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SMD Reflow Oven – DIY Build

SMD Reflow Oven – DIY Build

Decided it is time to get a reflow oven together (my boards are too tiny to solder with an Iron (I guess. But this will be easier anyway).

Step 1:

Find a cheap, 2nd hand mini oven.

Done – This thing is Tiny. I would be surprised if you could even cook a mini-pizza in this.

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Put a thermocouple in this oven, and tested the temperature. It takes a long time to get up to the reflow temperature. So time for some mods:

1) Strip out the Timer and Controller.
2) Take out the bottom elements, and reinstall them in the top.
3) Install a PID Temperature controller.
4) Insulate around the cavity to prevent heat loss.

Ok, So Time to start stripping :

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Oven has been stripped, New holes drilled, and the bottom elements have been relocated to the top (sorry, no pics yet).

Wired the elements in parallel and hooked up a PID temperature controller in place of the Timer/Switch combo. I also bypassed the thermal cutout on the sidewall of the oven.

Put a populated SMD board in the oven, heated up to (what the controller says) is 165 degrees centigrade, with the thermocouple in contact with the PCB, and the solder melted. I was able to remove all the components with a gentle tap.

Oven actually got up to 250 degrees c, but the door was rather hot.

And this was without any additional insulation in the oven (and the top cover still removed),

I have taken plenty of old boards I had lying around, and after sticking them in this oven for a bit, As soon as the solder melts, I pull them out (with a pliers) and bang it on the workbench.

The results : An almost Empty and Clean board, Solder Splatter all over the workbench, and small parts all over the garage!

For Fun I cranked up the temp, and had a GPU chip (from a monitor card)on the rack, After tapping it, the ‘lid’ came off the processor, and i could see all the bond wires. That was unexpected

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