EvapoRust Side Effects

iron_junkie · May 20, 2012

Hi all,

Have been using Evaporust during the restoration I'm working on and noticed that it seems to effect "cast iron", if you leave the part soaking in for at least 2 days. The rust comes off as advertised, but it seems that it takes pristine iron down with it. Surfaces that were rust free and machined smooth, end up looking very ruff, dull, and have an etched surface appearance. Anyone else notice this, and if so, what the maximum time limit you would leave a cast iron part soaking in this product?

On the other hand, steel (iron+carbon) parts seem to be unaffected. Only the rust comes off, and there is no change in surface finish on areas that were clean and rust free. Hardened steel seems to acquire a patina of sorts if you leave in it after a while, although I've only seen this once so far.

Cheers

S_W_Bausch · May 20, 2012

"How To Use EVAPO-RUST

Step by Step Instructions

In a container, pour a sufficient amount of EVAPO-RUSTâ„¢ to completely cover the rusted object.
Immerse the rusty object in the solution and leave it for 10 minutes for light rust or up to overnight for extremely heavy rust.
When finished, rinse item with water. If deep rust remains in pits, re-immerse item until all the rust is gone. Un-rusted metal will not be affected. NOTE: This stage is VERY important in getting the best results.
To prevent flash rusting, dip the item back into solution. Then allow item to air dry. This will prevent rust for up to two weeks.

Heavy rust removed in six hours at room temperature."

iron_junkie · May 20, 2012

"If deep rust remains in pits, re-immerse item until all the rust is gone. "

Yes, and with the part I was working on, I still had rust after a day. Which is why it sat there for 2 days until I noticed other areas being affected. So they do not give a maximum time limit, unless you consider "overnight" to be the maximum you should have the part in.

"Un-rusted metal will not be affected."

There are many types of metals. In this case, cast iron seems to be affected if left in for at least a day or two. Which is why I'm asking if anyone else noticed this.

And yes, I've read the instructions, so no need to be cheeky.

Cheers.

Ohio Mike · May 20, 2012

I've soaked items for days at a time. I like Purple Power, a scrub brush with 100F wash after removing the items. The hot wash helps with evaporation of the water to avoid flash rust. That light discoloration you see is easily knocked off with a soft wire wheel.

kozzmo99 · May 21, 2012

you may have had some corrosion that you didn't see?

the only thing I have noticed with evaporust is sometimes you get that blackened metal effect or a black line if any part sits outside the dip.

david

kgize · May 21, 2012

iron_junkie said:
Surfaces that were rust free and machined smooth, end up looking very ruff, dull, and have an etched surface appearance. Anyone else notice this, and if so, what the maximum time limit you would leave a cast iron part soaking in this product?

Yes - I have noticed that. Furthermore, on at least one piece I de-rusted with EvapoRust (vintage mill table lock handle) that i only partially submerged because only part of item had rust - 'good metal' was taken off -enough to feel difference with finger (enough to measure - but I haven't) - enough that I could not take out the 'line' between evaporusted area and not-evaporusted area with steel wool or polishing. That part was left in about a full day. The claim that good metal is not affected in any way is not exactly true if you leave it in too long - and how much good steel is affected seems to depends on the steel type too. Still it is good stuff - but don't leave valuable parts in too long I have learned

MichaelP · May 21, 2012

The only time I've seen a disastrous effect of Evaporast was when I put a blackened part into it. In a short time all the blackening was gone.

I don't know what method was used to blacken the part (in fact, it was a very dark brown color), but it was an old fixture made by a very skillful toolmaker.

Mud · May 21, 2012

Black Oxide is Iron Oxide, just like rust, and that's what Evaporust dissolves, so it's instantly gone.

