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A DIY reflow oven

A Raspberry Pi with an Adafruit MAX31855 thermocouple interface board and a solid-state relay is used to control the temperature profile in an oven for reflow surface-mount soldering. The software running on the Raspberry Pi is here: The instructions in the file in the picoReflow project are good, with one modification needed: to auto-start on power-up, the reflow script in lib/init needs “#! /bin/sh” on the first line of the file, not line 12 as given.

I set my Raspberry Pi with a static IP address of, so the address to browse to see the oven interface is

The oven used is an Argos Cookworks 20L 1380W model with top and bottom heaters. The heaters are connected in parallel. Extra insulation is added around the top and sides of the oven chassis and in the door. The seams are sealed with high-temperature putty. Some cross-bars in the rack are removed to reduce thermal mass.

The unmodified oven
Resistance of bottom elements
Door insulation
Complete: gold reflective tape covers seams and glass surface of door
Rear label
Resistance of top elements (two in series)
Sealing the joints
Internal wiring