PSA: Be very careful using Evaporust. I learned of the downsides... the hard way.

[GregG]

For basically anything rust-related, I use Evaporust.  Usually, for chemicals, the safety to efficacy relationship is inverse; the more effective a chemical is, the less safe it is.  Evaporust seems to have hit a nice sweet spot in that curve, where it is very safe, and very effective....mostly.

I learned the hard way that you should not use Evaporust on watch movements.  Or at the very least, do not use them on any part of the going train if they're composed of steel.  According to their website, Evaporust causes a phenomenon called "carbon migration."  Since steel is Carbon and Iron, and Evaporust removes Iron, you're left with just carbon on the surface, including in between pinion leaves, which seemingly can only be removed via manual scraping.  And you have to put a good amount of elbow grease into scraping it off, and one slip and you'll definitely destroy the part.

One watch was completely locked up, the other is limping by with maybe 60 degrees of amplitude.

Just putting this out there in case anyone else thinks to try it.

[ManSkirtBrew]

Thanks for this. So far I've only been using it on rusty stems with good results. Also the rusty spring on my garden shears that I left out in the rain

[nickelsilver]

No free lunch. Many of the old books mention using xyz acid to remove the blue from tempering (after heat treatment), but how long to leave the part? Acid, in numerous forms has been used for rust removal over the years, Naval Jelly being a big one, which for all of Evaporust's efforts to hide their formula, is essentially what it is. It doesn't reallly hit the steel, it really hits the iron oxide, but, as Einstein would attest, time is a factor.

 

Not too long ago I put some hands in a 12 percent solution of sulphuric acid, bolstered by something I read in Gazeley or DeCarle, and forgot about them until the morning. There was an outline of the hands in the jar, but no more hands.

 

There's another issue using acids to remove rust on springs and things, which is hydrogen embrittlement. I remember reading about a BMX racer, who took a rusty vintage frame and soaked in muriatic acid for a few hours to remove the rust (I did the same on rusty gas tanks from cars when I was a young mechanic), he did a simple jump and the frame disintegrated on him.

 

On something like a massive 20kg 4 jaw chuck evaporust is probably the bees' knees. For little, critical stuff, no.

[VWatchie]

11 hours ago, nickelsilver said:

There's another issue using acids to remove rust on springs and things, which is hydrogen embrittlement.

I know very little about chemistry, but I assume that vinegar also counts as an acid. If so, is there any other way to remove the rust? I always use vinegar to remove rust. It usually works well, but quite often the parts are discoloured depending on the type of metal.

Here is an example of a setting wheel and a date corrector operating lever from an ETA 2892-A2 that has been discoloured by using vinegar.

[GregG]

Great pictures.  I'm seeing exactly the same thing.  Strangely, the black discoloration is not uniform.  I work on Timex watches almost exclusively.  After soaking, their gears are still shiny, but their pinion leaves turn black.  If you look at a non-rusted Timex, the pinions are already a different color from the gears, like they're made of different materials, and the pinions are always the ones to rust.  So I'm thinking maybe the pinions are made of carbon steel, whereas the gears are made of stainless steel or zinc-plated or something.

Regardless, I want to try to find a way to loosen the carbon.

Part of the problem is that the carbon is really on there.  Your fingers will get a little dirty if you touch it, but you have to scrape to get it off.  I had hoped that the ultrasonic would get it off, but I tried that to no avail.

I did see a product called Carbon-Off that's used to dislodge carbon from cookware and machinery. Perhaps a light soak in that would loosen it enough that the ultrasonic could do its work.... or it could destroy it entirely... who knows?

Edited January 9, 2023 by GregG

[nickelsilver]

7 hours ago, VWatchie said:

I know very little about chemistry, but I assume that vinegar also counts as an acid. If so, is there any other way to remove the rust? I always use vinegar to remove rust.

 

I say if it works for you then go for it. I don't really know the details of the hydrogen embrittlement, just enough that it makes me wary.

 

I mechanically remove rust; for complex shapes like pinion leaves I would use a fiberglass brush. For flat parts I use micron graded abrasive paper, typically 12 micron or finer. To get at the sides and in grooves I might use a piece of the paper stuck on a small flat piece of metal, used as one would use a file, or I might use a fine diamond burr- these are 15mm or so long tapered diamond coated bits run in a hand motor (Dremel/Proxonn type tool). It's tedious, but it does work and often you can restore the original look to the part, not counting some pitting that might require too much metal removal to eliminate.

[GregG]

Found the pictures I was looking for.

[Birbdad]

Honestly this might be a product to avoid. I soaked some things in it and now they're covered in a glue like substance that i can't seem to remove. 
Anybody have any idea what on earht is going on? it's coating jewels and metal parts, it's bizarre. I'm not sure but it might have been because i removed parts from the evaporust and then cleaned them in naptha. 

Anyidea on how i can remove it?! I'm thinking maybe acetone might do the trick but i'm unsure how that will react to metal and brass parts with delicate plating. I don't know much about the stuff.

[GregG]

59 minutes ago, Birbdad said:

Honestly this might be a product to avoid. I soaked some things in it and now they're covered in a glue like substance that i can't seem to remove. 
Anybody have any idea what on earht is going on? it's coating jewels and metal parts, it's bizarre. I'm not sure but it might have been because i removed parts from the evaporust and then cleaned them in naptha. 

Anyidea on how i can remove it?! I'm thinking maybe acetone might do the trick but i'm unsure how that will react to metal and brass parts with delicate plating. I don't know much about the stuff.

