Silver solder ?

[PackmuleParticipant @packmule]

Is there any particular reason why parts are silver soldered instead of normal brazing?

[PackmuleParticipant @packmule]

[Michael GilliganParticipant @michaelgilligan61133]

Silver Solder is available in a range of melting points; all lower than "normal" Brazing temperature.

It is adaptable to very fine work.

It flows very well, and makes neat joints.

< etc >

MichaelG.

.

Some useful notes here

Edited By Michael Gilligan on 08/07/2013 10:39:14

[peter walton 1Participant @peterwalton1]

The use of brazing rod on boilers is a no no as it will dezincify over time and could blow up!

I suppose you could use a bronze brazing rod!

Peter

[PackmuleParticipant @packmule]

Thanks Guys,

knew there must be a reason , dont know ? ask

Cheers Bob

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Silver solder :

Melts more easily than brazing rod so relatively large jobs can be done easily with modest equipment . Also the lower melting temperature means that damage to typical copper boiler parts and brass / gunmetal assemblies is unlikely .

Flows readily right through flanged joints et al whereas brazing rod tends to sit on the outer edges unless great care is taken and very adequate heat is available .

Chemically is relatively inert so doesn't corrode away too rapidly in presence of combustion products or acidic water .

Requires a simple relatively harmless flux in most cases .

Will remelt relatively easily without too much deterioration of composition .

Brazing :

With adequate heating brazing is good for many ' garage ' type jobs of fixing things together and is relatively cheap .

Historically was the only thing available for engineering work and a lot of early steam engine pipework was done with brazing . Reached a very fine art in manufacture of brewing equipment and stills .

MikeW

 

 

 

 

Edited By MICHAEL WILLIAMS on 08/07/2013 13:51:18

[peter walton 1Participant @peterwalton1]

Just been in the garage and noticed my pack of 'Sil-Phos' brazing rod, ok for car or gap filling jobs not sure it is of any use for boilers etc but the bees knees on the body work!

peter

[Keith HaleParticipant @keithhale68713]

Why silver solder? Please bear with me !

There are several types of brazing alloy.

nickel brazing alloys – marine

gold brazing alloys – jet engines

palladium brazing alloys – jet engines

copper brazing alloys (includes brass and copper-phosphorus alloys eg silfos)

silver brazing alloys (silver solders)

Brazing defines the metal joining process not the alloy

Copper alloys are the cheapest and very versatile. So there has to be a very good reason to move away from them . That is invariably due to a technical reason. These include melting temperature, parent material combination, corrosion resistance, even colour or a combination.

The success of the process depends on correct joint design, heating technique and fluxing. If these criteria are not met no brazing alloy will work.

Peter, a word of caution. Silfos contains phosphorus. It appears to work well but combines with iron (in all steels) and nickel to create a very brittle intermetallic compound that can lead to catastrophic joint failure when stressed.

Copper phosphorus brazing alloys used to join copper nickel pipes on a submarine is thought to be the reason a submarine did not return from its' test dive.

keith

[Keith HaleParticipant @keithhale68713]

The decision to use brazing as the metal joining process in preference to soldering or welding is based on technical reasons eg parent material combination, temperatures, strength, corrosion resistance.

Brazing defines the process not the alloy used.

There are several sorts of brazing alloy.

Nickel brazing alloys – marine, nuclear applications

gold and palladium brazing alloys – jet engines

copper brazing alloys (eg brass and silfos)

silver brazing alloys

If the basic principles of the process – correct joint design, heating technique and fluxing – are not followed no brazing alloy will not work satisfactorily.

Peter a word of caution re silfos.

It contains phosphorus which will produce very brittle joints on steel and nickel bearing materials. Such a material is thought to be the reason a submarine did not return from its' test dive

Phosphorus does not like hot sulphur containing atmospheres eg boilers. your technical reason for using a silver brazing alloy (silver solder!)

[CuP AlloysParticipant @cupalloys]

Hi there.

Brazing is a means of joining metal, as applies similarly to soldering and welding. It defines the process not the filler metal.

The decision to braze and the alloy used is decided by technical reasons eg temperatures involved, parent metal combination, strength, corrosion resistance, even colour.

If the basic principles of joint design, heating technique and fluxing are not followed, no brazing alloy will work satisfactorily.

There are several forms of brazing alloys.

Nickel brazing alloys – nuclear and marine applications

Gold and palladium brazing alloys – jet engines

copper brazing alloys (brass and copper phosphorus alloys eg silfos)

silver brazing alloys (silver solder)

The success of all depends on the same principles.

Peter – a word of caution re phosphorus containg alloys. They produce very brittle joints on parent materials containing iron or nickel. Such a material was used to braze copper nickel pipes on an american submarine. It did not return from its test dive.

Phosphorus bearing alloys corrode very quickly in hot sulphur containing atmospheres eg coal fire boilers. One of your technical reasons for using silver brazing alloy (silver solder!)

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