Lead-Free Soldering Tips and Tricks

by Andy on February 10, 2012

Kester Lead Free Solder Wire As the soldering industry grows and matures, more emphasis is being placed on green processes and technology. This emphasis is coming both from governmental regulations like RoHS and personal convictions to save the planet. However, it can be a struggle to find environmentally friendly alternatives to industry standards, such as leaded solder. Even when we do find a suitable replacement, the difference between the new and the old can’t be overlooked. Proper knowledge and training is needed to get past the challenges that new environmentally friendly technologies pose, and to ensure the new methods meet the standards of the old.

In the electronics industry many are finding problems with lead-free soldering. Many see lead-free solder as hard to use and think the quality is subpar when compared to leaded solder. There are many issues that may not be taken into account, and there are things you can do to increase the effectiveness of lead-free soldering. By following these tips, you can increase the quality of your soldering joints as well as the life of your soldering tips.

Make sure your soldering iron can handle the requirements of the lead-free solder

The melting point of lead-free solder is typically 70-110°F higher than leaded solder. The typical response is to increase your soldering iron temperature. However, a good soldering iron with accurate temperature control and good thermal recovery can solder lead-free solder and leaded solder without the need to increase the temperature. Using a higher temperature will burn through soldering tips faster and potentially damage your PCB’s. Using the same temperature demands a longer dwell time to heat the solder to its melting point which can also potentially damage your PCB’s.

Take your time and do not increase pressure to force solder to melt and flow

Lead-free soldering can take longer to flow due to its higher melting point, so it is important to be patient. If you try to move too fast can lead to a weak or insufficient solder joint that requires reworking. If you press your tip against a joint too hard then it can damage your soldering tip/iron and the PCB or the component/wires you are soldering. Also, increased pressure doesn’t decrease the dwell time.

Kester Lead Free Solder Bar Be prepared for lead-free solder joints to look different than leaded joints

When soldering with lead, the joints are typically shiny and smooth. However, lead-free solder joints can look dull in comparison. This is normal, so you do not necessarily need to rework your lead-free joints if they are dull.

Keep your solder tip clean and coated with solder

Due to the high temperature of lead-free soldering, tips will tend to wear out faster. Higher temperatures lead to faster rates of oxidation, which can eat through the iron coating of solder tips. By properly cleaning and preparing your soldering tips, you can ensure the longest tip life possible.

For more information you can check out the United States Environmental Protection Agency’s Life-Cycle Assessment on lead-free soldering. There is also an interesting article about some of the challenges of lead-free solder on Hakko’s site.

Have you tried lead-free soldering? Tell us in the comments below why you like or dislike lead-free soldering and if you have any tips of your own to share with us!

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