I had the same issue, but the solution is very simple: the solvent for evaporust is water.  It's completely immune to naphtha 

[rossjackson01]

After discussion I have found 'H & P Story horological rust remover' as a recommendation. I obtained a bottle. It states, soak for 5 minutes then rinse. 

[Birbdad]

8 hours ago, GregG said:

I had the same issue, but the solution is very simple: the solvent for evaporust is water.  It's completely immune to naphtha 

hmm, i did briefly try that on one of the afflicted wheels, i'll try letting them soak in it for a few minutes and report back. 

I' see this stuff so highly recommended i assume there has to be a correct way to use it. Maybe you have to do your entire wash/degreasing routine and THEN use it,then wash again?

[GregG]

2 hours ago, Birbdad said:

hmm, i did briefly try that on one of the afflicted wheels, i'll try letting them soak in it for a few minutes and report back. 

I' see this stuff so highly recommended i assume there has to be a correct way to use it. Maybe you have to do your entire wash/degreasing routine and THEN use it,then wash again?

I also used warm water and made sure to agitate it.

[xyzzy]

Rinse in water immediately after using it, or you get the sticky coating.  IPA is a good way to dry after rinsing, as it absorbs water and evaporates quickly.

[Birbdad]

So i got the rest of the parts soaking in water. A paintbrush and water did get it off of my test wheel after soaking and agitating it in water for an hour so it looks like it works! that's a relief and i can continue with my project watch.

[Birbdad]

Ok so I'm not entirely sure what the best practice with this stuff is other than to maybe avoid it alltogether. But I did FINALLY get the parts clean.
I had to soak the parts in water to get the evaporust goo off them and brush them with a soft brush, this of course caused them to rust requiring me to soak them in the evaporust again, which caused more goo to appear. I put them in water, brushed them again and immediately spun them through 99.9% ipa, then ran them through my 4 stage cleaning procedure with naptha and ipa. 

Lost practically a whole afternoon to it. Getting the jewels clean in particular was a massive pain in the ass. Use this stuff sparingly.

[GregG]

1 hour ago, Birbdad said:

Ok so I'm not entirely sure what the best practice with this stuff is other than to maybe avoid it alltogether. But I did FINALLY get the parts clean.
I had to soak the parts in water to get the evaporust goo off them and brush them with a soft brush, this of course caused them to rust requiring me to soak them in the evaporust again, which caused more goo to appear. I put them in water, brushed them again and immediately spun them through 99.9% ipa, then ran them through my 4 stage cleaning procedure with naptha and ipa. 

Lost practically a whole afternoon to it. Getting the jewels clean in particular was a massive pain in the ass. Use this stuff sparingly.

You can dilute the evaporust with water to make it more gentle.  I still do not endorse using it, even in its weaker form, on any movement.  But if you have having trouble with a layer of goo, you might try diluting it.

[Birbdad]

10 hours ago, GregG said:

You can dilute the evaporust with water to make it more gentle.  I still do not endorse using it, even in its weaker form, on any movement.  But if you have having trouble with a layer of goo, you might try diluting it.

Yeah, i got the stuff so i'll experiment on some of the junk movements i got, some of which have a good bit of rust but i still want to part them out and catalog the spare stuff.
Next time i will definitely try the watchmakers de ruster somebody else mentioned.

[GuyMontag]

I've had really good results with Evaporust. I tend to use it in my ultrasonic with the solution at around 90 degrees F but I only use it for 30 minutes or so max. I also first use a brass wire wheel on my handpiece to clean off the bulk of the rust and then put it in the Evaporust / ultrasonic. If I'm remembering correctly I've only ever used it on screws and keyless works/ motion works parts.

Edited February 21, 2023 by GuyMontag

[Waggy]

I have a small jar or this stuff and use it sparingly - as I remove a rusted or rust stained part I drop it onto the jar and let it sit for 5 mins whilst I continue to disassemble the watch. I then take it out and give it a rub with tissue, if it's clean I put it with the other components, if not then it goes in for another 5 mins and so on. I find this gets rid of light rust, without blackening the part. If these short soaks aren't working then the part is probably too far gone and a new part is required anyway. I especially like this method to remove light rust and rust staining over using abrasive materials as it reduces additional damage to the part to almost zero compared to abrasive compounds/sticks etc.

I have noticed that the rust remover leaves the part sticky, almost like it had been in a sugar solution, but a quick 5 min clean in soapy water in the ultrasonic seems to remove this prior to the normal cleaning regime.

To summarise, I have had good results in removing light rust/staining using these 5 min soak and inspection cycles, but would advise against leaving parts to soak for long periods as they tend to blacken and if the multiple short soaks aren't enough the part is probably too rusted to use anyway.

[rjenkinsgb]

I've been using a rust removing formula posted by one of the science channels (Elementalmaker) on youtube.

That consists of 5g tetrasodium EDTA per 100ml deionised water, plus a small amount of citric acid to bring it back to around 6.5ph, using ph test paper.

It works in a similar way to evaporust, but using a different chelating agent and seems rather milder.

I have only used it on tools and non-critical parts so far, but the results have been excellent.

These are some parts I've done today; the spring winding arbours were probably in for around 4 - 5 hours as they had heavy rust, and the taper pins & screws for a couple of hours is it was fairly light surface rust. You can see darker grey mottling on the arbours from where rust had stated to eat in to the surface.