Is it possible to place components on both sides of the board if I'm doing DIY toaster-oven style reflow soldering? I would think that doing the reflow twice (for the other side) might overheat the components already soldered on.
Electronic – Components on both sides of the board with reflow
reflowsoldering
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If you can get hold of a dissecting scope and some decent tweezers, you could probably solder all those parts in about 2 hours. I've done a similar board with around 125 components in about 3 hours.
Here's my setup.
This isn't to say that you shouldn't use an oven-- I haven't tried that; it might be better. Seems a little bit like all your eggs in one basket, but I guess you could always rework parts in either case.
I reflow in a Skillet. Most skillets and toaster ovens I have seen go to 350-400 Farenheight, which I don't think is enough for lead free solder.
The real benefit of a skillet is you can watch the parts on the whole PCB as they reflow, so you are not depending as much on your temperature profile being right. You can see the solder paste first turn a grainy/shiny and then shiny. I also use an infrared temperature gun to maintain the right temperature for soaking.
In my case I had to buy a piece of plastic and put bolts in the corners for leveling the skillet. I also had to run a fan on the skillet after reflow because it didn't cool quickly enough.
Best Answer
I have seen this done with a two step method.
The most professional way I have been taken part in involved all of the components have a bit of glue sticking them down(technically epoxy). The oven then would heat the top side to the correct temp, then the board was flipped and the board had the top heated. This was being used by a firm that created products exclusively for the military and I believe had strict requirements on reliability and I believe their oven method was very reliable.
I have also seen methods where people use high temp epoxy and then just bake the whole thing at once. You need things lined up carefully because the epoxy will stop things from moving around and normally during reflow parts move into their proper position on the board almost automatically.