I need someone to explain this to me.

Solder reflow toaster oven

[Sebastian] needed a small solder oven so he bought himself a small toaster oven (Spanish, Google Translate). It’s not the kind of thing we’d make our breakfast in now, but for soldering it’s a very nice oven.

After a little bit of research on Google, [Sebastian] discovered that the best technique when dealing with reflow ovens and solder paste is following a specific temperature curve. Ideally, Tin/Lead solder needs to preheat from room temperature to 150 degrees C, then level off so the flux can activate. After that, a quick jaunt above 183 degrees C makes the solder flow. To get his toaster working optimally, [Sebastian] stuck a thermistor in the toaster and measured the temperature profiles of different ‘modes.’

The correct temperature curve was calculated using different heater elements and [Sebastian] was off to the races. He did have a few problems on his first few boards – solder bridging, mostly – but that’s not the fault of the oven. An LCD display (translate) was added recently so accurate real-time temperature monitoring is available.

SMD soldering practice kit


Here’s an interesting kit put together just to help you work on your SMD soldering skills. It’s got 49 SMD LEDs on the front with a programming header and switch jumper. The back has an ATtiny26L and a coin cell. At only 3V, power management is essential; all of the example programs are only addressing one LED at a time (imperceptible to the human eye). If you turn on too many LEDs at the same time, the voltage drop could cause the AVR to reset. Included example programs are a scrolling marque, bouncing balls, and Conway’s game of life. SparkFun has tutorials for regular SMD soldering and using a reflow skillet. The video below shows the kit builder attaching just one LED using the heat and slide method.

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