Soldering How-To

A crash course for building DIY Eurorack-modules or other soldering projects

You may have come here since you bought one of our kits, or because a search engine brought you here. Welcome and thank you. This page is intended to bring you up to speed for DIY soldering. Please take the time and read through it, even if you are an experienced builder. One or two things might still be relevant to you and will help you to get a functional module and save you arduous bug hunting and problem analysis.

Tools checklist

Essential:

  • Soldering iron with a fine tip and temperature settable, so you can adapt it to the tin you are using and the speed you are working with. We have an ERSA i-CON soldering station as well as a Pinecil. Watch this video about proper soldering iron care.
  • Soldering tin without lead. Our favorite soldering tin is Felder Sn100Ni+ which has a low melting point but is strong and good to handle. Lead is a dangerous toxin, linked to harmful behavioral changes (aggressiveness) and is especially dangerous for children and during pregnancy. There is no reason to hold on to leaded solder, even if many old-schoolers still propagate it. Never the less: Stop touching your face during soldering work and wash your hands. No handling of snacks during work. Want to learn more? Check out this Hackaday article.
  • Brass wire sponge to clean the soldering tip. Use dry brass wool and avoid a wet sponge to reduce temperature stress and wear of the soldering tip.
  • Wire cutter like the popular KNIPEX ESD
  • Multimeter to check for shorts, measure voltages and identify resistors.

Beneficial:

  • Inflammable mat to work on
  • Oscilloscope
  • Solder sucker (also called solder pump)
  • Solder wick

Soldering technique

Timing and temperature must be good when soldering. Follow these steps:

  1. Heat the solder joint (both parts, the pad and the lead!). 3-4 seconds, if the pad has a ground connection, it may take longer due to the dissipation into the ground fill. Maximize the contact area between iron tip and pad/wire for best heat-transfer. Add some tin on the tip of the iron to increase the contact area.
  2. Keep iron tip in position and feed tin into the solder joint. Not too much and not to little (refer to chart).
  3. Give it some time to flow and fill the hole (1-2 seconds). The soldering iron is still in place.
  4. Let it cool. Remove soldering iron, but do not move the component. The solder joint must cool down and harden without adding stress to it.
  5. Now cut the lead off with he wire cutter.

Chart to check your solder joints.

Technique with photos

Still questions? Post them in our forum https://discourse.chair.audio/c/hardware/eurorack

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