Removing "smeared" aluminum from CNC mill window.

[Machinerer]

I'm doing some pretty heavy aluminum roughing on an HMC. The chips blasting the window has caused the aluminum to kind of smear, or gall on the window. I thought it was getting scratched, or frosted at first, but it's definitely built up aluminum.

Any suggestions for removing this? I've tried scotch brite, and simichrome, which did have an effect, but it would take forever to get the job done.

 

[Digital Factory]

Is your window layered with safety glass on the inside and plexiglass on the outside, or all plexiglass?

If it's safety glass on the inside, you can go more aggressive with solvents. Acetone would be worth a shot.

 

[SeikiCorp]

A soft cloth with a little Brasso cleaner works good on glass and plastic.

 

[hi-fly-cnc]

Not helpful at the moment, but once you got it clean again: all the cool kids are putting Tesla screen protectors on the inside... They are reasonably cheap, glass and have an oleophobic coating on them...

 

[jmkasunich]

Aluminum reacts with both strong bases such as sodium hydroxide (lye) and with strong acids such as hydrochloric (muriatic) acid. Organic solvents like acetone, mek, etc., are less effective against metals and more likely to attack other organic substances like paint, plastics, etc.

 

[Machinerer]

Is your window layered with safety glass on the inside and plexiglass on the outside, or all plexiglass?

If it's safety glass on the inside, you can go more aggressive with solvents. Acetone would be worth a shot.

I believe its 2 panes of real glass. Inside is definitely glass.

A soft cloth with a little Brasso cleaner works good on glass and plastic.

I think I have Brasso at home, I'll give that a shot.

Not helpful at the moment, but once you got it clean again: all the cool kids are putting Tesla screen protectors on the inside... They are reasonably cheap, glass and have an oleophobic coating on them...

That's interesting. Is it the tempered glass ones, or plastic ones? I can't imagine either holding up when getting pelted with chips.

Aluminum reacts with both strong bases such as sodium hydroxide (lye) and with strong acids such as hydrochloric (muriatic) acid. Organic solvents like acetone, mek, etc., are less effective against metals and more likely to attack other organic substances like paint, plastics, etc.

And both of those would be safe for the glass? (Lye and MA?)

 

[plastikdreams]

Hcl is fine with glass, naoh not so much.

 

[Scruffy887]

Oven cleaner applied very carefully? Do not spray a blanket coating on everything.

 

[CarbideBob]

Some toilet bowl cleaners are phosphoric acid based. They love to remove aluminum.
Weird and but no so fast acting is Coca-cola. Yes the stuff you drink. Check the label.

 

[Ryan at Sparrow]

We have used pumice stones with varying degrees of success. It still takes ages and you have to do it in a way that you aren't scratching the glass, but it is possible. I've been wanting to try steel wool but have never had any on hand when I'm cleaning that stuff off. Maybe pumice stone for "rough" cleaning and then steel wool once a good bit is off for a "finish". Service techs have told me steel wool is the preferred method.

 

[Mud]

Service techs have told me steel wool is the preferred method.

OOOO steel wool works wonders. Also try the kitchen scrubbers that look like a handful of stainless steel drill chips available at the Dollar Tree or a grocery store.

 

[Machinerer]

Tried Vanisol (High Acid Toilet Bowl Cleaner) since I know it'll clean aluminum out of the flutes of a cutting tool. It didn't seem to work, but I was also afraid to let it sit for any length of time, on a fairly new $1M machine. I'll try the steel wool tomorrow. I use that on my car windows, and have some at home. Didn't even think of that.