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removing gummed up aluminum from cutting tools

A little information about removing material with acid. You put a part in acid and some comes off but then nothing more happens, no matter how long you let it soak. The reason is because the acid solution can only hold so much of what you are dissolving. Dump the acid and refresh it a couple of times. Cleaned badly iron fouled PVC pipes by doing 6 1 hour soaks. Didn't matter what acid, they all did the same thing. So we used citric since it is very safe.
 
As others have said caustic soda (lye, sodium hydroxide). Add some to a little hot water and dissolve, then dip your tools. You should see the aluminium bubbling immediately, making sure there is no oil on the surface before dipping helps. Rinse it with brake cleaner and dry with compressed air before you dip it usually takes care of that.

If you can agitate it it will speed up the process a bit.

Make sure and wear hand and eye protection.
 
I always have used "The WORKS" Toilet bowl cleaner. Probably HCL, but really easy to use. I drop the endmill back in it's tube and fill it with the WORKS. Spotless cutter in the morning. Saved me a lot of money in cutters over the years.
 
HCL will attack the cobalt binder (the "glue" in cemented carbide cutting tools)
Yes it not fast acting but some grains are likely to fall out leaving a "ratty" edge at 500x and above.
This is why carbide tool makers do not use it for cleaning.
It sure is fast at removing Al buildup.
The care here is not to attack or etch the cobalt base while getting rid of the aluminum up top.
 
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I just left some inserts in some Zep Purple for a week all of the aluminum bits turned into black specs. They came off the inserts. Guess I will see what happened to the inserts after sitting for so long when I use them again on some steel.
 
HCL will attack the cobalt binder (the "glue" in cemented carbide cutting tools)
Yes it not fast acting but some grains are likely to fall out leaving a "ratty" edge at 500x and above.
This is why carbide tool makers do not use it for cleaning.
It sure is fast at removing Al buildup.
The care here is not to attack or etch the cobalt base while getting rid of the aluminum up top.
Any modern CVD/PVD coating would protect against that though right?

I have never had to remove aluminium build up from uncoated carbide anyway. It only really sticks to coatings and sometimes HSS taps and the like
 








 
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