Anyone for Brazing?

[Nightjar]

On 23/04/2014 21:03, Andrew Mawson wrote: ...

That, to me, is the difference between brazing and hard soldering or silver soldering. The latter don't contain brass and have a white colour, which makes them more cosmetically suitable for some jobs.

I think mine must have been helping my father to make the wire mesh fronts to budgie breeding cages, using wire he had 'found' at work. That was with a 4oz copper bit soldering iron heated on the gas stove and probably around the same age.

Colin Bignell

[Stephen]

Incidentally most plumbers solder now is lead free (to prevent water being contaminated by lead and people ingesting it....)

This is 96S silver solder which is 96% tin and 4% silver.... so following your so called definition, its not "soldering" as theres no lead and and so plumbers are now "silver soldering" copper tube?

Additionally copper tube is malleable (otherwise it would not bend with a pipe bender/spring). yet you can buy half hard copper tube and this stuff can be bent......

silver soldering is not a hard solder, you can use emery paper on it easily.

[Nightjar]

or for Huge :-)

Colin Bignell

[Andrew Mawson]

Oh yes we know :( no pasty state for making wiped joints and it fails by crystalisation if vibrated - dreadful stuff.

Now where does emery sit on Moh's hardness scale ? 7-9 if my memory (as a non materials scientist) serves, and diamond is 10 so pretty hard isn't it !!!!!!!

Andrew

[Nightjar]

A very low probability that only is relevant in some areas. I grew up in a house with lead pipes and a nice hard layer of deposits on the inside, which isolated the lead from the water.

Not mine, Andrew's.

That was rather the point I was making about the soft solder we used for medical devices.

I hope that, at some point, you will grasp the fact that the hardness of the solder is not what defines hard soldering. It is simply a widely accepted alternative name for brazing or for silver soldering. As I said, I believe it derives from it being a technique for joining hard metals and that is also a loose definition, which does not actually need them to be hard.

Colin Bignell

[Nightjar]

Do I detect a certain amount of cynicism about modern job titles?

Colin Bignell

[F Murtz]

AS far as I know mapp gas is not made any more, the new stuff is mapp plus or some such thing and is slightly different.

[Stephen]

"pasty solders" are non-eutectic solders. They do not have a distinct melting point as such but have whats called solidus and liquidus temperatures. The pasty range sits between the solidus temperature and the liquidus temperature.

Solders that have no "pasty" aspect to them have a very distinct melting point and are called eutectic solders.

Another one to watch with lead-free solders is Tin Pest (which involves allotropy) and Tin Whiskers....... I'll leave that for another day!

[PeterC]

Now we know the real reason why tin-lead was banned for water - it was panic over the pasty tax.

[PeterC]

Only in Dalmatia.

[Andrew Mawson]

Oh yes ! It started when Dustmen became 'Cleansing Operatives' then arty farty types get together for 'workshops' and countless other examples of avoiding calling a spade a spade :) :) :)

Andrew

[Andrew Mawson]

Yes we actually know this, but are using terms others can be familiar with.

I echo Collins comments about lead pipes. Lead oxide, as you will undoubtedly know as a Materials Technologist, in pretty well insoluble in water. Lead nitrate and lead acetate are the only two salts of lead that are soluble, so you need a particular type of water containing other trace elements to cause a problem.

Like Colin I was brought up in a house, as were most people a few years back, that was supplied with water through lead pipes. Though I accept you could advance the argument that I'm as I am 'cos of this :)

Andrew

[Rick Hughes]

I used to get told off by Welding Instructors ... and told the correct term is bronze welding

[John Rumm]

Here in the south east (hard water) lead was pretty much a non issue. Any pipe you cut open had nice orange or yellow oxide coating on the inside so that the water never contacted the lead!

[mike]

Told off! Good grief, they needed something to do. Nothing wrong with "brazing", like 99% of the diy world would understand it anyway. (No I havn't done a survey) :-)

[newshound]

Yes, brazing is a universally understood generic term. But it also happens to be a specific process too, one which has been completely superseded by silver soldering.

[tony sayer]

In article , Andrew Mawson scribeth thus

Noo!,

Thats an "Earth inverting horticultural implement" !

And what's wrong with calling my missus the,

... "Comestible procurement executive" ...

[tony sayer]

Shouldn't that really have "Ferric" in it somewhere;?...

Close to an MF TX then as mine didn't;(..

[Nightjar]

On 24/04/2014 21:38, tony sayer wrote: ...

Not if you are welding aluminium, or titanium or plastic.

To follow the theme of this thread, we could also mention friction welding, which is actually a type of forging.

Colin Bignell

[Andrew Mawson]

No, virtually all metals can be welded. Aluminium is very commonly. Lead can be welded, but the accepted term is 'lead burning' despite the fact you try to avoid it oxidising! Disimilar metals can, and are commonly welded, the wires of a thermocouple being a common example. (Though no filler is used usually).

I actually managed to spot weld brass mesh to galvanised sheet in a recent project, and it was surprisingly successful.

Andrew