Foundry Lining & Crucible

I have recently discovered my foundry can burn through steel whist doing a casting.

I have been using steel crucibles over graphite as I have not been casting structural pieces and do not require a high level of metal purity. I have previously used canisters and containers to melt the aluminium as the melting point is so low (660 celcius) it does not damage the steel (1,500 celcius). I made my latest crucible out of 6mm dark steel and has been very reliable over several firings until now.

During the recent casting I refilled the furnace coal half way to melt for longer as I had a large ammount of aluminum to cast. Towards the end of the firing the crucible developed a hole and the aluminium dribbled out of the furnace through the air intake pipe.

This means two things, the furnace can get to much higher temperatures required for aluminium. And this is a good occasion to adjust the recipe as I now have to chip out the aluminium from the furnace lining. I will also need to re-consider my crucible material now I know the furnace can reach higher temperatures. I am achieving these temperatures by improving the lining, the foundry is still coal powered.