silver soldering question

[chrispare]

OK this may not be the right spot for this but here goes,
I would like to know how hot does it take to come apart when silver soldered?
I would like to make a small tuned pipe for a internal combustion engine, the material will be quite thin so there will not be much pressure but there will be a fair amount of heat. Also how thin of material (tin) can be soldered without burning through.
Also is it hard to do?

chris

 

[picclock]

Hi Chris

Silver solders melt at different temperatures depending on composition. The one I use melts at 640C. I would think it will weaken a fair bit below that.

Hope this helps

picclock

 

[arnoldb]

Hi Chris.

Like Picclock said, silver solder (or more properly, and to prevent confusion, silver braze hard solder) comes in different melting ranges - all above 600 C. Once something is silver brazed hard soldered, it actually requires a higher temperature to re-melt a joint than was originally used to braze hard solder it.

Having said that, you will not be able to solder tin with silver braze hard solder, as the tin will melt long before things get to brazing temperature.

With care, very thin or small pieces can be silver brazed hard soldered, especially if you use "silver solder paste", but it does require a bit of skill with the torch to make sure you don't get things too hot.

As to hard to do, well, no. It needs just a little practice to see how things behave while brazing soldering to get a good feel for it.

Regards, Arnold

[Edited use of terminology]

 

[tel]

tsk tsk Arnold - Silver soldering is a different and distinct operation from brazing - a fact that was hammered well into us during the oxy/acet course all those years ago. Hard soldering - yes, brazing - no!

One of the tricks with hard soldering thin bits is to take your rod, put the end on a clean surface and with a clean hammer belt the bejabbers out of it. Now snip the flattened end to a point and you will be able to apply a tiny amount that won't require a hot of heat to flash.

That said, I don't think silver solder would stand up to your application, tho I am always willing to be proved wrong.

Definitions;

Soldering - The AWS defines soldering as a group of joining processes that produce coalescence of materials by heating them to the soldering temperature and by using a filler metal (solder) having a liquidus not exceeding 840ºF (450ºC), and below the solidus of the base metals.

Brazing - Brazing joins materials by heating them in the presence of a filler metal having a liquidus above 840ºF (450ºC) but below the solidus of the base metal.

 

[steamer]

Tel,

If my memory serves that is also the definitions for soldering and brazing in the machinery handbook....my brand new....uhummm.25 years ago : 23rd edition anyway.

However, these terms are often, and sometimes with forceful argument, used interchangably with silver over here.

Don't know really why...history probably....I just translate in my head to avoid the debate... ;D


Dave

 

[arnoldb]

I happily stand corrected, though it's a bit hard to type now; my fingers are smarting a bit

Kind regards, Arnold

 

[tel]

Sorry mate - din't mean to whack you that 'ard! ;D

 

[steamer]

Ahhh no wacking involved Mate.....I find it curious that an agreed upon written specification that seems to have been adopted by at least two continents....can become a point of contention....in any case

How ya doin Tel ;D


Dave

 

[tel]

Orrite mate, you?

 

[steamer]

I'm good.

 

[Blogwitch]

Tel,

I think where the problem lies is in fact the US lads.

A lot of them have difficulty differentiating between soft and hard solder and sometimes things get very confusing. So I think silver soldering (hard) is now being called silver braze and what they call silver soldering (plumbers style, which we call soft soldering) is staying as silver soldering, just in an attempt to make it easier for them to understand what is going on in other parts of the world.

As you say, braze is usually very hard (metal wise, not to do) joining method using a brassy type rod and flux, and is flowed like the softer solders, and then bronze welding which uses a hard brassy filler rod, as with braze, with a flux, but in a filling technique similar to gas and arc welding, where you are filling pre cut V's, especially useful when repairing cast iron and cast steel castings, where normal welding sometimes causes hardening problems.

As you can see, using the wrong word can get very confusing. I just wish things were a little more standardised and everyone knew which was what.


John

 

[steamer]

The argument I hear in the US is that silver brazing ( above 840F) is used interchangably with silver soldering....sometime with great vigor!

If I mention the specification....they just get more angry.....I leave it be.

Dave

 

[arnoldb]

;D - No worries Tel/Dave - I was raised by the book, though Swarfmaker never bothered to read it; a good whack with it used to sort me out and hurt a lot more back then :big:

Thanks John, exactly the point... - I don't know where Chris is from.

Lets rather use the can 'o worms and go fishing now - like Dave said

Kind regards, Arnold

 

[steamer]

Oh I like "fishing"... ;D

 

[Rivergypsy]

Have you thought about either rolling the sections from thin stainless and then passing them to a friendly TIG welder, or alternatively hydro-forming the pipe? Both have worked for me nicely in the past...

Dave