[Chris Marriner]

First post here - so I hope that this is in the right place... or at least an acceptable place...

I have a 14" High temp aluimina crucible.
I have it inside a custom - but similar design to an AIM wire melter.
The main lid is 3" brick with an access port door of 2" brick.
The main lid sits on top of the crucible - the thought was to keep the heat in - when opening the port to gather...

I’m guessing that the crucible has some insulating properties… and that when heating – the temp in the firing chamber will likely be different than inside the pot…

For example – I stuck my pyrometer into the air chamber above the pot – and it is about 200-220 degrees (750 degrees) less than the firing chamber (970 degrees)… Presently at 1440 firing - 1250 inside pot...

I assume that at some point this will even out… or should we have left approximately 1/2" for air flow??

Is this temo difference stressing out my pot and risking possible shock??

Is there a point where crucibles basically become just a vessel and transfer heat evenly because it’s lost it’s insulating property??

As it's heating up... I've got a lot of time to wonder about all these questions...!!!

THANKS!!