I failed something awful at this over the weekend; I think I started too close. Is there a specific strategy? After I ate two battering rams and was taking ~79k hits, I went down in no time at all. Got the boss to maybe 50% health.
I managed to drop him in a Demolisher with full pyrite. Just constantly pelt him with pyrite and he should die real quick.
I actually tried sarth 3D on 10 with my druid and wasn't able to do it. That was when I still had some blues though I haven't tried it recently. I got him down to about 15% health and all the adds just overwhelmed me. I would say it is very possible though with the right skills/gear. I think my Ilvl was around 472ish at the time.
You need about 42k dps min to drop him before he goes immune. Ignore adds and just focus the boss (and avoid waves). Save your survival cooldowns when he gets around 10% (might be 15% or 5%). You want it up so when the drake that is poking you in the butt enrages and starts hitting rather hard. Nothing "OMG" hard but hard enough that it can easily wipe you if you are sloppy.