What, exactly, is patina?

[Edward Miller]

I have a mix of tools--some new, some old. I feel like every time I turn around, my shiny new Lie-Nielsen #7 has a spot of rust on it somewhere, despite my best efforts. Contrast this with my roughly 100-year-old Stanley #5 that never rusts. And that's pretty typical in my shop. New tools need to be vigilantly protected from rust, while old tools are fine as is. Why? What, exactly, is this magical patina that prevents rust, and how could I promote its development on my newer tools?

Anybody know?

[george wilson]

Guns are blued or RUST BLUED to protect them against rusting. Of course,these finishes do not prevent rust,but they slow it down a bit from starting.

Your old Stanleys,which I imagine are dark looking as opposed to shiny and bright,have a natural occurrence of this "rust bluing",and probably over the years have also absorbed a certain amount of oil,from their irons being sharpened on oil stones(Which used to be the ONLY commonly used type stone in the USA),as well as oil from hands. Cast iron is porous and can absorb some oil. We used to "season" cast iron frying pans by heating them up when full of oil. As they cooled off,some oil was further sucked in.

So,this is likely why your old tools don't rust as readily. Try keeping your new plane oiled. Wipe it off before use. It will get oil into the cast iron,too. But perhaps not as readily as old cast iron. The new planes are made of malleable iron,which is cast iron with the excess carbon baked out of it at high temperatures for hours. It might not be as porous as regular cast iron. I'd have to research it.

[bridger berdel]

In short, patina is the visible effect of age. As iron ages the corners wear a little, the faces get scrapes and dings, the polish of manufacturing fades and the surface shows signs of chemical interactions with it's environment. Much of that is iron oxide, the same rust you find so unsightly when it's a spot in the middle of a polished surface. Some is the effects of iron interacting with other chemical compounds. Small amounts of sulphur will turn iron jet black if the conditions are right. George is right on about the effects of oil on iron.

I really like the look of aged patinated iron rubbed smooth by time and put to work with a coat of paste wax. I have a very nice #3, type 10 or so that some well meaning soul did a complete restoration of. All the iron surfaces were polished, the lever cap was nickle plated and the japanning was stripped and either re-japanned or painted. I prefer the more naturally aged planes. I have a woodriver #1 plane, all shiny and new. Every time I pull it out I think about ways to make it look old....

[Patrick Chase]

Unlike Bronze Iron doesn't develop patina in the sense of a chemically passive oxide that occurs without any sort of coating or conversion process.

George outlines one strong possibility: Iron has multiple oxides, of which rust (Fe2O3) is the most problematic one. Magnetite (Fe3O4) is more stable, so if you can convert the surface layer to Magnetite then you can delay (not indefinitely) the onset of rusting. Bluing is a family of electrochemical conversion processes to do just that. The problem here is that Magnetite doesn't "just happen" on its own the way a Bronze patina does, and it should be pretty obviously dark if it's there. It should be the color of a black oxide drill bit ("black oxide" is nothing more than Magnetite).

One other possibility is the difference in Iron composition and grain structure. The old Stanleys are conventional cast gray iron, while the L-N is ductile iron. Totally shooting from the hip here, but the latter may be more rust prone. Now that I think about it I'm pretty sure I've encountered more rust on my ductile iron Veritas planes than on older ones, though it's been a nonissue since I got serious about prevention (short summary: CRC 3-36, liberal use of VCI squares and sometimes capsules, VCI paper for long-term storage, thorough drying/oiling after water exposure).

[george wilson]

I mentioned that there could be a difference in porosity between the malleable iron LV and LN planes,and plain old cast iron. So we agree on that,but you might Google about it and check it out,Edward. In any case,keep a light coat of oil on your new planes,and do wax them,too.

[Kees Heiden]

Okay, I don't really know the answer but I do have a theory ;)

You see a similar corosion resistance in wrought iron. Wrought iron has various layers, some are more ferrous, other more carbonous. Those carbonous layers rust a lot less quickly. They kind of form a barrier for the oxygen to go deeper. At least that is how I understand the process.

