This is a problem that seems so simple yet it's turning out to be SO hard to fix!
I pasted a picture below of the problem area. See that copper pipe on top of the small cast iron waste pipe? Well it fills with water and it is COMPLETELY blocking the sink above it. TO further research the problem, I removed the large bolted on iron "U" that you see to the right which exposes the large vertical pipe. It is completely clear. So the problem is in that 3 feet or so of cast iron pipe that feeds into the large pipe. So I could get at the area better, I removed the copper pipe from the top.
The clog is DEFINITELY in that "feeder" pipe. I'm betting it's organic. I have a hand snake, but that just pulls up small amounts of gook and makes no real progress. If I stick a rod down the pipe, I hit something very hard which is probably the iron bend near the bottom.
All I want to do is STOP messing around with this plumbing! What is the best way for me to clear that clog? Is there some highly nasty chemical that eats everything but iron I could pour in there? It's VERY frustrating to know where the clog is but no be able to clear it.
Any advice would be gratefully received.