Didn't notice this before, but apparently the previous 2 fires (bakeout & 1st cook) caused some thermal stress. The JB'd bottom, firebox and fire ring are all fine. But new cracks have propagated from the original ones that were JB'ed in the dome.
Crack growth in dome - close up.
DRAT!!! I thought the two previous firings were low and slow. Maybe not?
This calls for new JB-epoxy application PLUS FireStop furnace repair cement ! ! !
However, Humpty has been committed for tonight's dinner (and tomorrow too)!!! Invitations have been issued and accepted. Food has been bought and prepped. 
*** So, I'm going ahead and cooking on Humpty anyways. ***
As precaution, the dome will be reinforced with wire around the neck so that it doesn't collapse. Will also be careful to keep the temperatures below 400F.
There will probably be more crack growth due to thermal stress from the additional firings. If the dome cracks right to the edge, JB application next time should work better because the epoxy can then be applied INTO the cracks (instead of on the surface).
I will deal with all this AFTER the weekend, after all the guests have left.
Moral: Look at things in the day(light).
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Project Humpty:
SLIDESHOW,
PHOTO ALBUM