Corrosion cleanup yet again
Posted: Mon May 14, 2018 3:44 am
Tyler Meagher's encrusted vacuum pump restoration deserves a round of applause.
Not so my electromagnet "starter plates", which got ugly because of my own negligence during years of storage. Paint scraper, Scotchbrite, steel wool, WD-40 (dribbled from an aerosol can that'd lost its pressure), and lots of elbow grease restored the surface to reasonable flatness. I think the original rust-resistant plating is tin. Magnetic flux joint surfaces don't benefit from a thin layer of tin, but it's much better than an irregular layer of pittium.
Now a question for the forum.
The cleanup exercise brought to mind the old Navy aphorism: "If it doesn't move, paint it." This weekend I spent more time degreasing steel than removing corrosion products. What are good ways to do that at home?
Recently machined parts were oily, from fluids like Tap Magic. Most of it came off with lacquer thinner, citrus degreaser, acetone, or camp stove gasoline. It's not practical or safe to use those materials in a bath, or a hose-end sprayer. I swabbed around with a small, very "wet" paper napkin or towel, followed immediately by dry napkin to soak up oily solvent. But there seemed to always be some residual oil being pushed around. Happier in contact with steel than with paper? A squirt of aerosol "flux remover" made a puddle that expanded rapidly -- eager to wet the steel -- with its edge pushing a visible ring of oily liquid that had fine particles in it. Still not well picked up with a dry napkin. Do solvents need to drip off from the workpiece to carry away the last oil and grease?
On the smooth tin-plated parts I tried a more aqueous approach, but might have made things worse. Started with creamy lanolin-filled hand cleaner, rubbed around with a plastic dish scrubber and then hosed off with water outdoors. Maybe it was the lanolin that left the surface hydrophobic. Tried to take that off with liquid dishwashing detergent and more hosing with water. Never got to the point where the aerosol flux remover test didn't show differences between places. What next? Soapy steel wool pad? Steam jet?
Hints welcome! Thanks.
p.s. maybe chemistry alone isn't enough. How about scrubbing with a stiff brush. Toothbrush? Wire brush?
There is a vapor degreaser at work, for circuit boards. But it's filled with thousands of dollars worth of Vertrel or Aerotron solvent -- gone are the TCA and TCE days.
Not so my electromagnet "starter plates", which got ugly because of my own negligence during years of storage. Paint scraper, Scotchbrite, steel wool, WD-40 (dribbled from an aerosol can that'd lost its pressure), and lots of elbow grease restored the surface to reasonable flatness. I think the original rust-resistant plating is tin. Magnetic flux joint surfaces don't benefit from a thin layer of tin, but it's much better than an irregular layer of pittium.
Now a question for the forum.
The cleanup exercise brought to mind the old Navy aphorism: "If it doesn't move, paint it." This weekend I spent more time degreasing steel than removing corrosion products. What are good ways to do that at home?
Recently machined parts were oily, from fluids like Tap Magic. Most of it came off with lacquer thinner, citrus degreaser, acetone, or camp stove gasoline. It's not practical or safe to use those materials in a bath, or a hose-end sprayer. I swabbed around with a small, very "wet" paper napkin or towel, followed immediately by dry napkin to soak up oily solvent. But there seemed to always be some residual oil being pushed around. Happier in contact with steel than with paper? A squirt of aerosol "flux remover" made a puddle that expanded rapidly -- eager to wet the steel -- with its edge pushing a visible ring of oily liquid that had fine particles in it. Still not well picked up with a dry napkin. Do solvents need to drip off from the workpiece to carry away the last oil and grease?
On the smooth tin-plated parts I tried a more aqueous approach, but might have made things worse. Started with creamy lanolin-filled hand cleaner, rubbed around with a plastic dish scrubber and then hosed off with water outdoors. Maybe it was the lanolin that left the surface hydrophobic. Tried to take that off with liquid dishwashing detergent and more hosing with water. Never got to the point where the aerosol flux remover test didn't show differences between places. What next? Soapy steel wool pad? Steam jet?
Hints welcome! Thanks.
p.s. maybe chemistry alone isn't enough. How about scrubbing with a stiff brush. Toothbrush? Wire brush?
There is a vapor degreaser at work, for circuit boards. But it's filled with thousands of dollars worth of Vertrel or Aerotron solvent -- gone are the TCA and TCE days.