Well, my first attempt at mixing and casting the refractory cement was a total bust. It turns out, upon closer inspection (read the label, what a novel concept), that this type of cement is 'air activated'. I take that to mean that it cures as it dries out.
The bag also mentions that it's not recommended in applications that require more than 1/8" thickness. Seeing that I need about 2" - 3" in places this will not do (not to mention that the small foundry-in a-coffee-cup mould that I made is still soft and wet). It would appear that that much refractory cement will take 3 - 4 years to cure.
So on to experiment 2: I went out and bought a whopping big bag of portland cement - a 100lb bag - try and find smaller amounts, go on, I dare you (at least it only cost $9) to mix the refractory and perlite with.
I dug through my recycling box and came up with a large fruit can to use as the main body (so I've gone from a foundry-in-a-coffee-can to a foundry-in-a-fruit-can), a tuna can to use to cast the lid, and an empty shampoo bottle for the inside of the mould (my daughter's, I'm bald as a cue ball). The length of steel tubing is for the burner.
I thought about what I should do for a mix and came up with 30% portland cement, 30% refractory 'cement' and 30% perlite. I mixed the portland cement with the refractory cement and made it wet enough that I could pour in the perlite without the perlite drying the whole mix out completely. I then put the mix into my mould and am going to let it cure overnight:
The little metal tube sticking through the tuna can is the flue for exhaust gasses, and I thought I'd try some copper wire as an impromtu handle. More to come tomorrow *fingers crossed*.