PDA

View Full Version : Evaporust is discounted until July 29th



woodPixel
25th July 2018, 01:31 PM
Evapo-Rust - Supercheap Auto (http://www.supercheapauto.com.au/articles/parts-servicing/evapo-rust/254)

If you've ever thought to give it a go. It is 100% amazing witchcraft!

onetrack
26th July 2018, 11:19 AM
I use Citric Acid, it's vastly cheaper than those price-rorting "Secret Formula" products, such as Evaporust. Citric Acid costs around $3.00 to $4.00 a kg.

A kilogram of Citric Acid will provide around 2000 litres of cheap rust-removing solution - which is 100% safe, non-toxic, gives off no fumes, and it doesn't damage base metal.

The Citric Acid solution can be used repeatedly for weeks, provided the solution is covered to prevent evaporation, and degradation by strong sunlight (UV rays).

https://www.westchem.com.au/products/citric-acid-powder

BobL
26th July 2018, 01:42 PM
Even though it's vastly overpriced there's no comparison between Evaporust and any acidic rust remover because Evaporust is a chelating agent rust remover. This means it is totally safe and unlike acidic converters whereby if you forget about them then they will always dissolve some (or a lot of) metal even when it may not look like it it has.

A cheap chelating agent rust remover is molasses but it's slow (days instead of minute) and it stinks.

Provided you remember to wire things correctly, electrolysis is another safe (turn on and forget) method of rust removal. If the voltage is kept low (ie 6v so don't use a car battery or cR battery charger) then fumes are kept to minimum. If something like foot bath salts are used as the electrolyte salt and a Carbon rod is used as the anode no anode sludge is generated and the electrolyte can also be re-used.

onetrack
26th July 2018, 02:53 PM
...unlike acidic converters whereby if you forget about them then they will always dissolve some (or a lot of) metal even when it may not look like it it has.I've never had a problem with Citric acid dissolving any of the the good base metal. If you use a strong acid such as Hydrochloric, Sulphuric or Nitric acid, you're just looking for metal-dissolving trouble.

The only "accident" I've ever encountered with using Citric acid, is - I once used a baked enamel cast iron bath for an acid tub. The baked enamel promptly disappeared, like icing off a cake, at a kids party!
I'll put my Citric acid bath up against your Evapororust bath any day! - and I'll bet you won't see any difference in results - but you'll feel the difference in your wallet!

These high-priced "magic" rust dissolvers are on a par with all the fuel additives. You pay out $10 worth of fuel additive per tank to get maybe $10.50 in fuel savings - which are always difficult to quantify precisely, because no-one carries out strict, independent, additive testing!

Even the phosphoric rust remover gels are dreadfully overpriced, for what they achieve.

woodPixel
26th July 2018, 03:11 PM
Dude, I'm not so sure why you are going mental over this.

It's a product. It works. It is proven. It's used extensively in industry - especially with car restoration.

It does exactly what it promises on the bottle and it is absolutely not some "fuel additive" like scam.

I've used my last tub to absolute death. The container cleaned a lot of my early cheap second hand tools to absolute perfection. I have photos of an ancient vice that was a blob of rust, half in and half out of the liquid.... After a night, the side in the solution was like brand new.

Personally, I think it works. It's chemistry, but it's as close to magic as I've ever experienced.

BobL
26th July 2018, 03:30 PM
I think you misunderstood me - I am not a fan of Evaporust either and agree that products like evaporust are waaaaay over priced - I have never bought any and am unlikely to ever buy it. However, unlike fuel additives there is a lot of serious science behind the use of Chelating agent based rust removal. Chelating agents are sometimes even added to acidic based rust removers. The Uni where I used to work had a Corrosion Research Institute and this was sometimes discussed which is how I came to know about it.

woodPixel
26th July 2018, 03:37 PM
I've been doing a bit of reading.

There are many people who swear by citric acid as an effective remove. I've not found any side by side comparisons yet, but I guess they'd be out there.

As for evaporust. It is apparently a combination of EDTA at 5% and a pH modifier to get it to 7.5

Reading up on EDTA is illuminating. It is used to "remove metal oxide scale from heat transfer surfaces in boilers and nuclear reactors".

Some serious people doing serious chemistry in that industry!!!