Gray iron has about the same amount of carbon as nodulair or ductile iron. In gray iron the carbon forms layers around the ferrous crystals. In nodulair iron the carbon clusters in small balls and sits in between the various ferous crystals, like you can see very well in this picture:

http://www.iron-foundry.com/blog.files/cast%20iron%20microstructure.jpg

This comes from this website: http://www.iron-foundry.com/grey-iron-vs-nodular-iron.html

As you can see, the carbon in gray cast iron tries to surround the ferrous crystals, so I could imagine that this makes the metal more corrosion resistant.

Of course, leave the old Stanley plane in a humid garden shed for a couple of years and it will have rusted nicely too.

[Patrick Chase]

I mentioned that there could be a difference in porosity between the malleable iron LV and LN planes,and plain old cast iron. So we agree on that,but you might Google about it and check it out,Edward. In any case,keep a light coat of oil on your new planes,and do wax them,too.

You're right, you did. I didn't acknowledge that because of less-than-thorough reading on my part. Sorry about that.

[mike holden]

Patina

: a thin usually green layer that forms naturally on the metals copper and bronze when they are exposed to the air for a long time
: a shiny or dark surface that forms naturally on something (such as wood or leather) that is used for a long time
: a thin layer

-Merriam Webster Dictionary

In other words, corrosion, dirt, wear, and age

Did You Know? Italians began using "patina" in the 17th century to refer to the green film that is produced on the surface of copper. They borrowed the word from Latin, where it means "a shallow dish." (Presumably, the Italian meaning developed from the observation of such film forming on copper dishes.) By the mid-18th century, English speakers were also calling the green film "patina." And by the early 20th century, "patina" was being used in English for the gloss of polished metals, like silver, as well as wooden furniture - a meaning that led to its literary use for a surrounding aura, as demonstrated in this quote from Stella Gibbons' Cold Comfort Farm (1932): "The very atmosphere seemed covered with a rich patina of love."




It's like being "cool" if you got it, you got it. You cant go out and get it.
Mike

[Bill White]

Having fought the rust issue for many years, I came upon the Paul Sellers posting about the stupid simple "oil pot". Just a small can with a coiled rag impregnated with oil.
I use it after each use, and it keeps the planes/chisels lubed lightly. Does not seem to change any patina.
Plain old 3 in 1 oil.
What's not to like?
Bill

[Patrick Chase]

Okay, I don't really know the answer but I do have a theory ;)

You see a similar corosion resistance in wrought iron. Wrought iron has various layers, some are more ferrous, other more carbonous. Those carbonous layers rust a lot less quickly. They kind of form a barrier for the oxygen to go deeper. At least that is how I understand the process.

Gray iron has about the same amount of carbon as nodulair or ductile iron. In gray iron the carbon forms layers around the ferrous crystals. In nodulair iron the carbon clusters in small balls and sits in between the various ferous crystals, like you can see very well in this picture:

This comes from this website: http://www.iron-foundry.com/grey-iron-vs-nodular-iron.html

As you can see, the carbon in gray cast iron tries to surround the ferrous crystals, so I could imagine that this makes the metal more corrosion resistant.

Of course, leave the old Stanley plane in a humid garden shed for a couple of years and it will have rusted nicely too.

That argument makes sense, though I don't know enough to know if it's actually right :-).

I would note that even if it is more rust-prone I think that ductile cast iron is a better material for metal planes. You can avoid rust on ductile iron easily enough, but there's no way to make grey iron stronger or less brittle.

[Kees Heiden]

I don't know if I am right either...

Maybe better wait for a real metallurgist to add her/his knowledge.

BTW, another disadvantage of ductile iron is, it scratches easier. Old gray cat iron is quite a bit harder. So, as long as you don't drop the plane on a stone floor, the oldies seem to be a little "better".

