Restoring Rusty Forks w/Phosphoric Acid Mix

Minimichael

Minimichael

Well-Known Member
#1
#1
You may have seen this elsewhere. I did, and bought a 8oz. bottle of 80% phosphoric acid and mixed in a couple ounces of cheap alcohol sanitizer, sprayed it on and let it dry. You tubers might use a wire brush next, but the scale on mine was a hardened candy coating that scraped off with a razor.

Be careful with this stuff, too. It's acid. Burns your lungs and eyes.

This isn't a how-to video, but it sorta takes you through step one: https://youtube.com/shorts/KaF8OZLyjSw?si=ya0r5OZd_cmiRJ5o
 

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Minimichael

Minimichael

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#4
#4
But before I get to the zinc oxide step, and with the rust more or less out of the way, I did some deburring and brushing and light buffing with abrasives. Here are pics of where I'm at, currently.

I'm surprised to be getting through even more scale and finding even more chrome underneath, by using a series of strips of 180 grit emery cloth, then 400 and 600 sandpapers, and then "0" steel wool.

They're still far from perfect but I believe I'm becoming perfectly happy with them..
 

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Minimichael

Minimichael

Well-Known Member
#6
#6
Next I busted out my automotive buff and polish kit to see where that might take me, and it did a pretty nice job of smoothing the sandpaper scratches and making the tiny rust pits a touch more microscopic to the eye. But you can still see some damage. Anyway, I'm not removing any more of the plating.

Below are some before and after pics I took to track my progress.

Still to come, I add zinc plating to fill in and seal those microscopic pits and channels to protect against future rusting..
 

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Minimichael

Minimichael

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#7
#7
A pic of the forks in daylight reminds me they are what they are (ie: permanently pitted). Still, I've now cleaned and brushed the tubes down with acetone because the final step is sealing up those scratches and pits with a little diy zinc plating, as I understand it.

Once again, I'm using phosphoric acid, but whereas the rust removal phase combined the acid with water or sanitizer (as media to carry the acid into the nooks and crannies to 'kill' the rust), this plating phase incorporates zinc oxide powder.

Note that rather than premix a zinc/acid paste (as one video suggests), I dusted the forks with the oxide - by hand - twisting and rubbing the powder in good. This is because once the acid is introduced, the zinc begins to crystallize and stick to the metal. By putting the zinc powder on first, it's in position already and just waiting to be wetted with the catalyst.

I didn't get many pics from this stage because I'm wearing safety gear like chemical resistant gloves and respirator. Brushing on the acid was tedious and messy as I attempted to not disturb the zinc powder too much. The wet pic does kinda show some spots where flaws in the chrome started blooming into teeny tiny crystal farms.

Btw: BE CAREFUL IF YOU DO THIS. THIS IS INDUSTRIAL ACID. Ventilate, plan ahead and wear safety gear!

Next I'll be finishing with steel wool and presenting final pics.
 

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Minimichael

Minimichael

Well-Known Member
#8
#8
All done, so here are some final before and after pics - following phosphoric acid, sanding, buffing, and zinc treatment.

In review, it was worth it. The phosphoric acid made easier work of the rust. The zinc process may only be leaving me with a false sense of security but it also kept me brushing and buffing all the more. And to be sure, the pits and scratches do look a bit shinier inside, if you look real close.

Thanks for reading.
 

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