Given the price of Aluminium in large pieces and the problems with shipping I decided to build a cheap “flowerpot” / “coffeecan” furnace from scrap and cheap materials to do some simple casting which could then be machined.
Everyone on the forums recommended getting a ready made crucible and also some lifting tongs made to fit those. The Silicon Carbide crucibles can take being heated or cooled faster (thermal shock) than the Clay/Graphite ones and hence it is suggested that these are better for beginners. Looking at the shape and capacity an A3 crucible looked the best for my requirements.
I made some investigations and found two suppliers in the UK who could provide both components. (there’s more in the US but shipping is expensive).
A3 crucible: £22.72
F6 lift out tongs: £137.66
A3 crucible: £25.00
F2 crucible carrier: £87.64
A3 crucible: £16.85
Crucible tongs upto 25KG: £78.65
Total: £95.5 + P&P + Vat
I also have a third supplier who came in about the same prices. The price of crucibles I ok with. The tongs are however rather expensive. I appreciate that the crucible lifting tongs are made on demand and that it does require a skilled blacksmith to make them and they are specially design to avoid damage to the crucible. However given that I may be only using them 3 or 4 times a year I could get through a lot of crucible before these tongs are economic. I won’t be buying at these prices unless I get to the point where I’m doing casting every week. So I’ve decided to buy some tongs / fire irons from eBay and see if I can adapt them to my requirements. I’ve also just discovered that A3/0 is a tiny little cruicible and not to be mistaken for A3 which has a capacity of approx 470ml.
My other problem is finding some refractory clay and/or mortar in a bag smaller than 25Kg, but Wickes looks like a possible with it’s 2Kg bags and 5Kg tubs of mortar with the quick drying amusingly taking longer to dry than the general purpose…
I’ve also just found Hindleys who sell crucibles but I need to check what materials these are made from.