Ask Me Help Desk - Mainline backup with clay in cast iron pipe (with image)

I have a mainline problem. I have, what I think to be clay, backed up in my drain. I'm not sure if I've got a broken pipe and am digging into the ground or if there's just a lot of clay to go through. Regardless I rented an electric eel from Home Depot and have been at this thing for 2 days now, a couple hours at a time. I only have enough room in the pipe (2 inch pipe) to use the diamond shaped blade. I've got a layout of the problem (see pic 1). The arrow points to the only opening I can use to put the snake into the drain. The blue is water and the brown is the clay. The "working" is another drain entry downstream that drains properly. I'm just not sure how far I'm going into the drain though (I need a plumbing camera). My question is this... Should I just continue what I'm doing as I don't feel like I'm getting anywhere? Or is there a certain way to get rid of this clay? Or is it possible something collapsed? I have well water with public sewer and everything after the point where the clay is jammed up seems to work properly. I'm just not sure where this clay came from or how to get rid of it. Any suggestions are welcome. Thanks in advance for your help!

Pic 1
http://www.chrisohara.org/drain.gif

Unless you are used to try to flush huge amounts of clay through blocked sewerage pipes : what makes you think it is clay? Most probably it is just a blockage of a normal sort : different materials combined with fat.

Drop two big cups of caustic soda chrystals in that inlet, and follow that up with a couple of buckets of hot water (the hotter the better). Please be careful : there may be some splatter !

Most of the time this will solve the problem.

Success !

Quote:

I'm just not sure how far I'm going into the drain

You hit on the problem of snaking from where you're going in. The problem with going in that way is you never know after the snake gets past the sanitary tee whether it will go down into the clog, (and how do you know it's clay? )or turn up into the stack. A better way would be to snake from the roof vent. Good luck, Tom