On Dec 10, 1:02 pm, Jim Wilkins wrote:
On Dec 10, 3:41 pm, "Ken S. Tucker" wrote:

...
A good cast iron is pretty tough stuff, better than malleable at
high temps I'm told.
Ken-

Good idea, but it's so heavy we'd have to remove some of the cannons.

Well ok, but I'm searching for experience, such as fire bricks.
One can have fire-bricks with anthracite coal, burning air fed
that stand up ok. Firebrick is fairly light and cheap.
I guess they can be cast in bound sections.
Ken