[Mike Brady]

I mentioned that there could be a difference in porosity between the malleable iron LV and LN planes,and plain old cast iron. So we agree on that,but you might Google about it and check it out,Edward. In any case,keep a light coat of oil on your new planes,and do wax them,too.

I'm no metallurgist, but I concur that my L-N iron body planes are slightly more rust prone than my old Stanleys. I'm not saying its a problem, but I am pretty religious about keeping the castings wiped off after use and sharpenings. I use that spray made by Boeing. Boeshield.

[Rich Riddle]

Patina is a nice word for rust as replica is a nice word for copy or fake.

[Patrick Chase]

I'm no metallurgist, but I concur that my L-N iron body planes are slightly more rust prone than my old Stanleys. I'm not saying its a problem, but I am pretty religious about keeping the castings wiped off after use and sharpenings. I use that spray made by Boeing. Boeshield.

I used to use that. I think there are better options.

If you store your tools in an enclosed space then corrosion inhibitors are an option, whether of the new sort (VCI) or Camphor.

CRC 3-36 works better than Boeshield for me. Boeshield relies on depositing a dry wax film on the metal surface, and that can be rubbed or scuffed off fairly easily. 3-36 and a couple of the others create nondrying films that are somewhat self-healing. They all use volatile aliphatic (non-aromatic, not-Benzene-like) hydrocarbons as vehicle/solvent. The respective MSDSs say they're all pretty safe (much more so than, say, Kerosene, which can have significant aromatic content), but some folks may be sensitive anyway so take that for what it's worth.

[Patrick Chase]

Patina is a nice word for rust as replica is a nice word for copy or fake.

Its meaning (http://www.merriam-webster.com/dictionary/patina) is much more specific than that. Patina is the stable thin film of visible oxidation that forms on Bronze etc. Rust (Fe2O3) is certainly visible oxidation, but it isn't a film, doesn't stay thin for long, and certainly isn't stable.

[Stewie Simpson]

Patrick; any thoughts on using Evapo-Rust as a rust protection agent on cast and ductile steel. Within the attachment it states its effective for up to 4 weeks after application. I have 5 Litres in the workshop. From previous experience of using this product, it will generally darken the appearance of the base metal prior to being cleaned off. Need to bear that in mind prior to use as a rust inhibitor.

Stewie;

http://www.evapo-rust.com/product-info/technical-info/#tds

[Patrick Chase]

Patrick; any thoughts on using Evapo-Rust as a rust protection agent on cast and ductile steel. Within the attachment it states its effective for up to 4 weeks after application. I have 5 Litres in the workshop. From previous experience of using this product, it will generally darken the appearance of the base metal prior to being cleaned off. Need to bear that in mind prior to use as a rust inhibitor.

Stewie;

http://www.evapo-rust.com/product-info/technical-info/#tds

I've never used EvapoRust, so no direct experience. It appears to work very differently than Boeshield/3-36/WD40/etc, which are petroleum-based and work by displacing water and creating a film or solid layer to excludes Oxygen and water vapor. In other words, they work by creating barriers.

(http://www.evapo-rust.com/product-info/technical-info/#msds)Its MSDS (http://www.evapo-rust.com/product-info/technical-info/#tds) instead implies that Evaporust works by chelating (https://en.wikipedia.org/wiki/Chelation) the Iron and thereby breaking the Iron-Oxygen bonds of rust molecules and preventing more such bonds from forming. Presumably the chelate has a life of "up to 4 weeks" in air. If I had to guess I'd bet that the "up to" part depends on humidity, as the chelate has to be water-soluble (if it weren't then it would only convert the surface layer of rust, since Evaporust as a whole is water-based). The detergent is probably there to enable it to penetrate gaps that are so small that surface tension would prevent water alone from passing.

You could argue (very broadly) that Evaporust is more akin to bluing than to petroleum-based barrier products, in that both Evaporust and bluing chemically modify the surface of the iron to render it incapable of forming rust.

