When the paste starts to flow the reduced friction will allow certain components, especially inductors, to fly across the board as they are attracted to the magnet, causing a hot mess. DO NOT use the fancy science hot plates with the magnetic stirrers in them. Generally you want to move the PCB around with tweezers or needle-nose pliers during this process, as there will usually be hot spots and you want everything to flow at roughly the same time. Then you place the board on the hot plate and wait and watch until everything has flowed, then wait a little longer until most of the flux has burned off, then you take it off the plate. Usually around medium heat is a good setting for most of these plates, and you know it’s ready when you can put some solder on it and it turns to liquid. This involves an electric hot plate ($20 investment). Starting off with the most basic tools available we have the hot plate or griddle method. Some breakout boards are just starting to flow. Hot Plate A hot plate with aluminum on top. Scaling it up and doing it repeatedly with high yield is extremely challenging, though. Accomplishing this once or twice is easy once you’ve played with a hot plate you’ll swear off through hole. There are a variety of methods for reflowing a circuit board, but they all rely on a single principle: heat up the solder paste (a mixture of flux and solder) until the flux burns off and the solder becomes liquid, and then cool it down.
![reflow soldering process reflow soldering process](https://i.ytimg.com/vi/Yk2dsYG4OvM/maxresdefault.jpg)
![reflow soldering process reflow soldering process](https://www.surfacemountprocess.com/uploads/5/4/1/9/54196839/1662536.jpg)
![reflow soldering process reflow soldering process](https://wsbenelux.nl/wp-content/uploads/2020/11/Heller-1826-MK5-1024x681.jpg)
REFLOW SOLDERING PROCESS SERIES
In our previous issues in this series on making circuit boards, we covered placing solder paste and placing components.