Double-sided soldering in the Elektor reflow oven

Many readers have asked us if the Elektor Reflow is suitable for soldering components on both sides of circuit boards. It is, and the method has been tried and tested in the Elektor labs.

Here’s the method in a nutshell. You need to solder the ‘underneath’ SMD components first. Start by applying soldering paste to the solder pads, then a small drop of SMD adhesive between the pads, preferably in the centre of the location for the component being soldered. When heated, the epoxy-based SMD adhesive polymerizes and holds the component. Now place the components in their positions and solder in the oven using your favourite/usual reflow program. Tip: before starting the soldering process, check one last time that the components haven’t shifted while being moved to the oven.

Leave to cool down, and get ready for the next step: apply the soldering paste, this time to the ‘top’ pads, then place the SMD components. Here, there’s no need for adhesive. Solder in the oven using your favourite program. The underneath components won’t fall off, as they are glued.

Once the board has cooled down, all that’s left to do is solder the through-hole components using a conventional soldering iron.

Let’s get cooking!