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Sun Mar 09, 2014 8:04 pm

Phosphoric acid here, like at Home Depot, under the Prep and Etch name is less than $20 a gallon. Great stuff for killing rust

Mon Mar 10, 2014 12:35 am

I found that youtube video about vinegar and was skeptical. But I tried it and it seems to work as well as the phosphoric acid. Treated the metal weeks ago and it's still exposed and there seems to be no change since then.

Wed Mar 12, 2014 9:24 am

I found several de-ruster formulas have sodium bisulfate as their "secret" ingredient, especially older ones that were before the required safety labeling. It is sulfuric acid that becomes active when wet. Usually it comes mixed with a surface disbursent like Triton X-100, a molecule smallen-er.

http://en.wikipedia.org/wiki/Sodium_bisulfate

Wed Apr 29, 2015 4:15 pm

Evapo-Rust uses a chelation agent, most likely EDTA (ethylenediaminetetraacetate). It's synthetically manufactured and many people swallow small amounts for health reasons, but I would not risk it.

Some people swear by citric acid, Apple cider vinegar and molasses for rust removal the natural way.

Wed Apr 29, 2015 4:33 pm

EDTA is also used in dentistry, but we try not to have people swallow too much... So it's relatively safe... No 11 fingered babies reported yet.

The molassas is crazy messy and you'll have sticky sugar weeping out of the seams forever, no matter how much you wash it. Especially on rims like the video on the previous page.

I've had pretty good results with 2 days of apple cider vinegar bath followed by a quick baking soda wash and then acetone wipe before primer. As long as you knock off the big stuff beforehand.

Wed Apr 29, 2015 6:57 pm

I agree on the sticky molassas mess. Don't forget about ants and other insects attracted to it.

Wed Apr 29, 2015 8:57 pm

Vinegar is good and cheap, but it takes longer than the other methods. It smells yummy too :) I like this stuff so much that I thought of making a mini-pool and filling it with Vinegar... CHEAP acid dipping without the need to blast.

Evapo Rust is magic, but it's $10/bottle up here.

Wed Apr 29, 2015 9:22 pm

IIRC Evapo Rust is just citric acid and water (hence the nontoxic you can drink it), I read something about it years ago. People were making "Evapo Rust" themselves.

Wed Apr 29, 2015 9:29 pm

vwnut1 wrote: Evapo-Rust uses a chelation agent, most likely EDTA (ethylenediaminetetraacetate). It's synthetically manufactured and many people swallow small amounts for health reasons, but I would not risk it.

Some people swear by citric acid, Apple cider vinegar and molasses for rust removal the natural way.

I just saw your post, that sounds more plausible but several swore it was just citric acid mixed with water. My memories of it are hazy but I think people were buying the citric acid in large amounts and mixing it themselves for really cheap. I'll try to find where I was reading this years back. I remember something in maybe VW Trends years back about de-rusting bolts with Koolaid packets. :lol: I guess the citric acid came into play there.

Thu Apr 30, 2015 2:26 am

'64cal lookdub wrote: IIRC Evapo Rust is just citric acid and water (hence the nontoxic you can drink it), I read something about it years ago. People were making "Evapo Rust" themselves.

OMG.....Don't drink that mess ](*,) .... you're in the land of Coca Cola, come on now.

Thu Apr 30, 2015 2:47 pm

^^^With that segue... Phosphoric acid is one of Coke's ingredients. Phos acid is my go to for rust removal. Still less than $20/gallon at HD.
The primary ingredients of Coca-Cola syrup include either high fructose corn syrup or sucrose derived from cane sugar, caramel color, caffeine, phosphoric acid, coca extract, lime extract, vanilla, and glycerin.[citation needed] High fructose corn syrup or sucrose are overwhelmingly the major added ingredients: one 600 ml bottle (≈20.29 U.S. fl. oz.) of Coca Cola contains the approximate equivalent of 15 teaspoons of sugar.[1] However, contrary to what is implied by the "cola" name, Coca-Cola syrup does not contain any kola nut extract.[2] Since no kola extracts are present in the recipe, the primary taste of Coca-Cola comes from vanilla and cinnamon with trace amounts of orange, lime and lemon and spices such as nutmeg.[3]

Fri May 01, 2015 10:45 am

I use Miuratic acid to remove stubborn rust when mechanical removal is not practical or possible. You have to be extremely careful with fumes and splatter.

