The Healthy EC Dev-Rev1 PCBs came in the other day. I wanted to know how our old toaster oven would work as a reflow oven without any modifications. Using an old toaster works well enough that I’ll use this technique again! The tedious part continues to be -and will always be without a pick and place machine – is the placement of solder and placing of chips. Although it is a great time to relax and listen to music.
I set the toaster to 475˚F and warmed it up for 10 minutes. After putting the solder mask and placing the chips, I popped it in the toaster for ~ 90 seconds….and out comes….
not bad. There were two 0805’s that needed to be re-soldered, like the tombstone job on R18:
and my old friend the MCP3901 needed cleanup:
but these were minor – and easy – to clean up.
To evolve my soldering technique, I note:
- I used too much solder. I tend to place a glop that covers a pad. After playing with a stencil, I believe a better method would be a light covering – more like a smear – than a glop.
- The paste I am using – as Brent from Osh Stencils noted based on an earlier post on using stencils is very (very) liquid. I was hoping it was because I had removed the solder paste from the refrigerator an hour before so that it would be at room temperature as Dave (EEVBlog) advised in this video. No, the paste I am using – Chip Quik Low Melting Lead Free Solder Paste – is liquid.