[Frank Martin]

I also notice my LN planes are a lot more rust prone than my Veritas planes. I don't have many vintage planes, so can't speak to them.

[Stewie Simpson]

Patrick; trialled the Evapo-Rust a Stanley #5 body and plane iron parts. Surface was cleaned down with Meth. Spirits prior to application. Wipe on with a dampened rag (non diluted), allow 20 -30 sec to penetrate, then wipe the surface dry with a clean rag. Repeated 3 times to insure good coverage. Very slight blueing effect to the base metal, but hardly worth noting. The blueing effect seems to be more dramatic over a longer term soaking, akin to the instructions listed for de-rusting. Wiping the surface dry after 20-30 sec. seems to prevents isolated areas of darker colour caused by a pooling effect. Now its down to mother nature to see if any traces of rust oxide will appear inside 4 weeks.

regards Stewie;

http://i1009.photobucket.com/albums/af219/swagman001/evapo%20rust/_DSC0242_zpskmnbwpb1.jpg (http://s1009.photobucket.com/user/swagman001/media/evapo%20rust/_DSC0242_zpskmnbwpb1.jpg.html)

http://i1009.photobucket.com/albums/af219/swagman001/evapo%20rust/_DSC0243_zpslwczgemj.jpg (http://s1009.photobucket.com/user/swagman001/media/evapo%20rust/_DSC0243_zpslwczgemj.jpg.html)

[Dave Anderson NH]

Stewie, Please resurrect this thread or start a new one in about 4 weeks so that you can report your results. I'm sure quite a few people will be very interested.

[Patrick Chase]

Patrick; trialled the Evapo-Rust a Stanley #5 body and plane iron parts. Surface was cleaned down with Meth. Spirits prior to application. Wipe on with a dampened rag (non diluted), allow 20 -30 sec to penetrate, then wipe the surface dry with a clean rag. Repeated 3 times to insure good coverage. Very slight blueing effect to the base metal, but hardly worth noting. The blueing effect seems to be more dramatic over a longer term soaking, akin to the instructions listed for de-rusting. Wiping the surface dry after 20-30 sec. seems to prevents isolated areas of darker colour caused by a pooling effect. Now its down to mother nature to see if any traces of rust oxide will appear inside 4 weeks.

Wiping the surface may be problematic. Their instructions for rust prevention are to "dip the item back in EVAPO-RUST solution and allow to dry", which suggests that the protective layer may not take nicely to wiping while wet (as previously noted the chelate has to be water soluble, so wiping while wet may remove it).

I also suspect that the "darker color" may in fact be the chelate.

[Stewie Simpson]

Patrick; after reading your post, what benefit would there be in reporting back my findings. If it works, it makes you look like an idiot. If it doesn't work, I will have to put up with you telling me I told you so.

regards Stewie;

[Patrick Chase]

Patrick; after reading your post, what benefit would there be in reporting back my findings. If it works, it makes you look like an idiot. If it doesn't work, I will have to put up with you telling me I told you so.

regards Stewie;

I don't see why it would anybody look like an idiot or justify an "I told you so". Experimenting with stuff like this inevitably involves guesswork based on incomplete data and blind alleys. That's why I used words like "may be", "suggests", and "suspect" in #21.

[Stewie Simpson]

Patrick; being a water based product I am hoping the process I followed does work. If it doesn't, I am looking a lot of surface rust to clean up in 4 weeks time.

cheers Stewie;

[Patrick Chase]

Patrick; being a water based product I am hoping the process I followed does work. If it doesn't, I am likely looking a lot of surface rust to clean up in 4 weeks time.

cheers Stewie;

I think the situation could (note "uncertain wording" once again) be in between those extremes. If you leave the Evaporust anywhere then the chelating agent that it contains should protect the surface at least until the water evaporates off, so I don't think that the water from the Evaporust will itself cause rusting.

