For a few months I used to tape scrap PCBs on my work desk and apply solder paste there. It was the quick no-brainer solution, but the more designs I had to assemble the more issues I started having with this method:
- I could not accomodate more than 3-4 stencils at one time
- it was pretty annoying to keep exchanging the stencils and rearrange the outer PCBs
- it was taking a lot of space on my work desk even for only a few small stencils
- Since everything was taped down, I would always have to be careful not to work in that area and bend/damage the stencils
So it was time to step up a little. I had some left over MDF material from making the workbench top plate, perfect for what I had in mind. I like quick solutions that return a lot on the little investment I make. Here are the steps:
- Cut some PCBs in strips of approximately the same width. I used my tile wet saw to make quick straight clean cuts in FR4 PCB material. These will be aligned at the top and sides of the PCBs I will apply paste to.
- Use a large drill bit to gently expand holes for small screws. I had some existing holes and I had to drill some from scratch as well. I generally kept the drill holes away in far corners from where I would work with the stencils. Then I aligned them to a straight line and marked the center spots and drilled pilot holes with a thin bit.
- Apply screws and use the real PCBs as placeholders to help with making slots where they would fit for paste application. This way I can make many slots along the top row which is fixed, and if necessary move/adjust the sides if I no longer need some slots. Since I’m using scrap material I don’t mind if later on there are leftover holes. The screws will keep the slots tight and prevent them from moving.
- Additional slots are made the same way. A single such piece of MDF will accomodate many stencils. A potential improvement would be to cut the fixed PCB strips to the exact same width and them in the middle of the board, such that slots could be attached on both sides, and thus double the number of possible stencils. But for me this works, and I can always make another one if I need to. Tape down the home made metal stencils and ready to apply paste!
- Done! I can now enjoy some badly needed extra space on my desk, and a more convenient solder paste jig that can accommodate all my stencils, and which doesn’t have to be in my way when I’m not assembling PCBs. I know you can go crazy with making such jigs, laser cut or machine them, spend hundreds of dollars to buy an expensive solutions. It’s not a perfect nor permanent solution but it solves a bigger problem and allows me to scale and streamline my small operation. And the best part: it’s dirt cheap, made this one in under 1 hour from scrap parts. For large PCBs you might need a bigger board but it might also work.