Non-combustible joint compound??

Does anyone know of a non-combustible joint compound? I want to seal the seams of my wonderboard and I have used thin-set so far but it looks like crap. I want to get a smoother surface. I am using regular joint compound for other seams that meet clearances to combustibles but need something that can get within two inches of connector pipe.

Joint compound is not all that combustiable. What I will do is take a harden piece and expose it to map torch and report back my findings. If tape is involved, then there is a product called fire tape, used to tape seams in fire resistant walls. I will report back my findings after my torch test

I applied the map torch to dried joint compound it got to cherry red but did not ignite. There is no way your double wall pipe will ever approach, the temp I applied with the map torch. It did not ignite. I can confidently say, you are in no danger igniting joint compound from the heat given off threw or in contact of a double wall pipe.

Wow, thanks elk. This is the part where the double wall meets the single wall pipe. Actually, the single wall travels out a few inches through the wonderboard wall to meet the double wall pipe. So, the heat from the single wall pipe is present on the seam. The single wall is at least 1 1/2" from the actual wall-there is an air space there from where I cut my hole and a plate goes around the pipe and covers the hole in the wall. Do you think the joint compound is still safe? Anyway, I have become much more comfortable with the stove and MUCH less paranoid. It has been great. I got two more cords or wood delivered for a fair price so I'm feeling good. Can't wait till next year to get free wood at my family's farm!

I doubt there exist a problem. The heat I applied far exceeds any cconditions your single wall pipe will duplicate note it did not ignite

What about using that high heat caulk for the area immediately around the pipe? Also, how
'bout mixing some quick setting cement and troweling it onto the joint? That would make a nice smooth joint for sure.