Recently I decided that it was high time I tried to reflow a circuit board.  Previously I had been waiting to create a circuit to control the toaster oven, but I thought “Hey, what if I just control the oven by hand.  That should work out,right?”

Unfortunately, the heating profile was pretty lousy.  The heating elements scorched the phenolic (paper) circuit board, and the solder reflowed at a much different temperature than it should have.  My guess is that the direct heat from the elements creates high localized temperatures, even though the oven temperature might still be quite low.  In order to improve the heating profile, I’m going to add metal covers around the heating elements in order to diffuse the heat.  A fan will be used to circulate the heat around the oven, and I will probably break down and build the controller for the oven.