It seems to me that the risk is that wiping the Evaporust off would remove the chelate and thereby prevent it from inhibiting rust caused by *other* moisture sources that don't include the chelating agent. If that's the case then you won't be any worse off than if you'd never applied the Evaporust to begin with (except inasmuch as doing so caused you to not do something else to prevent rust).

With all of that said, I'd probably test it on some other piece of iron first :-).

[Andrey Kharitonkin]

Having fought the rust issue for many years, I came upon the Paul Sellers posting about the stupid simple "oil pot". Just a small can with a coiled rag impregnated with oil.
I use it after each use, and it keeps the planes/chisels lubed lightly. Does not seem to change any patina.
Plain old 3 in 1 oil.
What's not to like?
Bill
Did anyone try to use Fluid Film for oiling iron planes and such? Compelling thing is that it can be had at different viscosity and it is claimed to be non-toxic (wool fat). Smells a little bit like bull shit or sheep but anyway :)

[Chet R Parks]

Andrey
I am far from being an expert on lubrication but I'll give a big thumbs up for Fluid Film. I use it on everything from my tractor linkage to car door gaskets to keep them from freezing and everything in-between. I especially use it in my oil pot to wipe down all my tools during and after use. I think it's great stuff.
Chet

[Pat Barry]

I'd worry that leaving the Evaporust on the clean metal surface will actuallly become counterproductive and promote rust formation rather than eliminate it. Does any technical info exist related to long term exposure of the evaporated residue from Evaporust?

[Stewie Simpson]

Pat; can you expand your theory further.

regards Stewie;

[Patrick Chase]

I'd worry that leaving the Evaporust on the clean metal surface will actuallly become counterproductive and promote rust formation rather than eliminate it. Does any technical info exist related to long term exposure of the evaporated residue from Evaporust?

Ordinarily I'd agree, but the manufacturer's technical data sheet (Stewie linked it earlier in the thread) specifically says to "let the tool dry" when coating for rust protection.

Given that it's a chelating agent I can see how that could work.

[Mike Henderson]

I'm late to this thread but I've used Evaporust on rusted steel and unless I put some coating on it (I use wax) it will rust again in time. Here in CA it's pretty dry and even in this environment, unprotected metal rusts after you take it out of Evaporust.

Mike

[Andrey Kharitonkin]

Andrey
I am far from being an expert on lubrication but I'll give a big thumbs up for Fluid Film. I use it on everything from my tractor linkage to car door gaskets to keep them from freezing and everything in-between. I especially use it in my oil pot to wipe down all my tools during and after use. I think it's great stuff.
Chet
Thanks Chet. Should have used search first. Appears like quite some people are using it. Then I should be fine to use it while hand planing.

I'm using Camellia Oil at the moment, but someone here said (while discussing oil pots) that it is most likely just mineral oil, especially if it comes in plastic bottle. That scares me off a bit, kind of. Plus Fluid Film is like WD-40 claimed to displaces water and adhere to metal better.

[Patrick Chase]

Thanks Chet. Should have used search first. Appears like quite some people are using it. Then I should be fine to use it while hand planing.

I'm using Camellia Oil at the moment, but someone here said (while discussing oil pots) that it is most likely just mineral oil, especially if it comes in plastic bottle. That scares me off a bit, kind of. Plus Fluid Film is like WD-40 claimed to displaces water and adhere to metal better.

What scares you about mineral oil?

Fluid film is simply yet another blend of aliphatic petroleum oils (http://ihiqa2kjxfb4dhp9872la1cm.wpengine.netdna-cdn.com/wp-content/uploads/2016/07/SDS_NAS.pdf), just like 3-36 and WD40. Fluid film contains paraffin so it appears to rely on depositing a dry coating like WD40, but all 3 (plus plenty of others) are just variations on a common theme. Mineral oil is also composed of aliphatic petroleum distillates, so I doubt there's any difference in terms of safety. If one of them is a problem for you then they're all a problem.

