Question about Drying Time for Furnace Cement

[Griz]

I used some furnace cement to seal the gaps between the plates of my wood burning stove.
Some of the old cement had deteriorated.

This particular cement came in a small plastic tub and is like black sticky pudding.

How long should I allow it to dry?

The container says to allow a minimum of 4 hours.
However, after 4 hours, I find that the cement is still soft.
Need I wait until it the cement is hard before I fire up the stove?
The last time I used this cement it took about 24 hours for it to be hard (perhaps the relatively low temperature in the house -- due to the stove being on hold -- had something to do with the long drying time?)

Thanks,
Griz

 

[homefront]

Griz,

Right or wrong, I can only tell you what I did.
After the specified time (roughly), I lit my first break-in fire, at around 250 degrees. The next fire, 3 hrs later was 350, and the next 500. At 500 I heard sizzling, which turned out to be moisture boiling out of a thick spot in the cement. There have been no problems since, and I think some heat is needed to cure it out.