It's quite feasible to do reflow soldering by applying solder paste with a stencil and then using a cheap toaster oven. However, the lack of a precisely control

It's quite feasible to do reflow soldering by applying solder paste with a stencil and then using a cheap toaster oven. However, the lack of a precisely controlled temperature profile makes it less repeatable and reliable than the industrial process. I've done it successfully a few times but generally had to touch up one or two components with a hot air station or soldering iron. Here's a SparkFun blog post: https://www.sparkfun.com/news/3319 https://www.sparkfun.com/news/3319