Ok, I figured I better do the work NOW than later. Better safe than sorry. After all, I don't want to do another major overhaul like this for at least 10-20 years!!! Too hopeful?
Went ahead and mortared the base. Low-tack Painter's Tape over the gasket.
Mortared the dome and firebox once more.
Have now applied 9 lbs (3 quarts) of furnace cement on Humpty. In terms of the number of coatings, the firebox was fully mortared 2X inside and out, the dome 2X on the inside, the dome JB welds 4X, and the base 1X on the inside.
I agree with Jim that the bubbling on his mortar (w/o JB) is probably due to trapped moisture. Which is why I'm not going to rush the drying process. Will let things air dry for about a week before firing up.
In fact, I will go the extra step of putting a kerosene or propane heater in the Kamado for 8-12 hours before doing the charcoal bakeout. The idea is to first drive off any residual moisture in a controlled low-heat environment before going to charcoal. This should help to minimize breakup, flaking or bubbling of the furnace cement.
I know I have to drive off added moisture as I actually wetted down the surface of the claypot and the cement during the mortaring process. Oops!
JIM: I hope your base survives!
Project Humpty: SLIDESHOW
, PHOTO ALBUM