The interface between Evaporust and air seems to remove the metal, I don't know what that effect is called, but I've never had metal removed from submerged steel. I've soaked a piece of cast iron for a long time without visual damage, but it wasn't real pretty to begin with so maybe I wouldn't have noticed. I have noticed that old darkened Evaporust will leave a dark stain on just about any steel if left in long enough, and the higher carbon content of the steel the sooner it will appear, even with fairly fresh Evaporust. I've also noticed a dark deposit on top of thick rust barnacles that stops the process. These photo are of a water pump that was really thick with barnacles inside. I had to pull it out every other day and brush off the black deposit from the barnacles to get the Evaporust to resume working. This is a pretty extreme case though, and I was deliberately testing what it would do. If I put something sensitive in it, I use fairly fresh liquid and check it every 2 hours. I've done some nice measuring tools and fixtures without any ill effects.

jCandlish · May 21, 2012

I asked my local lubricant supplier about a Chelatkomplexe (<-- look it up) and the chemist overheard. It turns out Motorex (my local supplier) has one. Curisouly, the recommended use is as an additive to water soluable coolants or grinding lubes as a water softener????

What's that about???

Anyhoo, the MSDS is here (google B.S. restrictions apply) -> https://docs.google.com/file/d/0B-r0kOumKPg2V2xnaWNPaWJ3MFk/edit

MichaelP · May 21, 2012

Mud said:
Black Oxide is Iron Oxide, just like rust, and that's what Evaporust dissolves, so it's instantly gone.
.

I'm not sure Evaporust affects all iron oxides. For example, black oxide screws don't lose their oxide layer.

iron_junkie · May 21, 2012

Thanks for replies everyone.

I'm figuring that less than 12 hours of submersion should be a safe bet for cast iron parts. Again, steel seems to not be a problem, as I've soaked steel parts for 3 or 4 days with no apparent effect to unrusted surfaces. But yeah, Evaporust is the best/fasted rust removal method I've come across so far, and I'll continue using it.

If time allows it, I might do a comparison of it's effects on different metals by soaking various, clean, unrusted pieces in a fresh batch of Evaporust, and monitoring what it does over few days period. Taking pictures every 12 hours or so. But I need to finish the lathe first. Hehe.

Cheers

Knolltop Farms · Jan 13, 2017

I know this is an old thread, and many may have found all the answers they're looking for when it comes to the product, but the "Cast Iron Issue" is still of interest to me, especially with a couple of restoration jobs coming up. This is what I found and have concluded on the subject.

The quality or type of Cast Iron, and/or Tool Black, seems like it may be the factor in the "etching" encountered on some parts after longer soaks. I say "may" with a lean toward probably after reading the "How does Evapo-Rust work?" on their FAQ page, and seeing this statement:"The active ingredient in EVAPO-RUST® bonds to iron exclusively. It can remove iron from iron oxide but is too weak to remove iron from steel where the iron is held much more strongly.", and thought to myself 'OK,so it bonds to Iron exclusively, but can't break the bond with Carbon in steels, so what happens when there is only Iron in your part?'

Sounds like Cast Iron parts need to be watched closely when soaking for extended periods, and may not be our best choice when cleaning precision fit surfaces. I wondered why it seemed to work much better on hand tools than lathe parts, and now I know...or at least I think I know. And next to knowing, thinking you know is the best thing...right? LOL! Below is the entire answer to the question from the EVAPO-RUST® website. Thanks for listening, and any additional info or anecdotes would be greatly appreciated. Aloha...Chuck

"EVAPO-RUST® works through selective chelation. This is a process in which a large synthetic molecule forms a bond with metals and holds them in solution. Most chelating agents bind many different metals. The active ingredient in EVAPO-RUST® bonds to iron exclusively. It can remove iron from iron oxide but is too weak to remove iron from steel where the iron is held much more strongly. Once the chelating agent has removed the iron, a sulfur bearing organic molecule pulls the iron away from the chelator and forms a ferric sulfate complex which remains water soluble. This frees the chelating agent to remove more iron from rust."

crij · Jan 18, 2017

Evapo-Rust probably either removed unseen rust around the Silicon-oxide (slag) pockets and between iron crystals or it has dissolved the silicon-oxide it self. I know Evapo-Rust attacks other metal oxides, if you drop in galvanized (zinc-oxide) or cad plated (cadmium-oxide) parts, the coatings are removed instantly and all you see is a gel (booger like object) coming off the part(s). Found this out when I used a collection of bolts and pins to lift a part off the bottom of a tank. As soon as I filled the tank the gel formed and once the part was done I washed off the bolts (formerly cad plated or galvanized) and they instantly flash rusted.

