Reflow vs Soldering – Ouch! reflow is easy

Soldering SMT components onto PCBs is not so easy, or is it?

Let’s look a little at SMT (Surface Mount Technology) vs PTH (Pin Through Hole)

Makers tend to work with PTH printed circuit boards for various reasons but mostly because they know them and know how to assemble them on the PCB layout. But by choosing PTH you are limiting your ability to make and grow as a maker.

Pros of SMT components

  • Cheaper
  • Tidier assemblies
  • Smaller printed circuit boards
  • More choice of components
  • Multilayer printed circuit boards

There are people who prefer to solder these teeny, weeny components and I genuinely take my hat off to you. I do not have the steady hand or eyesight to manage it. I prefer to reflow which as we all know is how the professionals do it.

So what is reflow soldering?

Reflow soldering is a process in which a solder paste (a sticky mixture of powdered solder and flux) is used to temporarily attach one or several electrical components to their contact pads, after which the entire assembly is subjected to controlled heat, which melts the solder, permanently connecting the joint.

You need solder paste and heat. The correct profile is a little difficult but many people manage it with toaster ovens or hot plates.

There are options to make this process a little more automated from the professional offering such as EuroCircuits eC-reflow-mate to the more affordable

Reflowster (a little truth here we like the Reflowster so much we use it at all our workshops and selling it on our website in our pcb shop– I just thought you should know).or you can always build your own, there are lots of open source designs out there.

“But the point is whatever your budget reflow soldering is not expensive and it’s a perfect fit for any worktop or workshop.”

For larger components you can place the solder paste on the PCB using a syringe or you can get a stencil. For makers we recommend plastic stencils they are reusable and cheap. We use in the UK for our ‘Hardie Kids’ workshops.

Once the components have been placed you can reflow your printed circuit board.. We use a bog standard toaster oven and the Reflowster. The Reflowster controls the temperature of the oven and creates the temperature profile needed to reflow. Once the device beeps and the blue light comes on just take the PCB, don’t forget the PCB is hot is just been in 230’C.

Once cooled take a look at your beautiful PCB assembly.

Now wasn’t that easy.

PS This series from Wayne and Layne on SMT is really good