9
Tips and Techniques
The following is a list of the common solder alloys and their respective melt
points. This can be used as a guide to choosing the appropriate SET point for your
application. Keep in mind that many variables factor into the optimal set point
and you may have to experiment to get the best results. One of the important
considerations, if you are salvaging usable parts, is to have the temperature of the
tip high enough so that you can quickly heat the joint and evacuate the solder
before heat can travel up the lead and damage the component.
Alloy Melt Ranges
LEAD-FREE
215 C to 245 C
TIN-LEAD
Sn60/Pb40 through Sn30/Pb70 185 C to 258 C
Sn05/Pb95
301 C to 320 C
TIN-LEAD-SILVER
180 C to 300 C
Effective Desoldering Technique
Choose a solder tip hole size that is appropriate for the size of the solder pads
that you will be cleaning. See the “Maintenance of the ZD-985” section for the
proper tip changing procedure. Use enough tip heat so that you can place the tip
over the target solder joint and within a second or two push the trigger of the
gun. Continue to hold the trigger as you pull the gun from the solder joint. This
allows air to enter the tip and sweep the residual solder into the solder capture
container. Once you are clear of the joint you can release the trigger. If the board
has traces on multiple levels or if the traces are very wide it may be necessary to
leave the Desoldering tip on the pad longer to allow complete solder melting to
occur before pulling the trigger. Sometimes it is also necessary to move the tip
laterally on the pad so as to reposition the wire slightly so all the solder can be
vacuumed from the pad.
