My IFB/fibre-blanket furnace build.

With analyzing my whole situation, I have ripping oxygen. I do not have soft oxygen air. My manifold has 2 psi......

So, I think I'm actually pulling a higher intensity burn before the lid.

In my opinion the crucible was sheered with a melting 1.5 inches up with a 2.5 inch plinth. So 4 inches from the bottom of the furnace.

I will now give a salamander a 12 the fruits. We will see how she ventures.

 

To anyone insisting on using SS or mild steel crucibles...
A layer of kiln wash goes a long way to extend their life. The stuff is dirt cheap. You mix it up, slosh it on, dump it out and let it dry.

This is the stuff. No I'm not an affiliate. I've got no time for that BS.
https://www.amazon.com/Fireworks-FW...ld=1&keywords=kiln+wash&qid=1585287976&sr=8-2

 

I had the same experience as Jeff but never explored the issue enough to tell for sure if it burned through from outside or if the hotspot accelerated the aluminum attack from the inside. I never took the time to try a wash either. I just know too much blower=hotspot=puddle. Excessive air will goof up a ceramic crucible too.
Check out Masteryoda's work on AA. After bulk scrapping in his tilting furnace he would pour the metal into a wash-coated milkshake cup and put it into a crucible furnace to flux and/or de-gas before pouring into his ingot trays. He claimed that cup would last many heats using NG. They guy really knew (knows) his numbers regarding cumbustion requirements as well.
According to the Navy Foundry Manual wash can be made with calcium carbonate and water. It is referred to as whiting.

Pete