Eddie,
Haven't heard of AlloyAvenue, will give it a try. A mate of mine has posted a number of videos on youtube as luckygen1001, they are very good, his furnace and mine are the same except he runs his on pressurised waste oil. Ceramic fibre , Zircon paint ,XR136 silicon carbide plinth and crucibles from Refractory and Ceramic, 50 Geddes St ,Mulgrave VIC 3170. 03 9560 4477, the man to speak to is John Govan, manager. He is quite happy to help out backyarders which I find is very rare. My furnace outer is the shell of a HWS, as you mentioned. I tack welded this to a piece of 6mm steel plate, put it on wheels and made a base about 2 to 3 inches thick of castable refractory as the floor, trowel flat. Castable rated to 1350degrees C is OK as it will be protected by 2 thicknesses of ceramic fibre.Ceramic fibre CFB25H, 25mm thick is rated to 1400 degrees C, this is why you need the zircon paint, to raise the rated temp a bit and it serves to protect the fibre as well. Cut fibre into lengths to line the inside of the HWS. Four vertical rings, one inside the other, stagger the joints. Sodium silicate works as a high temp glue. Place XR136 plinth on floor in centre, cut two rings, one on top of the other, to fit between plinth and outer wall, make it a neat fit . For the tuyere I used a small amount of castable refractory, cut away a bit of the fibre surrounding the entry, drill and tap a few holes for 6mm bolts to act as anchors and dovetail the refractory. You could do this before you line the furnace with the blanket, mine was retrofit through necessity!. Cut a circle to fit on top of the fibre lining to act as a seal, glue with sodium silicate (waterglas), paint all interior except top of seal and plinth with zircon paint so no bare fibre shows. The lid was packed radially with fibre strips, make it about 100mm thick and pack real tight ,then poke some 6mm rods through the outer shell and fibre to stop it from dropping. Paint all surfaces of fibre with zircon.
There is another product called J Cote, it is a heat resistant paint as well but is more expensive and doesn't work any better.
Approx costs: Ceramic fibre , 1 box=1 furnace+$110
Zircon paint , about $70 will last for years
XR136 plinth, about $40
Densecrete 135F 25kg $40
Now that I have the two furnaces to compare, I would not bother with The Artful Bodgers, the one described above works brilliantly, clean and easy with gas and if you want cheap, use pressurised waste oil(messy). Easy to make, easy to repair.
Whereabouts are you in Australia?
Hope this helps.
Regards
Graeme