cmiyc wrote this Instructable: Polyimide (Kapton) PCB solder paste stencil
Creating a solder paste stencil for a toaster reflow oven or hot plate is simple when you have access to a laser cutter. I used the Laser Cutter at my local TechShop to create this and other PCB stencils.
This Instructable assumes you have created a PCB and are able to generate the Gerber Files for it. Specific directions will be given for EAGLE, but other PCB software can be used. The board used in this example is an Arduino RTC Shield based on the DS3231. Follow the link for the EAGLE design files if you want to follow along.
Via Electronic Lab.
Kapton stencils are fantastic for prototypes. I don’t have direct access to a laser cutter so I use a service from Ohararp, LLC. You can get a letter size stencil or up to six smaller stencils for $25 shipped. Stencils arrive in a few days. I’ve had great success with 0.5mm QFNs and 0402 passives.
I tried a new service this week. OSH Stencils The quality was fantastic, and the prices are very low. They only charge for what you use, so it’s more friendly on my wallet when I only need a single 4-5 inch stencil. Cost me $5 shipped.