Probable Causes of
Soldering Iron Tip Failure
There are many factors that
influence soldering iron and tip life. Tips life will depend on proper
maintenance, cleaning, temperature, tip configuration, and the jobs being done.
Get the best performance from your iron and maximize tip life by following these
simple suggestions and precautions. For soldering iron and tip care suggestions
go to tipcare.htm.
- Make sure you have the correct amount of voltage in your line for your
iron. Most irons are designed to handle slightly varying supply voltages but
a consistently high line voltage will cause the iron to run hot and reduce
tip life.
- The higher the tip temperature, the faster oxidation forms. Soldering at
temperatures over 875º F causes your iron tip to oxidize twice as fast as
soldering at 700º F. Adjust your soldering temperature to the minimum
temperature needed to melt your solder and have it flow smoothly.
| Alloy |
Tin ‰ |
Lead ‰ |
Solid to |
Liquid at |
Pasty Range |
| 50/50 |
50 |
50 |
361º |
421º |
60º |
| 60/40 |
60 |
40 |
361º |
374º |
13º |
| 63/37 |
63 |
37 |
361º |
361º |
0º |
-
60/40 Solder: Composed of 60% tin and 40% lead, this solder melts at
374 ºF, but doesn't become
completely solid until it cools to 361ºF. This means it has a "pasty range" or "working range" of 13 degrees.
-
50/50 Solder: This is composed of 50% tin and 50% lead. It is liquid at
421ºF, solid at 361ºF and has a pasty range of 60 degrees.
-
63/37 Solder: This solder is 63% tin and 37% lead. It becomes liquid at
361ºF, and solid at 361ºF, with a pasty or working range of 0 degrees. This solder is called a eutectic alloy which means at
361ºF, you can go instantly from solid to liquid to solid just by applying or removing the heat source.
-
Lead-Free Solder: Depending on the specific mix of metals, lead free will produce differing liquid, solid, and pasty range temperatures. Check with the solder manufacturers for these specifics.
- Keeping the tip clean is important but constantly wiping it on a wet
sponge can cause early tip failure. Wiping causes the tip temperature to
drastically rise and fall and the different metal layers in the tip to
repeatedly expand and contract. This cycling leads to metal fatigue and
ultimately tip collapse. The more frequently you wipe the tip, the more you
stress it.
- Pushing the solder into the tip to force it to melt or rubbing the tip
against the joint to force heat in will destroy the tip faster. Allow the
iron to heat to the soldering temperature where normal contact of the solder
with the tip causes the solder to melt.
- The lower the tin content of the solder, the more difficult it is to keep
the tip from loosing its protective coating of solder (dewetting). Keep a
roll of large diameter 63/37 on hand to periodically flush and re-tin your
iron tip.
- Match the diameter of the solder to the tip. Using small diameter solders
may not keep the tip flooded with solder while in use and cause the tip
oxidize and wear faster. Use large diameter solder or periodically flood and
tin the tip using large diameter 63/37 solder as suggested above.
- The more active the flux, the faster oxidation on the tip forms requiring
more frequent tip cleaning. Using a flux with the lowest activity possible
will help reduce oxidation and corrosion and maximize tip life.
For a list iron and tip maintenance suggestions go to tipcare.htm

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