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Aluminum smears on granite, how to remove?

partsproduction

Titanium
Joined
Aug 22, 2011
Location
Oregon coast
Hi,
I was doing layout work on the surface plate on a 3 1/2 X 6 1/4 X 11 1/4" 7075 block, not thinking about the aluminum streaks on the granite plate until too late.
I know drain cleaners (sodium hydroxide) mixed with in a strong solution will make the bright smears to disappear but I'm concerned about the granite of the plate. This is a black granite plate if it makes a difference.
Thanks, for any help.
parts
 

Demon69

Titanium
Joined
Mar 3, 2013
Location
Area 69.
Hi,
I was doing layout work on the surface plate on a 3 1/2 X 6 1/4 X 11 1/4" 7075 block, not thinking about the aluminum streaks on the granite plate until too late.
I know drain cleaners (sodium hydroxide) mixed with in a strong solution will make the bright smears to disappear but I'm concerned about the granite of the plate. This is a black granite plate if it makes a difference.
Thanks, for any help.
parts

At the risk of being controversial, a sizable flat soft white aluminium oxide stone lubed with mineral spirits, floats over the surface and wipes of metal smears and doesn't touch the granite. You can really feel it catch anything that's standing proud.
 

boslab

Titanium
Joined
Jan 6, 2007
Location
wales.uk
Avoid chemicals, standrige granite site or contact them, it’s easy to make a headstone out of a granite plate
Mark
 

jhov

Aluminum
Joined
Jun 5, 2020
At the risk of being controversial, a sizable flat soft white aluminium oxide stone lubed with mineral spirits, floats over the surface and wipes of metal smears and doesn't touch the granite. You can really feel it catch anything that's standing proud.

Is this controversial? Precision ground flat stones are perfect for removing raised material from flat surfaces.
 

Larry Dickman

Titanium
Joined
Jan 30, 2014
Location
Temecula, Ca
Angle grinder with a diamond blade will work.

Or, I have found the streaks just disappear on their own.
I like to work on a 2 4 6 block to avoid wear/smudging the plate.
 

Demon69

Titanium
Joined
Mar 3, 2013
Location
Area 69.
Is this controversial? Precision ground flat stones are perfect for removing raised material from flat surfaces.

Controversial in the sense of using abrasives around a granite flat.
Ime, aluminium oxide doesn't touch granite at all, silicon carbide will cut for a short while before dulling off, diamond cut's granite like butter.
The stone doesn't have to be 'Robin' flat, I kept mine clean and flat to a fashion on cast iron lap impregnated with diamond.
The main bit is the AO stone will cut deposits of material without cutting granite.
 

partsproduction

Titanium
Joined
Aug 22, 2011
Location
Oregon coast
Thanks for all responses.
I did send a question to A.Ottavino corporation about lye to clean surface plates (And why) but I have to say, the website showed only granite for buildings and monuments with a the exception of one small area that showed a surface plate magazine ad looking to be from around WW2.
So I wonder if they still make plates.

PS the aluminum smears don't stand above the surface, if at all it would seem micron size heights. It just makes white colored streaks so it's probably as thick as a pencil mark.
 

edwin dirnbeck

Hot Rolled
Joined
Oct 24, 2013
Location
st,louis mo
Hi,
I was doing layout work on the surface plate on a 3 1/2 X 6 1/4 X 11 1/4" 7075 block, not thinking about the aluminum streaks on the granite plate until too late.
I know drain cleaners (sodium hydroxide) mixed with in a strong solution will make the bright smears to disappear but I'm concerned about the granite of the plate. This is a black granite plate if it makes a difference.
Thanks, for any help.
parts

Unless you borrowed some ones plate plate and are embarrassed,FORGETABOUTIT. Unless you are working in a temp. controlled shop really really holding .0001 tolerances EVERY DAY ,your surface plate ,will be good for your lifetime Edwin Dirnbeck
 

edwin dirnbeck

Hot Rolled
Joined
Oct 24, 2013
Location
st,louis mo
Hi,
I was doing layout work on the surface plate on a 3 1/2 X 6 1/4 X 11 1/4" 7075 block, not thinking about the aluminum streaks on the granite plate until too late.
I know drain cleaners (sodium hydroxide) mixed with in a strong solution will make the bright smears to disappear but I'm concerned about the granite of the plate. This is a black granite plate if it makes a difference.
Thanks, for any help.
parts

Unless you borrowed some ones plate plate and are embarrassed,FORGETABOUTIT. Unless you are working in a temp. controlled shop really really holding .0001 tolerances EVERY DAY ,your surface plate ,will be good for your lifetime Edwin Dirnbeck
 

Bill D

Diamond
Joined
Apr 1, 2004
Location
Modesto, CA USA
Use lye and some water, not drain cleaner. A slower, safer reaction. Still wear goggles and gloves.
Drain cleaner is lye with Aluminum chips. The Al is to impress the user. All it does is react with the lye, thus neutralizing it, this causes the mix to get hotter. dangerously hot, possibly a steaming blow up into your face. This reaction uses up the lye before it can react much with the grease and hair causing the problem. Then you have to buy more. It will not continue to work overnight since the lye has all reacted with the AL.
Pure lye and water will slowly react with the problem stuff until it is all reacted or the bad stuff is all gone.
Bill D
 

Eric M

Cast Iron
Joined
Nov 21, 2007
Location
Orlando, FL
Scotchbrite pads (or the like) worked for me in the past. Followed up with Starrett surface plate cleaner. Never had an issue when the plates were calibrated.
 








 
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