Technically speaking, welding can be divided into three broad categories:

Fusion welding. The joining of two or more metals by melting (fusing) them together, eg, welding steel with an alloy such as Magna 31.

Brazing. The joining of two or more metals with a welding alloy that has a lower melting than any of the base metals, but has, itself, a melting point over 537°C.

Soldering. The joining of two or more metals using a welding alloy with a melting point below 537°C.

Soldering is probably the most widely used of all methods of joining metals. However, soldering is also probably the least understood of all metal joining methods.

Soldering is used for two main types of application: production joining and maintenance joining. In production, soldering such items as automobile radiators, electronic and electrical equipment, are usually the result of a mass soldering installation machine which is complicated and programmed by a specialist consulting engineer.

Once the initial adjustments have been made, the operation becomes a simple metronome assembly without the need for human assistance. All or most of the variables are controlled. Production soldering is an automated system based on ideal conditions, clean metals, preplanned joint design and no human error factors.

Industrial maintenance soldering is entirely different from production Soldering can play an important part in industrial maintenance such as electrical circuits, plumbing, tubing, vehicles, sheet metal, wiring and a myriad of applications.

There are many different applications where Magna Maintenance Soldering is the ONLY answer and the RIGHT answer. For example, in a milk factory. There are times when dismantling or enjoining parts is essential to the efficiency of the operation. The stainless steel piping can be joined with Magna 88C. The result is a sanitary, leak-proof strong joint. However, the time comes when the cleaning operation must be done and, the only way to do this is to take the piping apart and - clean it. This can be easily achieved by a minimal amount of heat to dismantle the piping. The piping is cleaned and then once again joined back together with Magna 88C.

This could not be done, either by brazing or welding. Nor could the machine be transported back to the manufacturers for dismantling and repair. This, however, is only an isolated example of the thousands of situation-saving applications for the Magna Maintenance Soldering Process.

The repair of the aluminium guttering on a roof is a classic example. Ordinary production solders just cannot cope with a situation like this. Gas or arc welding would distort the metal. Magna 51 can join the aluminium gutter, giving it strength and rigidity and making it leakproof.

Another example is auto body repairs where Magna 81 fills in dents. It is far superior to ordinary solders or plastic fillers because it is vibration proof, peel proof and easily applied at very low heat.

Still another example is soldering cast iron, (once thought to be impossible) which is easily accomplished with Magna 79. It can join a cast iron intake nipple to a copper radiator or seal cracks in cast iron housings at such a low temperature that dismantling is not necessary.

There are endless numbers of applications where Magna Maintenance Solders salvage equipment that might otherwise have had to be scrapped. Instrumentation components, galvanized sheet metal, plumbing connections, water piping, sheet metal machine guards, electrical apparatus and numerous other applications that occur in every factory, farm, mine or industry can benefit from the use of Magna Maintenance Soldering Alloys.

Magna Solders are better for maintenance applications than ordinary solders for the following reasons:

(1) The Magna vacuum-melted method of solder production

Magna Solder Alloys are made by an exclusive proprietary vacuum- melting process. Ordinary solders are not manufactured with vacuum melting but are melted in the open air. The Magna vacuum melting process provides the following major advantages:

Ordinary solders are made from low-cost scrap tin and lead. The fact that the results from these solders are limited seems to have little or no distraction to its sale for the simple reason that few industries realize just what goes into a solder.

The impurities in ordinary solders cause serious and repetitive problems in nearly every field of soldering. The impurities include such metals as copper (which lowers the over-all resistivity); zinc (which will not go into solution but remains crystalline and gritty); bismuth (which has the ability to change the microstructure); aluminium (another that will not go into solution) and finally cadmium (which lowers the spread-rate).

Magna uses only virgin metals rated at 99.99% purity. These are melted in a vacuum and homogenized ultrasonically. Resistivity tests are then made on a double-Kelvin bridge using the four-pronged method.

Magna Solders are made from exceptionally high grade tin ore, which is crushed and concentrated by the floatation process. Impurities such as arsenic and sulphur are completely removed by an oxidizing roast and a dilute acid bleach. Other impurities such as lead, bismuth and antimony are removed by choloridizing roast and acid bleaches.

The ore is then purified once again in a reverberatory furnace which has been charged with concentrated tinstone, and mixed with metallurgical grade coal. The tin at this stage is approximately 99.50% pure.

However, in the Magna process, the purity factor does not stop there. The tin is refined by four additional processes to bring it to the highest level of purity available in any commercial solder today.

Sub formulations: The perfect solders are those that can be applied at the lowest temperatures. However, soldering temperature is the combination of 2 factors: Time and degree of heat. For example, a solder that requires 190°C and remains molten or liquid for 3 minutes, requires substantially more heat energy than a solder that requires 210°C to melt but which solidifies in five seconds.Molten solder reacts with metals such as copper - and formed on the copper surface, is a chemically distinct, intermetallic compound phase. And, most important, as long as the solder remains MOLTEN, the reaction forming this intermetallic compound continues. This compound (chemically CN6 SN6) is extremely hard and brittle. It is quite easily broken in shock by tearing forces.

Thick intermetallic alloys are weaker than thin layers. The obvious answer then is to reduce the soldering time. The less time the solder is molten and the faster it solidifies, the stronger and less brittle the bond.

The Magna Solder Alloy range achieves this rapid-solidification process admirably. Thus, the Magna Solders provide the optimum strength. However, let's take a look at production again. The normal solder used is the 40/60 tin and lead solder. Melting point is 237°C) and the solidification point is 182°C). A solder of this nature is apt to produce a joint of low physical properties because the solder is liquidated by heat over 55°C (the difference between the melting and solidification points). By contrast, Magna 87EC melts at 184°C and solidifies at 180°C with a plastic range of approximately 2°C. Magna 88C has no plastic range at all!

Unique self-annealing quality

The entire complement of the Magna Solder range is designed to self-anneal naturally, at room temperature. In maintenance the facilities are usually not available for annealing.

Flux cores

Many of today's solders are manufactured with an inner core of flux. The reason is, of course, to supply the solder surrounding it with the correct amount of anchor material at the correct time during soldering. The flux must act as the anchor to the metal for the solder alloy. It must clean the metal surface, penetrate it, de-corrode it and have a perfect affinity with the solder, and work piece, simultaneously. Only then can the bond take equal root between the two sections being joined.

An example of this fact is Magna 87EC. The flux core is not a simple water white resin as is common to the ordinary solder family; the special Magna 87EC Flux consists of Sylvic acid which is a heteroannulas diene.

At a given, preplanned temperature, the sylvic acid rearranges itself into a neoabietic acid. It also contains a by-product of pimatic acid which is a homannular diene. It is easily isomerized to abutic acid. Also, a different form of acid (also pimatic) is also used in the Magna 87EC Flux Core. This is a non conjugal diene which is stable to acid.

Several activators are added to promote energy when heated. The residue of the Magna 87EC Flux Core is a hard, transparent film of excellent electrical insulation. It will not absorb water. Then, as slightly more heat is applied, it undergoes disproportionation to a pyroabietic acid mixture, both of which are chemically inert. Thus, it begins its function as a strong acid that has powerful cleaning capacity...and ends as a virtually non-corrosive residue.

It is a fact that a properly made Magna solder joint between two pieces of steel has the full tensile strength of the steel itself. The only problem is fear itself - maintenance engineers do not trust soldered joints - because their only experience has been with ordinary production type solders which often do fail. Once they realize that there is a vast difference between Magna Maintenance Solder Alloys and ordinary solders, they will have the confidence to perform repairs at low heat they would never have attempted before.