher than solder melts at, but lower than the melting point of the metals being brazed.

 

RE: Ian0 : <<lack of separate words in other languages for "solder" "weld" and "braze">>
Luckily in my native Latvian exist full set of words - lodēt (to solder), metināt (to weld), cietlodēt (to braze).

 

MrBill:""Brazing is similar to welding except that the joining material is an alloy including copper""
Not absolute always. teoretically, may braze with any metal having at least few centigrades lower melting point as materials to braze, and wetting it - the least under flux. Examples: Some sorts of copperless silver, the Hobart braze metal (https://datasheets.globalspec.com/d...3808-026/5f30a7bd-280a-41be-9b6d-5bd4f46f8ea2) and Ogle metal (https://books.google.lv/books?id=PY...CBkQAw#v=onepage&q=copperless brazing&f=false).
However indeed the absolute most of brazing metals contain the copper at least some 20% or much more.

 

MrBill:""Brazing is similar to welding except that the joining material is an alloy including copper""
Not absolute always. teoretically, may braze with any metal having at least few centigrades lower melting point as materials to braze, and wetting it - the least under flux. Examples: Some sorts of copperless silver, the Hobart braze metal (https://datasheets.globalspec.com/d...3808-026/5f30a7bd-280a-41be-9b6d-5bd4f46f8ea2) and Ogle metal (https://books.google.lv/books?id=PYZeHOZVeoYC&pg=PA718&lpg=PA718&dq=copperless+brazing&source=bl&ots=Akno692AYJ&sig=ACfU3U0Zg6HusVvOmu736KIlxonXAXvFVg&hl=lv&sa=X&ved=2ahUKEwjoiZqb1u2AAxWSavEDHfTgAQY4ChDoAXoECBkQAw#v=onepage&q=copperless brazing&f=false).
However indeed the absolute most of brazing metals contain the copper at least some 20% or much more.

Thanks for mentioning the WETTING part of soldering and brazing. That is the vital part of the process, the bonding of the two different materials, in both brazing and soldering.
I had not considered that some languages may lack adequate vocabulary, my experience has been that folks just have no understanding of even the results of the different processes.

 

Thanks for mentioning the WETTING part of soldering and brazing. That is the vital part of the process, the bonding of the two different materials, in both brazing and soldering.
I had not considered that some languages may lack adequate vocabulary, my experience has been that folks just have no understanding of even the results of the different processes.

I find that quite fascinating. I typed “solder” and “weld” into Google translate with the output set to Chinese. I can’t read the output, but it looked identical In each case.
French has “souder” for both “solder” and “weld”, and ”braser” which can mean “solder” or “brase”
German has “schweißen” for “weld” and “löten” for both “solder” and “braze”.
Perhaps someone who speaks Hindi, Arabic or Russian can contribute here?

Another thought: if you join lead to lead using a lead filler, why is it still called “soldering”?

 

Another thought: if you join lead to lead using a lead filler, why is it still called “soldering”?

Convenience. I would guess it is called welding in some cases. Now if you used tin to solder two lead things together…

I wonder, though, if they do, in fact, use and alloy rather than pure lead to reduce the melting point.

 

Another thought: if you join lead to lead using a lead filler, why is it still called “soldering”?

What I used was a 'plumbers stick' which I believe was not pure lead. It was purchased as 'Plumbing Solder".

 

Joining lead to lead is very tricky indeed. Trying to mend a damaged toy gyroscope that had the whole wheel assembly cast from fairly pure lead, with a broken lattice portion towards the center, was a daunting effort. The problem is that the pure lead wants to melt and run away at very close to the solder melting and wetting temperature.
And the whole thing must have been an antique, because I can not imagine a toy with a lead part now being available anywhere.