What kind of refractory coating should i use for a steel crucible when i want to melt aluminium ? And what kind of flux should i use ?
At the very least, let the steel get a bit rusty then stick it in the furnace until it gets red hot. Take it out and let it cool. It will turn black, and that black oxide coating will provide fairly good protection I've seen people mention kiln wash too. I've also seen boron nitride mentioned, that stuff is used to coat ladles and such in professional foundries, I believe. I use a homemade salt flux for aluminum. You take a can of low sodium diet salt (Morton's Lite Salt, Windsor Half-Salt, etc) which is half sodium chloride and half Potassium Chloride (plus trace ingredients that can be ignored). Melt it in your crucible and pour ingots. The resulting eutectic salt alloy works better than just using the stuff straight out of the can (which people also do) because it has a lower melting point. Just crush the ingots and flux your aluminum melts with little bits of that. Make sure whatever you pour the salt into is completely dry by heating it up in the furnace exhaust while the salt is melting. Good luck! Jeff
I think they call it kiln wash. Pottery places should have. Ya know what stops this flaking crap floating around in your melt? One of these>>>>>>>https://www.ebay.com/itm/Salamander...861623&hash=item2eb49a15bb:g:yTcAAOSw~gRV23YT I've used this seller and no problems so far.
Thats a great link to Jets Tools. I've bought all of my crucibles from them. Fair pricing, good packaging, fast shipping. I've bought A10's & A12's. Sitting on new ones right now, waiting for a dry weekend. Tired of waiting.
The Navy Foundry manual calls for whiting (calcium carbonate, chalk dust) mixed with water. 7 lbs whiting to 1 gallon of water. http://archive.hnsa.org/doc/foundry/part4.htm#pg230