Rich C.

Rex TX · Jun 3, 2017

Old thread, but....

Evaporust does indeed etch a line when your part sticks out of the fluid. I have a parallel that has a very deep diagonal line (~.005") on it. Lesson learned.

I have soaked many cast iron parts for as long as 2 weeks without any negative effects. One was a Wade bed. It came out clean as a whistle, no etching or metal loss. I have also soaked a Logan bed that was heavily rusted. Ways are sharp as new, though the pits have become "oil reservoirs".
Some of that black stuff still seeps out even years later. It turns the way oil black. I don't know that that hurts anything.

I noticed my warehouse had re-order Evaporust after being out of it for over a year. I was surprised to see that a 5-gallon pail was now $56 - about 30% less - but they were out of stock. They substituted a 3.5-gallon pail for $41, and it comes with a nice plastic dip basket.

So apparently the wholesale price dropped considerably. I'm not seeing any price reductions elsewhere though,

promacjoe · Jun 3, 2017

For those who are interested, Here is a interesting series of videos. It shows different methods of rust removal. From electrolysis, to using molasses. it's broken down into several parts So you can watch the ones that you are interested in. It also shows a good comparison of each method side-by-side. Comparing results and time necessary for use.

MrPete222 "Tubalcain", rust removal playlist.

Stay safe and have fun.
Joe.

Rex TX · Jun 10, 2017

One more side effect, albeit a good one: Evaporust dissolves that baked on, nasty brown stain that accumulates over decades of honest use. They all have it, particularly on the sides of the bed. I usually start with WD40 to clean it, then I try wheel cleaner, which gets all but the worst. Last is soaking in Evaporust. Besides removing any rust present, it also will remove almost all of the stains, leaving (usually) the OE paint nice and clean. It also softens that dried coolant that seems to be impervious to everything I have tried.
I save the depleted Evaporust for just this purpose. Once it stops working on rust, it still removes the spooge and stains for a while longer.

SGM Dan · Apr 16, 2021

Evapo Rust leaves a yellow residue on the metal in my gas tank. I don't have access to wire brush it off. How can I neutralize this inside the tank and behind the baffles in order to prepare it for tank sealer such as POR 15? I've contacted the company several times through several methods to no avail, their customer service is nonexistent. Need help please.

Rex TX · Apr 16, 2021

It washes off easily with water and detergent. If the tank is small enough (Motorcycle?) I would add a quart or so of water with detergent, then a big handful of BBs or something similar. Then cap it and agitate it.

Scottl · Apr 16, 2021

MichaelP said:
The only time I've seen a disastrous effect of Evaporast was when I put a blackened part into it. In a short time all the blackening was gone.

I don't know what method was used to blacken the part (in fact, it was a very dark brown color), but it was an old fixture made by a very skillful toolmaker.

Likely the part was browned using the same techniques as for finishing parts for old muzzle loaders and replicas.

If the part is boiled after the rust browning method it becomes rust blued, otherwise it is simply oiled or oiled and waxed to prevent further rusting.

john.k · May 3, 2021

Seen a few reports on other forums of damage done by evaporust......its well known there is corrosive effect at the air fluid interface......but in one instance a flat spring under tension disintegrated,claimed hydrogen embrittlement,and in another ,the jaw screws in an old chuck were made to partially disintegrate.....Now I gather these problems have occurred after prolonged soaking......never a wise thing to do in any chemical fluid you arent familiar with.

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