My first thought was "I should melt something!". So I scrounged up my bag of old solder-contaminated crud that I've scraped off my workbench and soldering iron sponge over the last 20 years and threw that onto a tray.
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After switching on the oven, a large cloud of toxic smoke emanated from around the door and the ventilation holes of the oven as various "volatiles" burned off. After a few minutes I decided I'd better turn it off before the entire thing goes up in flames, and lo and behold! Solder was melted!
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I made a little divot in a smaller sheet of aluminium foiland poured in all the liquid that could be wrung out of the pile of scrap. Back in the oven for a bit of settling.
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And voilà! as the say in France, or "whalla" as they say in America - a nice, compact, and less environmentally-polluting (hah! I couldn't do it with a straight face) ingot of the old 60/40.
The following weekend (this one just gone) it was time to try real soldering. I used a little too much expired solder paste to place a resistor on an old HDMI mod board and chucked it in! After guessing where to turn the dial for the perfect reflow profile, I got a result.
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Next it was time to try making a 135-micrometer-thick mylar stencil on my 40W hobby laser. I tried both vector-cutting and raster-engraving the film - this was a disaster and none of my attempts came close to being usable. I gave on this idea after several failed experiments. The one that looks the best here happened to be in the same direction as the laser travel while engraving, but orthogonal to it it was rubbish.
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Well, I took a fairly flat one, without so much melting at the edges, cleaned it up with a pointy tool and gave it a go anyway. It basically worked if we define "worked" as "some solder paste went onto the board and stayed there".
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Then back into the infernal machine. (Somebody had recently told me my reflow videos needed some epic background music)
Quite a lot of bridged pins because of the excess solder paste, but it's a starting point. Next time I order boards I'll be sure to order a factory-made stencil, but in the meantime I can do it manually.
Interesting, I had been considering a reflow oven based on something like this, but with some micro-controller based Ben Heckery added for temp control and timer. Would be nice to at least have a pre-heater for hot air based reflow activities.
I will most likely set it on fire or cause another power outage at home....
Since I started playing around with non ST PSUs I have realised how much safer the ST design is compared to the Mac Classic analog board and the PSU from my Amstrad Alt386 portable, both of which caused power outages because of horribly exposed mains connectors.
There was a 3rd outage, but that was caused by a currant that came out of a toasted teacake which caused a short between the element and the chassis. Yes, a current through a currant. Maybe I should start a channel like Big Clive....
rubber_jonnie wrote: 11 Aug 2020 13:45
Interesting, I had been considering a reflow oven based on something like this, but with some micro-controller based Ben Heckery added for temp control and timer. Would be nice to at least have a pre-heater for hot air based reflow activities.
Great minds think alike! I have a stainless steel thermocouple and a roll of gold-plated infra-red-reflective tape (used on car engines) on the way in the mail. When they get here I'm going to start on the microcontroller part of the project. There's quite a bit of room inside the case on the right side so hopefully it can all fit in there and not get too hot. I saw that there are some good open-source projects posted in @Icky's toaster oven thread as well. I haven't done ANY research for mine yet. I was just thinking I'd just chuck an Arduino Nano and an SPI OLED display in there.
rubber_jonnie wrote: 11 Aug 2020 13:45
Interesting, I had been considering a reflow oven based on something like this, but with some micro-controller based Ben Heckery added for temp control and timer. Would be nice to at least have a pre-heater for hot air based reflow activities.
Great minds think alike! I have a stainless steel thermocouple and a roll of gold-plated infra-red-reflective tape (used on car engines) on the way in the mail. When they get here I'm going to start on the microcontroller part of the project. There's quite a bit of room inside the case on the right side so hopefully it can all fit in there and not get too hot. I saw that there are some good open-source projects posted in @Icky's toaster oven thread as well. I haven't done ANY research for mine yet. I was just thinking I'd just chuck an Arduino Nano and an SPI OLED display in there.
Ben Heck did a good video on it, so worth a watch, I just haven't had the time to do it myself yet. I'll be very much interested in your project here.