Evapo-rust on the cheap

[seber]

The MDS for Evapo-rust only lists "chelating agent" and less than 1% detergent plus water. Has anyone tried EDTA as a substitute? It would be extremely cheap by comparison and there are only a few chelating agents in existance.

 

[jmarkwolf]

Some are edible, some apparently not so much.

I think I'll stick with my Evaporust.

It's $20 per gallon at Tractor Supply, but can be used over and over.

 

[measuredtwice]

There are previous posts about it on Garage Journal.

What is your source for cheap EDTA?

From Grainger, it's $50 for 500g. --> https://www.grainger.com/product/31FY25

You will also need additional reagents which will be an additional cost --> https://patents.google.com/patent/US20040102344A1/en

For comparison, 1 gallon (slightly less than 4 liters) of Evaporust costs around $25. Recently I bought several gallons of Evaporust for less than half that price (see hot deals on Garage Journal).

Do you have a cheaper source for the reagents?

 

[Davefr]

Just buy a pail of feed grade Molasses and mix it with 85-90% water. It does the same thing but just takes longer.

 

[seber]

There are previous posts about it on Garage Journal.

What is your source for cheap EDTA?

From Grainger, it's $50 for 500g. --> https://www.grainger.com/product/31FY25

You will also need additional reagents which will be an additional cost --> https://patents.google.com/patent/US20040102344A1/en

For comparison, 1 gallon (slightly less than 4 liters) of Evaporust costs around $25. Recently I bought several gallons of Evaporust for less than half that price (see hot deals on Garage Journal).

Do you have a cheaper source for the reagents?

https://www.walmart.com/ip/Tetrasod...ng-Agent-Sequester-Metal-Ions-5-Lbs/950772393
five pounds $25.
Best I've seen for Evaporust is $30/gallon. That is probably one pound of EDTA.

 

[Mohawk Dave]

I've said it before... Citric acid powder from Amazon. 5 lbs for $15 makes 40+ gallons.

Its the main thing/chemical in evapo-rust.... But it will flash rust afterwards.

I'll use citric acid for big large items first, as to not waste evapo-rust... Then I put them in evapo-rust for the final fine tune.

 

[toplessHO]

I've said it before... Citric acid powder from Amazon. 5 lbs for $15 makes 40+ gallons.

Its the main thing/chemical in evapo-rust.... But it will flash rust afterwards.

I'll use citric acid for big large items first, as to not waste evapo-rust... Then I put them in evapo-rust for the final fine tune.

wouldnt spraying with a phosphoric acid like OSPHO after final rinse take care of the flash rust problem?

 

[Shiftless]

I don’t think Citric Acid is the main ingredient in Evaporust.

I use a lot of Evaporust. After soaking, the part is black. I rinse that off with a stiff brush under running water. Then I dry the piece with a heat gun and either primer paint it right away or in most cases, rub on a thin coating of boiled linseed oil or Fluid Film.

 

[Mohawk Dave]

I don’t think Citric Acid is the main ingredient in Evaporust.

I use a lot of Evaporust. After soaking, the part is black. I rinse that off with a stiff brush under running water. Then I dry the piece with a heat gun and either primer paint it right away or in most cases, rub on a thin coating of boiled linseed oil or Fluid Film.

ethylenediaminetetraacetate or EDTA is the chelation agent in ER......which is pretty much tanic acid, which is what citric acid consists of.

ER adds a polymer agent and a detergent.

I don't know what is in ER that allows the workpiece not to flash rust?

The black you see on the part is the carbon being pulled out from the surface. Citric acid and ER both cause this if left in too long. (Which is why you won't really see it on low carbon steels, alloys, etc.)

 

[4xdog]

As one who's worked doing practical chemistry around polymers and coatings for over forty years, that business about "chelating agent" is BS. Sure, it may contain a chelating agent to tie up the black stuff (reduced iron, I believe). But that ain't how it works.

I don't believe citric acid either. The pH is wrong.

My guess is that it's closer to Davefr's comment about reducing sugars (feed grade molasses). I'll bet a nickel Evapo-Rust is based on a weak reducing agent, which gives electrons back to the iron to convert oxide to metal. That's where the black stuff comes from (there's no way it's carbon being extracted from steel), why it gets exhausted when its reducing potential is finished, and why it's safe for plastics, coatings and non-oxide finishes.