When cleaning wheels I found it most time/cost effective to have them sand blasted.

Thu Oct 13, 2016 3:14 pm

This wide fan was severely rusty and would have created too much resistance if used in that condition.

One quart of hardware store Ospho (phosphoric acid) in an oil change pan with water added to cover the fan. The mix ended up about 3 parts water to one part Ospho. Let it soak 48 hours and rinse with water. No scrubbing or touching was necessary.

Blades before and after.

Fri Oct 14, 2016 12:40 am

Phosporic works great on surface rust. I sprayed the whole underside of my truck with a diluted mix.

This was orangey-grey with rust before spraying. Most is light grey and rust-free now...

Needs a scrub to take off some of the the black deposits as there is some thicker surface rust still under there. I'll treat those spots again directly with a brush then use a clear underbody wax.

Strange thing though - none of the floor pan under the drivers' cab area has turned grey. It's gone a redish-bronze colour. No powdery rust deposits though. I wonder if it was treated with something before?

Fri Oct 14, 2016 6:12 am

How does paint react to the metal after treating it with phosphoric? Do you need to do anything other than rinse with water?

I've had great luck with Evapo-rust. Nice thing about it is, it doesn't harm paint or rubber. I had a really crusty swap meet find commercial hubcap and I soaked it and it looks great now. I've also done disc brake calipers that I didn't want to bead blast the bores or disassemble the rear parking lever assemblies. I'll be doing my fuel tank soon, plugging the bottom (the few rusty spots are just on the bottom fortunately) and putting a gallon or so in for a day.

One thing to keep in mind, depending on the metal content of the parts, if you let them soak for an excessive period they can turn black-ish in spots. Sometimes you only need 12 hours or so of soak time. Days aren't necessary.

Fri Oct 14, 2016 7:20 am

GLHTurbo wrote: How does paint react to the metal after treating it with phosphoric? Do you need to do anything other than rinse with water?

My experience is that it depends...

I left one of my fuel tank cover plates (Single Cab truck) that looked to have original paint on it, albeit thin paint, submerged in Phosphoric overnight to treat some rust and it did start to soften and lift the paint, but that was after 12 hours submerged.

I've painted part of the area under the front seat (thick original paint) and it had no effect whatsoever.

Likewise the modern paint used in the respray on the truck's outer body panels appears to be impervious to it.

Fri Oct 14, 2016 8:28 am

GLHTurbo wrote: How does paint react to the metal after treating it with phosphoric? Do you need to do anything other than rinse with water?

Are you asking how paint applied to the treated metal behaves?

Fri Oct 14, 2016 8:41 am

nlorntson wrote: GLHTurbo wrote: How does paint react to the metal after treating it with phosphoric? Do you need to do anything other than rinse with water?

Are you asking how paint applied to the treated metal behaves?

Yes.

Fri Oct 14, 2016 8:59 am

GLHTurbo wrote: nlorntson wrote: GLHTurbo wrote: How does paint react to the metal after treating it with phosphoric? Do you need to do anything other than rinse with water?

Are you asking how paint applied to the treated metal behaves?

Yes.

Ahh. Well it is used as metal prep so it should be fine. No need to neutralise, just rinse. It stops reacting once the rust has been converted. I guess any other treatment depends on the paint system used.

Fri Oct 14, 2016 12:20 pm

rinsed or not rinsed as long as you let the phos acid dry it is a great primer.