| Best Brazing Practise |
| Silver Soldering Tips |
| Strength of Silver Solder Joints |
| Silver Solder |
| Silver Solder Fluxes |
| Soft Solder Fluxes |
| Flux Cleaning Salts |
| Boiler Fittings/Accessories |
| Cadmium Bearing Silver Solder |
| Cadmium Free Silver Solder & Fluxes Prices incl VAT & Delivery |
| Soft Solders Prices include VAT and delivery |
| Copper Phos Alloys |
| Silver Solders |
| Refrigeration |
| Small Pack Prices - include VAT and delivery |
| Sievert Propane Torches, Burners & Hearths. Prices include VAT & Delivery |
| Joining Aluminium |
| Joining Brass |
| Joining Cast Iron |
| Joining Stainless Steel |
| Joint Cleanliness |
| London Jan 2012 |
| Shepton Mallett 2011 |
| Harrogate May 2012 |
| Guildford Jul 2011 |
| Bristol Aug 2012 |
| Midlands Oct 2012 |
| Sandown 2010 |
| Society Presentations |
| References |
| What the professionals say |
Silver Solder Fluxes
"The silver solder melts - but it won't flow - it just goes into a ball and falls off"There is nothing wrong with the silver solder. You have a flux problem!
The flux to be used with any silver solder is decided by three considerations all of which must be satisfied. These are
a) the melting range of the silver solder
b) the parent materials.
c) the heating cycle
Silver Solder Flux
Generally speaking 99% of all silver solder joints can be successfully made using one of two basic flux types. They behave in exactly the same way as the solder. They flow into the joint gap by capillary action prior to the alloy melting removing the oxides and keeping the joint "clean" at temperature.
EF Flux
By far the most popular flux used with silver solder is this low melting point flux based on alkali floro-borates. It melts at approx 550 deg. C, has excellent cleansing and capillary flow characteristics (essential for successful brazing) and stays active for a reasonable length of time. The active life of EF "Easy Flowing Flux" is sufficient to cope with most silver soldering heating cycles. The flux residues are readily soluble in warm water perhaps with the help of a soft nylon brush.
Or use a bath of citric acid 20gms salts/litre of water
EF flux will enable joints to be made between the common parent materials. These are copper and its alloys, (eg brasses & bronzes), mild steel and cast iron. The exceptions involve prolonged heating or joining aluminium bronze containing more than 2% aluminium and stainless steel. These exceptions will be dealt with later.
HT5 Flux
HT5 contains metaborates that offers a longer life at higher temperatures than EF flux and is recommended for longer heating cycles. It is also more aggressive and is capable of removing the oxide of chromium and as such is suitable for stainless steel. Use with higher melting point silver solder or during protracted heating cycles.
The flux residues are more "glassy" and are more difficult to remove.
Use 10% caustic soda solution or elbow grease.
Both fluxes are available in 50 gm sachets, 250gm and 500gm containers.
Hint 1
Both these fluxes become fully molten and working at a temperature of about 560°C. This is an excellent guide to the joint temperature. Apply the silver solder only when the flux has melted. To do so beforehand leads to a tendency to heat the rod, it melts but the joint is cold and freezes the alloy. The result is a superficial joint with no penetration.
Hint 2
When mixing the powder into a paste add a few drops of detergent.
It helps make the powder into a smooth paste,
it helps the paste "stick" onto the parent materials.
and if the paste dries out a little (and it will!) it allows the paste to be reconstituted by simply adding a little more water.
Hint 3
Brazing Aluminium Bronze with up to 10% aluminium?
Add 20% by weight of table salt to the flux powder. The increase in chloride ions helps to remove the aluminium oxide.
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