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removing gummed up aluminum from cutting tools

empower

Titanium
Joined
Sep 8, 2018
Location
Novi, MI
i've heard of people using CLR to removed gummed up material.
anyone ever done it? whats the general process like?
 
Some folk use lye (sodium hydroxide) for that, but I usually just use a pick. Those that use lye often just loosen the alu with the chemical, then pick it off anyway. Naturally, its best to prevent build-up in the first place by using coolant/cutting lube, etc.
 
Draino is lye with aluminum chips mixed in. Add water and the aluminum reacts fast as it neutrilaizes the lye. So an overnight soak in draino is not going to do much after 15 minutes. Overnight in lye water will keep reacting until all the aluminum is gone or the lye is all used up.
Do not do this in plastic tubs or glass that can not stand the heat.
Bill D
 
Of course lye can eat your skin, clothes and eyes if spilled or boiled into contact. It will not affect concrete but wood and paper will be eaten alive.
No idea about cutter brazing or special coatings?
Bill D
 
I would stay far away from HCl. It reacts with the steel also. The worst part is hydrogen embrittlement. You won’t know it’s there till your tool snaps the next time you use it. Hydrogen in the acid will migrate into the iron matrix of your tool causing enormous localized stresses.
Can be cured though. Just heat in an oven @350°F for an hour and the hydrogen will migrate out of the tool.
 
I would stay far away from HCl. It reacts with the steel also. The worst part is hydrogen embrittlement. You won’t know it’s there till your tool snaps the next time you use it. Hydrogen in the acid will migrate into the iron matrix of your tool causing enormous localized stresses.
Can be cured though. Just heat in an oven @350°F for an hour and the hydrogen will migrate out of the tool.
steel? who cares, i'm using it on carbide tools
 
Phosphoric acid is much nicer to work with.
Some toilet bowl cleaners have it. Concentration is low here so plan on 24 hours or more.
In high con it will attack HSS if left more that 2 minutes. Carbide not a problem, days.
Since it cleans so nice an employee's son once put a Holley carb in the cleaner and went to lunch with her.
Guess what was left after an hour.

We used to recycle AL cutting carbide inserts back to the plants with a one-two-four hour wash using this in the ultrasonics and a inspection for any edge chips.
50% or better still good as new.
Check the edges with a microscope after cleaning.
I buy it from Haviland in Grand Rapids as "Rust and scale remover 138 and 139". Unsure how small of volume they sell.
Bob
 
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Take care when picking off built up edges. Carbide is no good under tensile loads, if it's a sharp edge and you push in the wrong direction the edge will chip off.
 
Draino is lye with aluminum chips mixed in. Add water and the aluminum reacts fast as it neutrilaizes the lye. So an overnight soak in draino is not going to do much after 15 minutes. Overnight in lye water will keep reacting until all the aluminum is gone or the lye is all used up.
Do not do this in plastic tubs or glass that can not stand the heat.
Bill D
Alkali will attack the aluminum. Acid will attack steel.
 
Lye works really well, and is readily available in bulk from you local farm store. Dissolving 100% of the aluminum is preferable to picking away at it for fear or chipping an edge.
I never looked for HCL so maybe that's just as easy to come by.
Lye is also good for stripping anodized parts, just don't leave them too long... I left a small bracket to strip and got distracted talking to a neighbor, came back half an hour later and couldn't find the bracket anymore!
 








 
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