A safety data sheet technically needs to show only hazardous ingredients, and even then there are trade secret exemption provisions. The SDS doesn't count as an ingredient disclosure -- not even close.

 

[Farmall450]

As one who's worked doing practical chemistry around polymers and coatings for over forty years, that business about "chelating agent" is BS. Sure, it may contain a chelating agent to tie up the black stuff (reduced iron, I believe). But that ain't how it works.

I don't believe citric acid either. The pH is wrong.

My guess is that it's closer to Davefr's comment about reducing sugars (feed grade molasses). I'll bet a nickel Evapo-Rust is based on a weak reducing agent, which gives electrons back to the iron to convert oxide to metal. That's where the black stuff comes from (there's no way it's carbon being extracted from steel), why it gets exhausted when its reducing potential is finished, and why it's safe for plastics, coatings and non-oxide finishes.

A safety data sheet technically needs to show only hazardous ingredients, and even then there are trade secret exemption provisions. The SDS doesn't count as an ingredient disclosure -- not even close.

Yeah, I'm guessing there's a bit more to the story than you'll learn from the MSDS. Just wait for Evap0-Rust from HF

 

[Skin]

Just get a 5 gallon bucket. Comes out closer to $15/gal than $20 and you get a handy soak basket inside. Stuff will last you years.

 

[4xdog]

Just get a 5 gallon bucket. Stuff will last you years.

I'm working through one of those buckets right now, in fact. It's a convenient way to have a lot to work with.

 

[MileHighRover]

Get a 55 gallon drum. Why cheat yourself?

 

[Mohawk Dave]

4xdog, you surely know more about the chemistry than I. I'm not a chemist and do not pretend to be one. My information just came from internet research.

But I do have a question. Your comment about not believing citric acid.... did you mean the chemical makeup or did you mean that you don't believe that works to remove rust? Because it definitely works very well at removing rust. I have a batch going almost Non-Stop for the last couple years.

 

[M6erfan]

Pep Boys has an online promotion right now that makes 1 ga Evapo-Rust $14.99. I just ordered 3 gallons for in store pickup.

https://www.pepboys.com/evapo-rust-super-safe-rust-remover-1-gallon/product/206426?quantity=1

I actually prefer the 1 ga size as I meter it out into whatever size container I need and not contaminate the whole batch.

 

[DaveInHouston]

I’ve had good luck with Oxalic acid. You can buy the crystalline powder cheap on Amazon. Mix it with water and it works pretty quickly. Obviously depends upon how strong you mix it. I thought it worked better than Evaporust.

 

[JR 42]

I read 4xdog's comment as relating to Evaporust, not a general statement. How many acids don't remove rust?

 

[Rinspeed]

But I do have a question. Your comment about not believing citric acid.... did you mean the chemical makeup or did you mean that you don't believe that works to remove rust? Because it definitely works very well at removing rust. I have a batch going almost Non-Stop for the last couple years.

What concentration are you using and what do you store it in.

 

[Jswain]

What concentration are you using and what do you store it in.

Start out low and increase as needed. For rusty bolts 1/2-1 cup to a gallon of water works pretty good in half a day. Store in a sealed container. Very cheap and fast

 

[tool_scrounge]

Just buy a pail of feed grade Molasses and mix it with 85-90% water. It does the same thing but just takes longer.

This is what I do. Works great. But in did run onto a 5 gallon pail that did not work. I found the feed store had changed brands. I went back to the old brand and everything worked fine again. Very strange. I wonder if it was added preservatives or what?

 

[Shiftless]

This is what I do. Works great. But in did run onto a 5 gallon pail that did not work. I found the feed store had changed brands. I went back to the old brand and everything worked fine again. Very strange. I wonder if it was added preservatives or what?

In case I decide to try something other than my usual Evaporust, what brand of feed store molasses should I look for? I sure don’t want to get stuck with 5 gallons of molasses that won’t remove rust.

 

[Motown]

I use Lysol toilet bowel cleaner, works fast, and the metal comes pretty clean. Its under $3 a bottle.

 

[tool_scrounge]

In case I decide to try something other than my usual Evaporust, what brand of feed store molasses should I look for? I sure don’t want to get stuck with 5 gallons of molasses that won’t remove rust.

https://krusefeed.com/product/molasses-5-gal/

This worked really well for me. I suspect the difference is this is "pure cane molasses". The one that did not work had a label with all sorts of preservatives.

 

[Shiftless]

Thanks for the tip T.S.