08-07-2011, 08:29 PM
I've brought this thread and its companion thread "The Solder Shop Q&A" over from the old Gauge's Academy. Both are threads originally by Randy Cline (rcline over there) with the Solder Shop being solely his work, while the Q&A section is by both him and other responders.
The Solder Shop
Welcome to “The Solder Shop”.
The idea of the solder shop is to “lightly” cover several different areas of the soldering field.
What is solder and rosin. How the two work together. and to give you a new out look on soldering.
So let’s get started!
Solder is an alloy composed of two different metals, which are Tin and lead. The melting point of lead is 621 degrees F. While the melting point of tin is at 450 degrees F. When the two alloys are mixed together to form solder, it now has a melting point of 361 degrees F. The alloy Solder is identified by its tin / lead percentage weight ratios. The tin content is always listed first, as in this ratio figure. Sn 60/40 ( Sn – the symbol for tin and 60 for representing 60% by weight, therefore 40 represents 40% lead by weight ratio).
All solder starts to melt at 361 degrees F. and all solder, ( except Sn 63/37 ) goes through 3 different states. First is the solid, then at 361 degrees it starts to melt and goes into what is called the plastics or putty range, and after it heats up a little more, then it becomes a liquid. Sn 60/40 becomes a liquid at 370 degrees F. Upon cooling down the process is reversed. It goes from a liquid to a putty and then to a solid.
Sn 63/37 starts to melt at 361 degrees F. and then at 361.5 degrees F. it is a liquid. Sn 63/37 is what we call Eutectic solder. It has no plastics or putty range. ( This is the only solder that I use because I don’t have to be as careful while holding my soldered connections in place while I’m waiting for the solder to cool down).
Principals of Soldering:
1. Soldering is in a group of welding processes which produce a joining of material by heating them to a suitable temperature and using a filler material having a liquidus ( melting temperature ) of “less” than 800 degrees F. The filler material is distributed between the closely fitted surfaces by capillary action and wetting. When molten solder leaves a continuous, permanent film and an intermetallic zone on a base metal, (meaning, when the molecules of the solder melt into and mix with the molecules of the base metal ) it is said to wet the surface. Without wetting there can be no soldering (welding) action. In order for wetting to occur there must be a surface mixing of the solder atoms and the base metal atoms. This surface mixing yields the intermetallic zone. The intermetallic zone is a new alloy composed of the solder metals plus the base metals.
2. Intermetallic reactions usually take place at the interface between the base metal and the solder. This reaction is partly chemical in nature. The liquid solder works as a solvent on the base metal, somewhat like water on a salt block. Small amounts of the base metal are dissolved and mix with the solder, while some of the solder soaks into the base metal and mixes with its molecules. Since the wetting process has mixed the base metal with the solder, a new alloy has been formed. If the base metal is copper, then the resultant alloy (intermetallic zone) is one of lead, tin and copper, having physical characteristics different from the solder or the copper.
3. Since heat is applied to facilitate the wetting process, care must be taken to avoid to much heat or an excessive amount of time that the heat is applied. Excessive intermetallic reactions may cause brittleness in the joint being soldered.
4. Wetting is a liquid actually touching or adhering to a solid surface. Wetting is facilitated by the ability of solder to alloy with the base metal. For example, pure lead does not readily wet to copper or steel, where as solder readily wets both. Some other metals increase the wetting properties even farther.
5. The forces of capillary action and interfacial tension assist solder to wet and spread along a base metal. Capillary action is the force of adhesion between a solid and a liquid. The capillary action in soldering is the drawing of a liquid between closely spaced solids, a consequence of surface tension, cohesion and adhesion.
6. Cohesion is the molecular attraction by which the particles of a body are united throughout the mass and Adhesion is the molecular attraction exerted between the surfaces of the bodies in contact.
The Solder Shop
Welcome to “The Solder Shop”.
The idea of the solder shop is to “lightly” cover several different areas of the soldering field.
What is solder and rosin. How the two work together. and to give you a new out look on soldering.
So let’s get started!
Solder is an alloy composed of two different metals, which are Tin and lead. The melting point of lead is 621 degrees F. While the melting point of tin is at 450 degrees F. When the two alloys are mixed together to form solder, it now has a melting point of 361 degrees F. The alloy Solder is identified by its tin / lead percentage weight ratios. The tin content is always listed first, as in this ratio figure. Sn 60/40 ( Sn – the symbol for tin and 60 for representing 60% by weight, therefore 40 represents 40% lead by weight ratio).
All solder starts to melt at 361 degrees F. and all solder, ( except Sn 63/37 ) goes through 3 different states. First is the solid, then at 361 degrees it starts to melt and goes into what is called the plastics or putty range, and after it heats up a little more, then it becomes a liquid. Sn 60/40 becomes a liquid at 370 degrees F. Upon cooling down the process is reversed. It goes from a liquid to a putty and then to a solid.
Sn 63/37 starts to melt at 361 degrees F. and then at 361.5 degrees F. it is a liquid. Sn 63/37 is what we call Eutectic solder. It has no plastics or putty range. ( This is the only solder that I use because I don’t have to be as careful while holding my soldered connections in place while I’m waiting for the solder to cool down).
Principals of Soldering:
1. Soldering is in a group of welding processes which produce a joining of material by heating them to a suitable temperature and using a filler material having a liquidus ( melting temperature ) of “less” than 800 degrees F. The filler material is distributed between the closely fitted surfaces by capillary action and wetting. When molten solder leaves a continuous, permanent film and an intermetallic zone on a base metal, (meaning, when the molecules of the solder melt into and mix with the molecules of the base metal ) it is said to wet the surface. Without wetting there can be no soldering (welding) action. In order for wetting to occur there must be a surface mixing of the solder atoms and the base metal atoms. This surface mixing yields the intermetallic zone. The intermetallic zone is a new alloy composed of the solder metals plus the base metals.
2. Intermetallic reactions usually take place at the interface between the base metal and the solder. This reaction is partly chemical in nature. The liquid solder works as a solvent on the base metal, somewhat like water on a salt block. Small amounts of the base metal are dissolved and mix with the solder, while some of the solder soaks into the base metal and mixes with its molecules. Since the wetting process has mixed the base metal with the solder, a new alloy has been formed. If the base metal is copper, then the resultant alloy (intermetallic zone) is one of lead, tin and copper, having physical characteristics different from the solder or the copper.
3. Since heat is applied to facilitate the wetting process, care must be taken to avoid to much heat or an excessive amount of time that the heat is applied. Excessive intermetallic reactions may cause brittleness in the joint being soldered.
4. Wetting is a liquid actually touching or adhering to a solid surface. Wetting is facilitated by the ability of solder to alloy with the base metal. For example, pure lead does not readily wet to copper or steel, where as solder readily wets both. Some other metals increase the wetting properties even farther.
5. The forces of capillary action and interfacial tension assist solder to wet and spread along a base metal. Capillary action is the force of adhesion between a solid and a liquid. The capillary action in soldering is the drawing of a liquid between closely spaced solids, a consequence of surface tension, cohesion and adhesion.
6. Cohesion is the molecular attraction by which the particles of a body are united throughout the mass and Adhesion is the molecular attraction exerted between the surfaces of the bodies in contact.