- yarm stockton on tees
place some ingots round the crucible top in furnace and they can be pre heating while the metal inside is melting then just pop a few in till full
Have you tried Carbon Dioxide sand casting?So I've done 10+ melts now, I'm on my second 19kg propane bottle and I still haven't achieved what I set out to do.
The end of the tube inside the foundry has all but disappeared now and the end of the burner itself is taking a bit of a beating.
The refractory is starting to degrade a bit too though is still holding together.
Through a combination of degassing, fluxing and adding boron nitride I get material that has a reasonably tight grain structure and only the tiniest speckles of porosity. It doesn't machine particularly well bit with high SFM and a light cut it can be acceptable. I am exclusively using alloy wheels at the moment.
My biggest hurdle is casting a blank for my gear, I need a disc that is 240mm x 25mm to give room for cleanup. My crucible only holds just enough to achieve this.
I have tried 6 times to make this and each has been a failure of some description though came very close this week, just 1mm too small.
My two most dramatic failures are when there is too much moisture present in the sand and it turns into a bubbling mess of molten aluminium. I've tried drying the sand with the burner before pouring which is hit and miss.
Ideally I need some sort of steel form that will give me a perfect blank, if I had steel that big though I'd just make the damn gear from steel...
Have you tried Carbon Dioxide sand casting?
You add sodium silicate to your dry sand, pack it round the pattern as you would do with a green sand casting then inject carbon dioxide into the mould, this bonds the sand together.
You have no worries about moisture in the sand then.