Home made "Evaporust" formula

[Jelly_Sheffield]

I would have to assume here that most posters to date have not actually used Evaporust!

It works much faster and better than Citric acid and does not require heat or anything.

I have a bucket full of the stuff, and it's good enough on small fiddly stuff to warrant the price IMO, but still messy and slow like every other chemical de-rusting process.

I used evaporust on some Mercedes parts and was very impressed. Anything no matter how heavy the rust was came out totally rust free about 24 hours later. No agitating or heat required very simple. And those parts did not flash rust either even sitting for a couple of weeks in the garage. So I'd go as far to say there is a corrosion I hibititing finis on the part when fished out of the evaporust.

As per the patent information above, Evaporust is effectively a citrate buffer, with a catalytic amount of phosphate, pH adjusted for best reactivity with Sulphuric Acid...

Like a citric acid bath that's been given every possible chemical advantage to live its best rust-eating life.

There's no corrosion inhibitors in there, and I know from experience that Evaporust cleaned parts can and do flash rust.

The pH adjusted nature of Evaporust will definitely reduce the likelihood of flash rust relative to any free acid.

It's also possible that the phosphate causes some conversion coating effect in the same way that Phosphoric Acid does, so if the container your Evaporust is in has a small skim of oil contamination, you're inadvertently giving them an ultrathin coat of black phosphate and oil every time you lift them out.

 

[rtcosic]

Hexamine.
That's the chemical I was trying to recall. Someone suggested it functions as a buffer and corrosion inhibitor. I bought some solid fuel tablets of hexamine from a link provided on that post.
The Mamodsteam engine thread prompted my recollection.

 

[fizzy]

Hexamine.
That's the chemical I was trying to recall. Someone suggested it functions as a buffer and corrosion inhibitor. I bought some solid fuel tablets of hexamine from a link provided on that post.
The Mamodsteam engine thread prompted my recollection.

Wonderful stuff Hexamine - used for making r d x - wonder why they banned it

 

[rtcosic]

Hexamine.
Hmm, these solid fuel tablets aren't very soluble.

Why am I surprized? It's solid fuel for use by the military in front line conditions, so being soluble would hardly be an advantage.

The individual tablets are wrapped like dishwasher tablets. The cardboard container hasn't fared so well over the years.

Chocolate teapots?

 

[Jelly_Sheffield]

Hexamine.
Hmm, these solid fuel tablets aren't very soluble.

Why am I surprized? It's solid fuel for use by the military in front line conditions, so being soluble would hardly be an advantage.

The individual tablets are wrapped like dishwasher tablets. The cardboard container hasn't fared so well over the years.

Chocolate teapots?

View attachment 459196View attachment 459197View attachment 459198

Isn't it meant to be used like camphor, pop some in a closed container and it slowly sublimates, then the vapour condenses on surfaces leaving a protective film?

It definitely has an appreciable vapour pressure at room temperature, because that's what makes it easy to light as stove fuel (and why it's supplied sealed in little plastic packs)

 

[rtcosic]

Isn't it meant to be used like camphor, pop some in a closed container and it slowly sublimates, then the vapour condenses on surfaces leaving a protective film?

It definitely has an appreciable vapour pressure at room temperature, because that's what makes it easy to light as stove fuel (and why it's supplied sealed in little plastic packs)

No idea!

That's another interesting avenue to explore.
Shall experiment and may even remember to report back.

 

[JMS1972]

FWIW I tried the the receipt above with Washing soda and Citric acid today.

Before (TIG and silver soldered part)

After - soaked for about 4 hours with occasional rub with soft wire brush or stainless pan scourer

All the black oxides have gone and after a rinse with distilled water. Ready for paint.

Pretty pleased with the results. Water was from the tap and container sat in bright sunshine so vaguely warm today.

 

[JMS1972]

And here's a drill chuck that had light surface rust

After

Worst side

Seems a lot more effective than just citric acid and leaves a better finish.

 

[rtcosic]

No idea!

That's another interesting avenue to explore.
Shall experiment and may even remember to report back.

