There are a ton of ways to go about building your own reflow oven. Most of these builds start with, well, an oven — usually a toaster oven — with a small but significant minority choosing to modify a hotplate. But this might be the first time we’ve seen a waffle iron turned into a reflow oven.
Of course, what [Vincent Deconinck] came up with is not an oven per se. But his “RefloWaffle” certainly gets the job done. It started with an old waffle maker and a few experiments to see just how much modification it would take to create the various thermal reflow profiles. As it turned out, the original cooking surfaces had too much thermal inertia, so [Vincent] replaced them with plain copper sheets. That made for quicker temperature transitions, plus created some space between the upper and lower heating elements for the SMD board.
As for control, [Vincent] originally used an Arduino with a relay and a thermocouple, but he eventually built a version 2.0 that used a hacked Sonoff as both controller and switch. Adding the thermocouple driver board inside the Sonoff case took a little finagling, but he managed to get everything safely tucked inside. A web interface runs on the Sonoff and controls the reflow process.
We think this is a great build, one that will no doubt see us trolling the thrift stores for cheap waffle irons to convert. We’ve seen some amazing toaster oven reflows, of course, but something about the simplicity and portability of RefloWaffle just works for us.
After his last project left him with an eleven-pound block of aluminum, [Jason] got to thinking of what most of us would in that situation: fresh made ice cream. His mind was on the frozen concoctions of the aptly named Cold Stone Creamery, a mall food court staple where a chilled stone is used to turn fresh ingredients into made to order sundaes.
[Jason] did the math and found that an eleven-pound chunk of aluminum can absorb a little over 67,000 joules, which is over twice the energy required to freeze 100 g of water. In place of water he would be using cream, condensed milk, and strawberries, but believed there was a large enough safety factor to account for the differences between his ingredients and pure water.
His first attempt didn’t go exactly as planned, but with his Flir One he was able to back up his theoretical numbers with some real-world data. He found that he needed to start the aluminum block at a lower temperature before adding his ingredients, and through experimentation determined the block only had enough energy to freeze 30 g of liquid.
In the end [Jason] was satisfied with the frozen treat he managed to make from the leftovers of his radial mill project, but theorizes that an ever better solution would be to use a brine solution and drop the aluminum block all together.
Of course, if putting food on a slab of metal from your workshop doesn’t sound too appealing, you could always go the NASA route and freeze dry it. Either method will probably make less of a mess than trying to print objects with it.