Focusedonsound wrote:
Teken,
If mindctrl doesn't I sure would. |
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Alright, not a problem. I will however not include some of the information that pertains to board level repairs, or that which applies to surface mounting techniques.
As it does not apply here directly. But the basic principles are still valid, and hold true.
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CLEANING:
There are (5) five things which the technician will observe for each stage of the preparation.
1. Cleaning all components, circuit boards, tools, and materials to be used for the soldering process, this includes the solder itself.
2. Selecting the flux.
3. Determining the heat to be used and the length of time to do the jo, which are based on thermal mass of the parts to be connected.
4. Selecting the solder.
5. Choosing the flux remover.
Cleaning the soldering iron tip: The soldering iron tip should be bright silver with no flux residue or solder on it. Any major buildup of oxide on the tip is removed by wiping the tip on a damp wet sponge. With the cleaning stroke in a form
X
The process of wiping the tip of the iron onto the sponge is called *Shocking*
The act of shocking the tip, steams off the oxides and leaves the tip clean and free of any contaminates.
*Anytime the iron is left to cool, or placed back into storage. Place a large lump of solder on to the tip of the iron. This will prevent corrosion, and protect it from external damage.*
FLUX: Prevents oxidation and removes the thin layer of oxide and the atmosphere gas layer from the area to be soldered.
When the flux is applied to the area, it permits the solder to flow, or wet, smoothly and evenly over the surface of the lead or wire being soldered.
Flux also promotes the flow of heat, resulting in a faster heating of the items or areas being bonded.
There several types of flux on the market, some can be used on board levle electronics, and some cannot.
The following are the most common types of flux and I will indicate which ones cannot be used on the board level.
Acid or zinc based fluz should NEVER be used on the board level repair. It is also known as RA flux.
The acceptable forms of flux are pure roslin flux, and mildly activated roslin. Which is also known as R or RMA flux.
There are also flux that is made from lemons, which makes it very easy to clean, but must be thoroughly cleaned, if applied.
WETTING: If the correct flux is used and applied it will greatly assist in all aspects of the soldering and desoldering process.
What it does is improve the intermetallic bonding and solder flow.
HEAT - TIME - MASS
The heat to be used, time on a connection, and the mass of the joint. Because not all connections are the same, consideration must be given to the differences in the mass of the joint and adjusting the heat and time accordingly.
In terms of heat, the hotter the iron the faster the rate of oxidation. So it does not benefit anyone to use a iron that is 800'C unless the high heat solder is being applied.
The standard iron is 25-30 watts, which is more than reasonable for automotive use.
To give you an idea of oxidation and the rate of it, for a given heat range they are listed below.
600'F <-- Standard iron, oxidation forms on the tip of an soldering iron, uncoated with solder.
700'F <-- Is 10 times more oxidation.
800'F <-- Is 100 times more oxidation.
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I will write out the rest later, I am tired.