Starret Scale - rust removal method?

bcall2043

bcall2043

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I was a good guy this morning and took the wife out for a walk and we ended up at a flea market. I found a Starrett 6" machinist scale model C636EM. I looks handy, having both inch and metric scales. Since it had some rust I was able to get it for a dollar. Now the question is how do you remove the rust without hurting the chrome plating?

I am somewhat familiar with the electrical method and Evapo-Rust chemical method. Rust pits left after clean-up don't bother me. I just want to stop the rusting process and remove the gross rust stains without doing additional damage to the scale markings.

A couple of photos are attached showing the current condition.

Sometimes it pays to be nice to the wife!

Benny

Scale Starrett C636EM.JPG Scale Starrett C636EM - Rust.jpg
 
Benny, are you sure it is chrome plated? Most, quality, steel rules are hardened stainless, with a satin finish. I imagine that the rust is deposits on the rule and then stored in that case. Probably etched into the surface. Gentle work with a scourer and oil might clean them up without putting to much of a polish on the rest of the surface.

Cheers Phil
 
12bolts said:
Benny, are you sure it is chrome plated? Most.........rules are hardened stainless, with a satin finish. ..........
Cheers Phil
Click to expand...

Good point Phil. I don't know but it looks like satin chrome to me. I will take a closer look and will also try and look specs. up in a Starrett catalog.

I just hate to see an old American made tool go to waste or loose effectiveness.

Benny
 
Four ought (0000) steel wool should do the job. You might add a little oil but that is not really necessary as the steel wool has a small amount of oil already.
Joe
 
If you want to do no damage to it try a "magic eraser" it's got the bald guy on the package and works perfectly. leaves all the spots that have been worn smooth from decades of use but gets the crud off without hurting the history.

Steve
 
That is a Satin Chrome finish, and anything manual you do will leave "shiny" spots where you rub it. Then you may as well polish the entire thing to make it uniform. You can use any of the traditional methods of chemical rust removal with no harm to the chrome as long as you don't rub it with anything abrasive.

True, most scales are hardened tool steel, but that one is plated with a semi-mat or satin finish.
 
Thanks to everyone for the replys.

Tony Wells said:
That is a Satin Chrome finish, and anything manual you do will leave "shiny" spots where you rub it. Then you may as well polish the entire thing to make it uniform. You can use any of the traditional methods of chemical rust removal with no harm to the chrome as long as you don't rub it with anything abrasive.

True, most scales are hardened tool steel, but that one is plated with a semi-mat or satin finish.
Click to expand...

Tony,
Thanks for the specs. I don't want to do any more harm than what has already been done. I am afraid the chemical cleaning might take the lettering off and mechanical cleaning would mess up the finish as you noted. I wonder if the electrolsis method would remove just the red rust and leave everything else alone. Has anyone tried this method on a scale or similiar tool?

Benny
 
Since electrolysis is the reverse process from electroplating, I'd be hesitant to use it. I would think a chemical only process more likely to yield acceptable results. Why not try molasses? Or Prep-n-Prime?
 
As Tony said, any mechanical method will change the appearance of the satin chrome. A phosphoric acid based etch will remove the rust without doing further harm. Auto paint stores will carry it or just get a bottle of Naval Jelly at the hardware store.

Tom
 
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