P: Restoration Part 1. DIY Polishing&Engrave for Crankset

Hei!

…Mina opiskelen suomea, mutta edelleen vaikea puhua ja kirjotaa.
So, hope you guys understand me to write in English. :wink:

I would like to share the progression of the restoration for my DA 7700 crankset and DIY stickers for frame.


I got a used condition DA7700 crank from eBay and It has got too many surface damages and the logo as it has been serving to transmit the power of rider’s leg for such a long time.

The way to restore the logo would have simply been to respray on the stencil. but It will has clear limitations. then, I accidentally found a Youtube video that introduces the way of engraving on the aluminum surface, so-called “Electric Etching”. And noticed that it can actually be done with 2 of 9V batteries.

First, I made the “Vinyl” logo stencil sticker based on the measurement of the original logo with Vector editor.

After clear up the surface with sandpaper and alcohol(off the grease or grime…) Printout through cutting plotter put it on the desired area.

Preps :
Masking all the area.
Put a quite much salt (the salt particle can still see under the water) into warm water.
Connect two 9V batteries like below photo.
Red to + to paper clip (or any of object that electrifies) that contacts the crankarm.
Black to - to steel bolt (or any of object that electrifies) that contacts to the saltwater.

Once it connects properly, You will see the bubbles on the steel bolt.

Depends on the desired engraving surface, it will take up to 4~ 6mins.


Linse the surface with tap water to prevent the etching is continuing.

After that, move on to polishing with sandpaper 600-800-2000 grits and applied the compounds.
If you want to add some color, you can use your gf’s nail polish. :wink:
I colored only on the non-drive side arm.

and the final result is…

!

See ya on Restoration Part 2!

49 Likes

nice!

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Very nice!

Heti tuli kyllä mieleen @niq

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proper good

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Nice :sunglasses:

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Fuck yeah

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Lord in heavens!

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Very nice work!

But the 80’s and rednecks wordlwide are currently fighting over who wants their attitudes back more…

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Insane! So cool!

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Looks so good!! Did you polish by hand or do you have a machine for that?

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Thanks! Yeap hand polish for 3hour straight :sweat_smile::sweat_smile:

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Wow, super nice work!

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Very cool process but it’s not really a restoration in my opinion because it’s now polished and the original finish was a clear anodized coating.

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Wooow. Just wow

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This is so good

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Nice!

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Wow

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Hot stuff. I think in Espoo you can use a public laser engraver at one of the libraries.

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I’ve used a similar technique to etch volume markings to a large stainless kettle. Instead of submerging the whole thing in liquid, I attached the negative lead to a cotton swab which I repeatedly dipped into some vinegar with salt in it and rubbed the masked area with it. The result is probably not as even as your process, but good enough and much easier with a larger piece.

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