Cleaning crucibles

[jsargent]

Here's a simple one... I have a half dozen scorifiers and crucibles that I would like to remove hardened flux from. The flux is 75% borax and 25% sodium carbonate. No silica or flourspar. Any ideas?

 

[lazersteve]

Dishes can be cleaned with soda ash and heating. Pour off the molten slag and repeat until the dish is clean. This is hard on the dishes so don't over it.

This works best on the white dishes, but I have also used it on the fire clay (brown) ones.

Steve

 

[jsargent]

Dishes can be cleaned with soda ash and heating. Pour off the molten slag and repeat until the dish is clean. This is hard on the dishes so don't over it.

This works best on the white dishes, but I have also used it on the fire clay (brown) ones.

Steve

Thanks Steve... but soda ash residue is part of what I'm trying to remove, along with residual borax. I'm trying to remove the solid coating with a low temperature method to return the crucibles to their flux-free condition. Presumably both borax and soda ash are soluble in water but regular warm water does nothing. I'm trying NaOH in water now and it seems to be working but slowly.

 

[lazersteve]

Use a torch for heating and sprinkle in some fresh dry soda ash.

The fresh molten soda ash will liquefy the slag and allow you work the embedded debris out of the dish. Once the fresh soda ash is saturated with slag, pour it out while it's hot.

Repeat to remove the majority of your contaminated slag (borax, soda ash, and base metals). The dish won't be 100% clean but it will be much better than before. You can reuse these dishes for inquarting or general melting of impure metals.

Steve