[Andrey Kharitonkin]

What scares you about mineral oil?

Fluid film is simply yet another blend of aliphatic petroleum oils (http://ihiqa2kjxfb4dhp9872la1cm.wpengine.netdna-cdn.com/wp-content/uploads/2016/07/SDS_NAS.pdf), just like 3-36 and WD40. Fluid film contains paraffin so it appears to rely on depositing a dry coating like WD40, but all 3 (plus plenty of others) are just variations on a common theme. Mineral oil is also composed of aliphatic petroleum distillates, so I doubt there's any difference in terms of safety. If one of them is a problem for you then they're all a problem.

Heh, alright, they are all the same. The scary part is the purity of aliphatic oils and presence of other compounds, like aromatic cycles that are known to be unhealthy. Something like baby oil would be nice, if it could be used for planning. Since I have kids running around my shop space and touching everything.

[Mike Holbrook]

Interesting thread. I have used Evapo-Rust (ER) a great deal, for several years now. The directions on the new bottle I have say to submerge the object in the solution for 1-12 hours depending on amount of rust, which is the way I have always done it. If I do not have enough solution I just add water. I added water to the original gallon of Evapo-Rust I bought several times over 6 months to a year and it still seemed to work fine, if a little slower. The directions suggest covering larger objects in paper towels soaked in the solution, trying to eliminate air bubbles. I find that not submerging the entire object leaves a line, after a few hours.

The bottle I have says to wash the object with water after removing it from the soaking process. I have had issues with my skin and have reason to be super careful so I always wash and scrub the ER off after using it. ER leaves a blackish residue where the rust use to be that in my experience is easy to brush off under water. This can result in "flash" rusting fairly quickly though, particularly if any moisture is left on the surface.

I often handle this issue by using Camella oil to do a final wipe/cleaning. I also have used Renaissance Wax (RW), a micro-crystalline wax/cleaner/polish after washing the objects off. Renaissance Wax is "expensive", available from Highland Woodworking. I have a 230 ml can of RW I bought something like 20 years ago. I have used it often. The surface of the contents has a depression but that is about all. It still seems about the same texture too. It says to use "very small amounts". In this particular instance "very small" may be an over statement. Though it may be expensive I can not imagine ever using an entire can of it, and I often wax entire machine/table/metal surfaces with it. I understand RW is used in many museums to preserve old wood and metal objects. Might be worth considering.

I seem to have negative skin reactions to WD-40, and probably some other oils but no issue with Camellia oil that I have seen so far.

[lowell holmes]

I don't know about patina, but Johnson's wax applied occasionally certainly helps. Conservators wax helps as well.:)

[Patrick Chase]

Heh, alright, they are all the same. The scary part is the purity of aliphatic oils and presence of other compounds, like aromatic cycles that are known to be unhealthy. Something like baby oil would be nice, if it could be used for planning. Since I have kids running around my shop space and touching everything.

Yeah, you're certainly at the mercy of the manufacturer to get the distillation and subsequent processing right and keep the aromatics down (for everybody else, think "benzene").

[Stewie Simpson]

2 weeks into trialling the Evapo-Rust, the obvious signs of surface rust are visible. No point taking this trial any further, I will clean up the surface rust, and get back to using an oil and wax as a protective rust barrier.

Stewie;


(2 weeks ago)
http://i1009.photobucket.com/albums/af219/swagman001/evapo%20rust/_DSC0242_zpskmnbwpb1.jpg (http://s1009.photobucket.com/user/swagman001/media/evapo%20rust/_DSC0242_zpskmnbwpb1.jpg.html)

(now)
http://i1009.photobucket.com/albums/af219/swagman001/evapo%20rust/_DSC0271_zpsntbhzhy5.jpg (http://s1009.photobucket.com/user/swagman001/media/evapo%20rust/_DSC0271_zpsntbhzhy5.jpg.html)