I use a digital Cuisinart convection oven for reflow solder work. It’s cheap and effective, but the temp controller is slow to react and often overshoots with slightly blackened boards as the result.
Seeing a $5.- oven rack thermometer at the local supermarket, I couldn’t resist. Of course the metal case of the unit made it even slower to respond than the oven controller! I pulled the guts of the thermometer out and high temp epoxied the unit to the front glass of the oven. It does the trick and doesn’t even need to be plugged in! Hope this helps the other (cheapo DIY) reflowers out there…
Ron