The hexamide has dissolved.
It has the unusual propertry of being less soluble in hot than cold water, so starting out with hot water didn't help.
The tablets have a wax coating to prevent them dissolving. I had cut one in half so a small surface was exposed.

The overall recipe was:
1 litre water
100gm citric acid
40 gm sodium carbonate
12 gm hexamide
15mls Lidl W5 Floor Cleaner

 

[JMS1972]

The hexamide has dissolved.
It has the unusual propertry of being less soluble in hot than cold water, so starting out with hot water didn't help.
The tablets have a wax coating to prevent them dissolving. I had cut one in half so a small surface was exposed.

The overall recipe was:
1 litre water
100gm citric acid
40 gm sodium carbonate
12 gm hexamide
15mls Lidl W5 Floor Cleaner

That reminds me I forgot about adding soap whoops!

It still worked though.

 

[bigegg]

Made a batch this afternoon, hoping to use it as a spray-on/brush on "converter".
It does *something* - sort of a sticky coating?
I'm going to wash it off tomorrow to see the result.

 

[bigegg]

Update:
It had no real effect where sprayed. Probably dried too fast as it was in direct sun.
However, where it pooled, it formed a sticky coating almost like half-dried PVA glue.
It was difficult to rinse off, but jet washed off easily, leaving clean metal.
But ONLY where it pooled, so probably no good for spray application

 

[JMS1972]

Update:
It had no real effect where sprayed. Probably dried too fast as it was in direct sun.
However, where it pooled, it formed a sticky coating almost like half-dried PVA glue.
It was difficult to rinse off, but jet washed off easily, leaving clean metal.
But ONLY where it pooled, so probably no good for spray applicationView attachment 459496

Maybe wrap it in cling film to prevent it from drying out?

 

[bigegg]

Maybe wrap it in cling film to prevent it from drying out?

I was hoping to use it to spray my car chassis - but difficult to cling-film that.

I'm gonna order 5 gallons of milk stone remover and spray that on.

 

[JMS1972]

I was hoping to use it to spray my car chassis - but difficult to cling-film that.

I'm gonna order 5 gallons of milk stone remover and spray that on.

You're gonna need a bigger roll

 

[rtcosic]

I wonder if Alginate or some other gelling agent could be used to make a jelly like form that could be applied to chassis components and wrapped in cling film?

Chitosan?
Gelatin?
Pectin?
Agar?

Anyone brave enough to raid SWMBO's jam making cupboard?

 

[Ross365]

I just stumbled upon this company, offering an interesting range of chemicals in small quantities https://shop.hdchemicals.co.uk/collections/chemicals.
Might be worth a look when making up home-brew rust removers etc.

 

[Agroshield]

I do not know if anyone here has seen it but there is a video by a channel called 'Mass Spec Everything' entitled "What's the Secret Rust Remover in EVAPO-RUST by Mass Spec Everything on LCMS". For those who understand the chemistry, it might offer some further insights.

​

 

[Screwdriver]

I do not know if anyone here has seen it but there is a video by a channel called 'Mass Spec Everything' entitled "What's the Secret Rust Remover in EVAPO-RUST by Mass Spec Everything on LCMS". For those who understand the chemistry, it might offer some further insights.

​

Sounds like that must be the solution (lit.)

OTOH it also acts as a chelating agent in the rust removal process so the concoction in the original video is derusting with a similar process.

I am still not convinced it's much "better" than citric except for the potential to keep a large bucket on hand without it growing a forest of nasties over time. I have not tested that yet. I do still have the original test but I kept it indoors and even pure citric would not develop mould unless kept outside where bugs and stuff inevitably find their way into it.

Interesting variation on pricing. Zoro has it for £70/l whereas Etsy has "the same" 99% at £15/l for cosmetic production.

Not sure exactly what they mean by "99% pure" so the price difference might just be a weaker dilution. I mean, who is going to test the concentration and the temptation to water it down if you're selling it by the litre (on Etsy) must be overwhelming. Obviously a chemist would know, as would a supplier like Zoro but in the consumer marketplace where tightwads like me hang out, it's probably going to be a false economy...

 

[tigdlo]

Anyone know the difference between anhydrous and monohydrate citric acid? Which would be needed to the concoction in the video in the first post?