Today I received by mail 2 new crucibles for my furnace, so I tried a melt of brass.
The source of the brass was machining offcuts, machining failures (quite a few of them), and machining swarf. The swarf was not very clean, probably containing some aluminium, cutting oil, dirt and grunge.
It was an interesting experience.
Firstly, the temperature had to increase to 1000ºc. Later increased to 1050ºc. It is very hot. And the impurities came off as smelly fumes, and dross.
But, I poured some ingots.
And I made another remelt. And later remembered something which I had read somewhere….. molten metal and water is dangerous.
After making a few brass ingots, and quenching the moulds so I could remove the ingots, I proceeded to another brass melt.
When I poured the molten brass into the mould, IT EXPLODED!
I had caused a steam explosion. Probably the mould was still damp. And when the molten brass entered the mould, it EXPLODED. I kid you not. It went BANG. Luckily, none hit me, but some of the molten brass had landed up to 2 meters away.
OK. Lesson learned. Molten metal must be treated carefully, with respect. And NEVER put it in a container which is not thoroughly dry.
And after inspecting those brass ingots, I will never try to melt dirty brass, or any other dirty metals.
Meanwhile, preparing for another aluminium pour.
Here is the next tree. You might note that there is a spaghetti appearance of wax tubes added to the tree, to allow efflux of air from the cavities, as the melt enter them.
Next aluminium pour on Thursday. Fingers crossed. Stay tuned.