Solder wick or braid
03 August 2011
Desoldering is the removal of solder and components for troubleshooting, for repair purposes, component replacement, or to salvage components
Desoldering is the removal of solder and components for troubleshooting, for repair purposes, component replacement, or to salvage components.
Solder wick or desolder braid is supplied in two forms; tin-plated or plain copper woven braid which is impregnated with flux.
The flux coating helps provide a protection to the copper braid during storage and helps wet the braid during soldering.
It is often seen in production that braid held in an operator's toolbox does not have the same wicking or capillary action during de-soldering. This is due to its age, so don't lock it away; use it in strict rotation like any other material.
Copper is the preferred braid as it is far easier to see the soldering, or rather, de-soldering action taking place. The solder can be seen to wick up into the braid away from the surface being de-soldered. It also provides a simple gauge to the solderability or age of the braid being used.
The braid works well for lead-free rework providing it remains solderable. Some companies that use braid in production also use extra flux. This is a very poor practice because if they used the braid from a good supplier and used when it when it was new then this would not be necessary.
Solder wick is also available in different braid widths and different copper weights. For surface mount, the wick size is smaller than it is for through hole work due to the reduced size of the solder to be removed. Care needs to be taken to select the right size, but a simple guide is that the wick should be equal to or slightly less than the size of the joint to be reworked.
Solder braid is used in two main applications during surface mount assembly for the removal of solder from surface mount pads after component removal. It is also used for solder short removal on SOIC or on fine pitch components.
However, it may also be used on conventional through hole boards for short removal and on single-sided non-plated through hole boards for de-soldering terminations, but heated vacuum de-soldering systems are the preferred method for plated through holes.
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