A very detailed reflow oven build


If you do a lot of SMD soldering, a reflow oven is the fastest and most efficient way to get all those tiny components attached to your PCB. [Frank Zhao] saw the reflow ovens we featured here over the last few weeks and figured he might as well show off his rig as well. We’re certainly glad he did, because his very thorough writeup is a great stepping stone for anyone looking to construct a reflow oven of their own.

Like many others, he started off with a used toaster oven, modifying it to be controlled directly via the power cable rather than the oven’s dials. He built a small PCB to regulate the oven, which features an ATmega32u4 and thermocouple to keep the temperature in check. Control of the heating element is done using a solid state relay, for which he built his own heatsink.

He studied the reflow profile of the solder he would be using, programming the microcontroller to regulate the heating/cooling process without requiring any user input, aside from turning the oven on.

Check out the video below to see a brief overview of his system, and be sure to swing by his writeup to take a look at all the build details. There are a handful of additional videos along with plenty of pictures there, walking through each step of the process.

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Heater for bending acrylic

We like using acrylic in our projects but there are a couple of tricky techniques, particularly getting clean cuts for glued edges and bending the material into curves. [Giorgos Lazaridis] has a great solution to the latter, a dedicated acrylic heater. Instead of using an oven to warm the material for bending he’s using localized heat produced by a high-powered lamp pulled from an old laser printer. The next part of his solution is to keep the heated area of the acrylic as small as possible. This was achieved by creating heat sinks on either side of the bulb. The metal bars seen above have water running through them to help isolate the softening of the material to a narrow strip. See how well this system works in the video after the break.

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Building a crystal oven

Radio communications depend on stable oscillator frequencies and with that in mind, [Scott Harden] built a module to regulate temperature of a crystal oscillator. The process is outlined in the video after the break but it goes something like this: A small square of double-sided copper-clad board is used as a base. The body of the crystal oscillator is mounted on one side of this base. On the other side there is a mosfet and a thermister. The resistance of the thermister turns the mosfet on and off in an attempt to maintain a steady temperature.

This is the first iteration of [Scott's] crystal oven. It’s being designed for use outdoors, as his indoor setup uses a styrofoam box to insulate the oscillator from ambient temperatures. He’s already working on a second version, and mentioned the incorporation of a Wheatstone bridge but we’ll have to wait to get more details.

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Powder coating at home

[j_tenkely] wanted to do his own powder coat painting at home so he built everything he needed, including a coating booth and baking oven. The oven is double walled and built around a frame of steel building studs. Electric oven elements are controlled by a digital control panel and thermostat.

A spray booth is fashioned from a large storage bin. The powder coat gun used in this setup is a commercial project. But don’t fret, this is something you can build rather than buy.

[Thanks goat]