End mill all gummed up? (Chemical Aluminium removal)

During my initial attempts to cut aluminium I managed to gum up a couple of end mills.
I have also gummed up some regular drill bits when drilling out aluminium with a drill.

Removing aluminium the easy way:

I have used regular caustic soda granulas (a table spoon worth) dissolved in in a few oz of water and placed the gummed up bit into the solution. Left it over night immersed and removed it the following day, all fresh and shiny like new :slight_smile:
Only aluminium will be dissolved, steel and other metals will be unaffected.

This is not something I can credit for, its not news but with many newcomers one might not know all the tricks yet… :slight_smile:

Disclaimer: Caustic soda creates heat, can cause severe chemical skin burns and must be handled with great care, good ventilation is a must.


Rubber gloves and eye protection would be a good idea too.

Nice info!

Thanks for the tip.

Will it affect the bit coating?

I may be wrong but I dont think caustic soda granules would get hot enough to kill the tempering of treated steel. The chance of chemical burns definitely exists, but this would not be the same as a thermal (heat) related burn.