Just found this thread and in a bit of a crisis.

Read somewhere that bi-carb and vinegar can be used as a drain cleaner. I won't have drain cleaner in the house and my laundry sink is blocked something awful. Had to stop washing machine because draining SOOOOOOO SLOWLY that it's flooding the floor.

Anyone know the ratio of bi-carb to vinegar to clear blocked drains? So glad my laundry is external right now >.<

Thanks in advance!
Here is the Lush House method:
Pour a quarter to half a cup of bi-carb soda (alkaline) onto the drain. Wait 20 minutes and add a cup of white vinegar (acid). A chemical reaction occurs whereby oxygen is forced into the mix and scours the pipe. Wait a couple of minutes and pour a jug of boiling water into the drain to flush it clean.
I have done the same in the past, but never really bothered with measurements and had it still work.