Author Topic: Phosphoric Acid  (Read 18397 times)

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Offline Faol

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Re: Phosphoric Acid
« Reply #25 on: September 09, 2011, 05:59:18 pm »
Just because I've seen acid splash scars, please remember always add acid to water - not water to acid.

Offline lucky

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Re: Phosphoric Acid
« Reply #26 on: August 16, 2012, 10:40:24 am »
Any suggestions on a good place to pick up Phosphoric Acid in the Chicago area?

You can get it at any West Marine boating store. It is called Metal Prep.

You can also get at Home Depot in the paint dept. but do not ask for Phosphoric acid. The employees will just say they do not have it.

It is paint prep and it looks green like anti freeze.
It is called Klean Strip Prep and Etch.

Offline SCRob

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Re: Phosphoric Acid
« Reply #27 on: November 16, 2012, 02:27:09 pm »
So I've been debating on what method to use to attack my rust problems on some misc chromed parts on my bike.  I've narrowed it down to three options:

1. Electrolysis - great YouTube vid, if you're not sure how this works
Rust removal by Electrolysis - Removing rust from a Briggs and Stratton engine shroud

2. Apple Cider Vinegar
Amazing Rust Removal with Apple Cider Vinegar

3. Phosphoric Acid - described well in this thread

I think Electrolysis might be the most effective, based on what I'm seeing and reading.  But I'm also seeing that it will negatively effect or might strip chrome parts.  Can anyone confirm this?

I'd also much prefer to work with Apple Cider Vinegar over Phosphoric Acid due to the toxicity associated with the acid (I've got small kids running around).   But again, I'm unsure how the vinegar will treat the chrome.  Anyone try this on chrome?

Phosphoric acid is the only product I've found that (based on this thread) that I can confirm will not damage the chrome, but has the toxic downside.

Also, does anyone have a recommended sealing agent for chrome to avoid flash rust?  One of the products reviewed in this last pair of YouTube videos might work, but again they're not used on chrome.  Thanks,


Longterm Rust Test
Longterm Rust 1 Year Update

Offline faux fiddy

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Re: Phosphoric Acid
« Reply #28 on: February 07, 2013, 05:59:53 pm »
I used stuff called "crud cutter"   a prepaint phosphoric acid stuff that comes in a spray bottle and has a jelly like texture to help it not run off.

I put it on the scrambler fender, scrubbed and reapplied  and  then just let it dry.  I have a better  spare that came with the bike, so if it  has catastrophic results I'm covered. Seems the rust is cleaned up and I figure the residue can stay there until it sees rain again. I can tolerate cloudy looking chrome more easily  than the rust freckles.

Might revive this thread when I get out in another cloudburst or wash it off.
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Offline SCRob

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Re: Phosphoric Acid
« Reply #29 on: April 15, 2013, 03:59:56 pm »
I stumbled on this stuff called "Metal Rescue" that seems almost too good to be true.  Non-toxic enough to pour out in your lawn, but removes rust from all surfaces w/out damage to other parts like plastic, rubber or chrome.  I haven't taken the plunge yet, but it looks like the ideal product:

Offline m00ntan

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Re: Phosphoric Acid
« Reply #30 on: April 26, 2013, 08:43:01 pm »

I use phosphoric acid. 

One trick from “Must for the Rust” is to let it to let it air dry to avoid flash rust.  Just buff out the white crystals. 

It’s the same acid in vinegar, ketchup. cola, and a lot of other things you eat.  It’s not as caustic as other acids.  The chrome polish you use is phosphoric acid.  Treat it like oil and gasoline, wash it off

It will melt aluminum.  If you leave the petcock on the tank, you’ll need a new one. 

It will not damage chrome, the damage was there before you started.  Hardware comes clean, but dull and gray.