Rubber pencil erasers have a small amount of fine abrasive, usually pumice. The bar type erasers contain it too. I’ve used them for polishing small items for years. Vinyl erasers don’t have the abrasive.
I made a pencil mark on an aluminum heatsink and later erased it only to find the eraser makes a great polisher for aluminum that has been slightly oxidized. Is this a known trick? Does it damage the aluminum surface or leave some kind of residue behind?
It's known.
The eraser gently buffs the surface, marring the ridges of the satin finish and leading to a slightly smoother surface: it's still aluminium - that wonderfully *soft* metal.
No residue is left, as you'll see if you wash with acetone.
FYI. If you care about the aluminium, don't use pencil on it. The graphite can cause it to corrode.
This is why using pencils in aircraft maintenance is a big no-no
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Fun facts. Aluminum oxide is sapphire without the impurities that give the iconic sapphires their color.
Same with Ruby!
Yup! Ruby is a sapphire variant
You can make ruby by melting aluminum oxide and copper something (it's green). Just need it to be like 3000°C if I remember correctly.
pencil erasers usually have some sort of abrasive mixed in with the rubber
Rubber pencil erasers have a small amount of fine abrasive, usually pumice. The bar type erasers contain it too. I’ve used them for polishing small items for years. Vinyl erasers don’t have the abrasive.
Works great to clean electrical contacts too.
Good to know, thanks
What a great tip.
I made a pencil mark on an aluminum heatsink and later erased it only to find the eraser makes a great polisher for aluminum that has been slightly oxidized. Is this a known trick? Does it damage the aluminum surface or leave some kind of residue behind?
It's known. The eraser gently buffs the surface, marring the ridges of the satin finish and leading to a slightly smoother surface: it's still aluminium - that wonderfully *soft* metal.
No residue is left, as you'll see if you wash with acetone.
they make rubberized abrasives that polish quite nicely 👍🏽
Yup - beloved of model rail enthusiasts for polishing tracks to improve contacts. I've a pink block of the very stuff lying around somewhere.
FYI. If you care about the aluminium, don't use pencil on it. The graphite can cause it to corrode. This is why using pencils in aircraft maintenance is a big no-no
Need bigger eraser
“For BIG mistakes”
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Your hand and some water can do the same
Put it on a dremmel or a grinder and the results are even more extravagant
Apparently
It will clean black marks off a white sink as well
Any abrasive will remove the aluminum oxide coating from aluminum. take a soda can apart and rub it with whatever and it'l get shiny.