Ok, I have this reflow soldering working very well... First I tried just (1) board, success.
Then on my 2nd attempt, I tried 4 boards at the same time. Everything worked.
This is better than I expected!
I was planning on buying a real reflow oven and this toaster oven is just to tide me over, but I think I'm going to stay with the toaster oven.
I set all my boards on a tray (that came with the oven). Then I hook up a temp probe from my Fluke meter.
1. Set oven to "PIZZA" setting and 450C.
2. Set Timer to 10 min. (no worries, it's not really going to stay in the oven for 10 min.)
3. Preheat toaster oven until 100C. (takes about 1:00 minute).
4. Open door, insert tray (containing all the populated PC boards).
5. Temp in oven will rise to 200C. (takes about 2:00 minutes)
6. Turn OFF power to oven.
7. Temp will continue to rise even with power OFF... around 210C or so, everything will start reflowing. This happens pretty quickly.
8. wait for it... Let it reflow some more, when temps reach around 240C, open oven door, and take the whole tray out. (be careful, hot and don't bump the tray into anything)
9. Set tray on top of oven gently. Temp will be now in the 245/250C range.
10. Get a piece of cardboard, and fan it manually.... or point an electric fan to it. Temps will rapidly go down proportionally to how much you're fanning it.
SIMPLE PLANNED MOD:
I'm thinking cutting out a square hole opening in the back of the oven.
Then using a .125" aluminum sheet, bolt it to the back of the oven.
On the aluminum sheet, there'll be a cutout for a 120VAC 4" fan (Radio Shack sells them, steel frame, not plastic like computer case fans)
I'll use this for EXHAUST, and just flip a switch to activate it.
If I can find a suitable lamp and socket for this, the lamp can also be mounted on the .125" aluminum sheet.
Next step... just write a simple Arduino program (just relying on timer() to time when to turn OFF oven and turn ON exhaust fan. No need for PID and all that complexity.