I was thinking of trying it, but would like some tips such as sources to get the materials, safety, etc. I've already looked at the Kester solder paste and plunger on Digikey, but I haven't seen any tips, yet.
I have a PCB ready. Most of my components are 0805 SMT packages, but I have a a few 0603s. I also have an IC that is a TSSOP package. I already tried hand-soldering, but I failed miserably. I only have a couple of parts left, so I'd like an easier but reliable method. If I had the money, I'd go straight to a local PCB assembly house, but then again, where's the fun in that, huh?
Yeah, I've done a few simple boards with it. It works rather well, actually. Just have to be very careful with the amount of paste you put on the board, and how close any copper fill comes to the pads
*underneath* the chips. I've been adding restricted zones to increase that gap after I had a chip or two bridge to the copper fill, which isn't solvable without completely starting over. (This is on home-made boards with no solder mask)
Another site, can't remember off the top of my head atm, suggested that instead of a toaster oven, you use a cheap skillet. I bought one for ~$20 at Target and have had better luck with that so far, at least for the tiny SMT->DIP adapters I've soldered up so far. A properly selected one will make fume extraction easier (I replaced the top handle of the lid with a small rubber tube which I'll be attaching eventually to a home-built fan exhaust to outside), and visibility is definitely better. The main advantage is that the heat comes from the bottom through the board, and is therefore a bit more controllable. The site that suggested the technique was having problems with USB connectors melting before the solder did...
I had to check a local contractor-supply type place to get them. They came in a box of 50 (disposable) for about $20. Of course you're only going to use one, and changing sizes is out of the question unless you can find a way to get all the paste out of the tip that you're switching out. Go for a rather small one, maybe a metal-tipped one if you can, with something like a 10mil openning.
Well, in wave soldering, they cover the whole board with solder. The trick is, the solder (hopefully) won't stick where the mask is, between the pads. So, as long as you've put the right total amount of solder down, it will get pulled to the metal pads (surface tension et al) once it starts reflowing, and there won't be any between the pads.
You can still do this without a mask, as the solder usually won't stick to the PCB either, but the risk of bridges increases.
In the case of hand-applied solder paste, it's basically impossible to put an appropriate sided drop on every pad of even a SOIC. Since the PCB itself will not hold solder, as long as you have a string of it along the pads of the right thickness, the surface tension of the melted solder will cause it to ball onto each pin and flow properly.
It's actually very instructed to just give it a try and pay close attention to the instant when the solder melts (which usually occurs from one side of the board to the other, not all at once). You'll get a good feel for the surface-tensionn properties at that point.
A trick for dealing with variable placement of solder paste coming from the syringe is to shove it around carefully with a sharp dental pick. If you get a trailing blob off the end of the syringe somewhere, either pick it up and remove it entirely, or shovel it around to places where it's not as thick. If you do the chips first, you can move the excess to the discrete's pads.
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