BobL
26th July 2018, 04:31 PM
As for evaporust. It is apparently a combination of EDTA at 5% and a pH modifier to get it to 7.5

It also contains 1% detergent to act as a wetting agent.
The MSDS of Evaporust I have seen place the EDTA at 15%, so in 1L there's about 150g.
On ebay pure-ish bulk EDTA costs between 3 and 10c a gram, so 1L has about $5-$15 worth of EDTA

EDTA does not dissolve easily in pure water so sodium hydroxide or ammonia are needed to raise the pH to get it to dissolve.
You could just buy the EDTA, dissolve it in water with about 10% by weight of NaOH and then add acid to get the pH back down to around 7 (you would need some pH paper or better still a pH meter to get it right), and finally add a squirt of dishwashing liquid.

There are many EDTA rust removal patents out there including several that use citric acid/Ammonia.

onetrack
26th July 2018, 04:57 PM
FYI - Citric acid is a naturally-occurring chelating agent. It does exactly what Evaporust does - and possesses the same attributes as Evaporust brags about, on their bottle - at much lower cost.

I know all about chelating agents, I have a pretty reasonable grasp of chemistry, having owned an AAS and done considerable amounts of gold extraction from tailings - utilising, and dealing with, a wide range of chemicals, minerals, and their associated compounds and reactions. I have to confess, I actually built a private lab under Mum and Dads house when I was 14! I also kept a good record of all the chemical experiments I carried out there! If they only knew!

Chelation is extensively used for dealing with heavy metals and toxin buildups in the body. My wife went to an old Scottish doctor who specialised in blood chelation for general health improvement. She swore the benefits were tangible.

Jeffen
26th July 2018, 09:24 PM
I can't agree with some of these statements.

The only rust removal agent I use (and have used many times on many different metals) is citric acid - white knight concrete etch.
It works really well, but on a couple of occasions I have left the item in the bath much longer than intended, only to have it ruined.
One item was just a scraper that had some surface rust, (but not on the edges as it normally had plastic sleeves covering them.

I completely forgot about it and after about 4 days I recovered it, with up to 4mm deep gouges in the edge.
Completely my fault, and there wasn't much need to derust it anyway, but as far as citric acid not eating base metal,
just wrong. It might not do much damage to a plane body (I've de-rusted plenty of those) but for smaller items and particularly alloys, you have to be careful.

If monitored appropriately, then yes, it is a very cheap, safe and effective rust removal method, and I'm happy to continue using it.

Jeff

onetrack
26th July 2018, 10:48 PM
Nowhere in the MSDS for White Knight Concrete Etch, does it say the product is pure citric acid. All the MSDS says is >60% citric acid.
It doesn't say there are no other additives, that may be synergistic to citric acid, or improve or facilitate its interaction with concrete to improve its etching ability.

The MSDS merely says - "There are no additional ingredients present which, within the current knowledge of the supplier and in the concentrations applicable, are classified as hazardous to health or the environment or have an OEL and hence require reporting in this section."
In other words, there may be other ingredients added which do not need to be listed, as they are regarded as benign. That other 40% of the ingredients in the Concrete Etch may contain a chemical that damaged your scraper.

Secondly, I don't know why anyone would want to pay $23 for 1 kg of what is obviously, largely citric acid, when you can buy pure, food grade citric acid for $3.00 - $4.00 a kg, or even less if you buy in bulk.

Beardy
27th July 2018, 07:54 AM
All good info here
Where do you buy pure citric acid?

onetrack
27th July 2018, 11:36 AM
Where do you buy pure citric acid?As a Sandgroper, if I quickly need a small quantity, I get it from the bulk food suppliers such as Kakulas Bros in central Perth, or Kakulas Sister in Fremantle and Nollamara. I think Citric acid is $4.50 a kg from them.
But to buy in bulk, I go to Able Westchem (I already provided a link to their website in post #2). Able Westchem are just around the corner from my workshop, a great bonus.

For those in the other regions, look up wholesale food suppliers or chemical suppliers. Some will deal with the public, some won't. These suppliers will usually only supply a minimum of a 20kg bag.
You can get it off eBay at higher prices.
For those in the Sydney region, NuuVee Essentials in Gosford supply Citric acid in containers ranging from 1Kg at $11.90, to a 20kg plastic bucket at $98.00.

You can possibly get some off your local friendly baker, if you're up early enough - they use it in bread as a preservative, and it's often sold as a "bread improver".

You can get it from people selling bath-salt and soap-making supplies - Citric acid is added to "bath bombs", it provides the fizz when they hit the bath water.
Lastly, Gooogle is your friend, just type in "Citric acid supplies", plus your state or region, and I'm sure you'll get plenty of hits.