The Advantages of Solder Paste Application The process of pre‐applying solder paste to the board, then resting the component upon the solder paste areas, starts to make sense. The likelihood of a quality placement increases, since the solder paste is evenly spread under the component prior to reflow. The question now, however, is how to apply the solder paste in such a successful way. That’s where the stencil comes into play. What is A Stencil? Stencils are customized to the board you’re assembling. Generally speaking, the stencil is made out of a solid sheet of material (aluminum, copper, and mylar are common). There are generally two ways to obtain your stencil: make one yourself, of have a stencil company make one for you. Making Stencils Yourself Limor Fried, the founder of Adafruit Industries, and a highly influential force in the DIY community, has a great page on how to make your own solder paste stencils. I love how her instructions start…. “You’ll need: 1. A laser cutter.” Now, some of us have access to a laser cutter, but that becomes a pretty big barrier for many of us. Some searching on the internet shows reasonable desktop models for sale in the $5,000 range. I suppose if you’re really mechanically inclined, you might consider building your own laser cutter for less. A deeper search for laser cutters you can build yourself uncovers the instruction set that explains how you can, for about $50, build your own laser cutter out of parts. The last item on the parts list? “A bushel of patience.” Further research leads us to an open‐source, build‐your‐own laser cutter kit. Quote from the Lasersaur people, developers of an open‐source laser cutter: “Laser cutters are traditionally expensive ($30,000 to as much as you can spend) and there are a lot of … designers… who could do great things with them ‐ if they could afford one, or even get regular access to one. Unfortunately, turnkey systems are expensive, and there isn’t really a clear and simple way to build one. We can change this: with roughly six months of R&D time we can develop a laser cutter which anyone can build, use, and maintain. Most importantly this system will be open source which means anyone can improve and modify the design. So, faced with this sort of an environment for getting your own equipment to help support you in creating your own stencils, the make vs. buy decision takes on another dimension: using a service to provide your stencil as a part of the manufacturing process.