My guide to the best vinegaroon you've ever made.

[kop4]

 

My all in one guide to Vinegaroon

Hey everyone. I’ve been lurking around these forums for a while now and haven’t posted much, so I thought I’d finally make a contribution. I’m going to University for a Chemistry degree, and surprisingly some of the things I’ve been learning in my labs are actually applicable to my leatherwork! I thought I'd write up some of my observations and experiments with vinegarroon, to try and help shed some light on what is actually going on in the reaction. Please, read through and share any knowledge you have working with this stuff!

 

(I know this is a lot. I was bored just typing it. You can skip to the bottom if you don't have time to read it all)

 

Background

Vinegaroon, or ‘roon, is a homemade black ‘dye’ that has been used by leatherworkers for centuries. It is also used by woodworkers to ‘ebonize’ wood, and was used since the 5^th century as ink, called ‘iron gall ink’. It is not actually a dye, but a reaction between ferric acetate and the tannins that naturally occur in leather and wood. Tannins content varies between hardwoods and softwoods, and can be boosted by brewing a strong black tea and wiping it on the wood. I assume that this is also true of leathers. I have a few junky tandy's sides that are pale in appearance, and they seem to be low on tannins because roon has less of an effect on them.

‘Roon is used by many leather and wood workers but understood by few. It can be very useful alternative to commercial black dye in areas where dye is unavailable, too costly, or undesired because of environmental reasons. Also, because it is fundamentally different than other dyes, it will not bleed or crock (rub off) onto fabric.

 

Pros:

• -easy to make with household materials
• -available in places where dye is not, or shipping is too expensive
• -nearly free
• -does not bleed or crock like other black dyes

Cons:

• -often does not make a deep enough black colour without lots of neatsfoot oil added afterwards
• -can make your product smell like vinegar
• -acidic nature can cause issues with metal hardware in contact with the leather, might also degrade then leather after long periods of time

 

Typical Recipe: (not recommended by me)

Put some old rusty nails into a jar of vinegar and let it sit for a week, or a month. Filter it through cheesecloth and wipe it on your leather.

This produces a nasty, smelly mixture of a whole bunch of iron complexes and compounds. The active ingredient, iron acetate, is in there, but along with a whole bunch of other junk you don’t need. It doesn’t have to be this way. With some chemistry and a little bit of research into the mechanism here, I’ve made a crystal clear, mostly odourless solution that only takes half a day to make.

 

How I did it:

I bought fine steel wool from the dollar store, which came in small bats. Any steel or iron will do, but fine steel wool has the greatest surface area so it will react the fastest. Metal shavings/powder would also work, but I’d think they would just clump on the bottom of the jar and prevent the vinegar from reaching the bottom layers.

 I washed one bat in soapy water to remove any oils left over from manufacturing. Some people have used acetone, which would work well, but seems a bit over the top when soap is cheaper. I pulled it apart and placed it in a beaker of regular vinegar, so that all the wool was submerged. You don’t need very much steel wool at all, even a quarter of the amount I used would be enough. The amount of metal actually being dissolved is in the order of milligrams or even micrograms. You probably shouldn’t keep a lid on it, because you are producing gas in the reaction.

After a few hours, small bubbles form on the steel wool, causing it to rise to the top of the solution. I would mix it gently to dislodge the bubbles and keep it submerged.  Every few hours I would use an eye dropper (so that I didn’t have to pour it out) to take a bit of the solution and test it on some leather. The darkening effect increased slowly over time until full strength was reached after about 12 hours. Still, I left the wool in there for 2 days to see if it got any stronger. Next time I won’t leave it in so long.

After 2 days, I removed the wool. Since none of the wool was ever exposed to the air above, there was no rust in the beaker and I was left with a nice clear solution that didn’t smell much worse than straight vinegar. This is my vinegaroon solution. It turns leather black, is fairly stable, and is still acidic.

The final product: a clear, nearly odourless solution of vinegaroon.

 

Neutralization (optional):

Next, I tried to neutralize the solution with baking soda to see if that changed the effectiveness of it at all. I took a small test tube of the ‘roon solution and put a spoon tip of baking soda in it. Obviously this will make it fizz up like your kid’s science fair volcanoe project, so I added it slowly.  I didn’t have any pH paper to test the acidity so what I did was add an excess of baking soda (seen on the bottom of the tube), and then re-added the acidic ‘roon solution dropwise until there was no excess left.

These images show the neutralization process, if pH paper is unavailable. A base (sodium bicarbonate/baking soda) is added in excess, which is seen in the bottom of the test tube by the red arrow. Then, the acidic vinegaroon solution is re-added slowly until this excess base disappears. The resulting solution is assumed to be neutral.

 

This neutralized roon solution has the exact same reaction with the leather as the acidic solution. However, it was not as stable. After a hours sitting or a few minutes shaking, the solution turned into a cloudy grey-orange sludge. This is because the oxygen in the air oxidized the Fe2+ ions into Fe3+ ions, which are not soluble and have a rusty colour.

Neutralized roon is good for immediate use, but turns nasty after a while

 

What is happening? (skip this section if you don’t like chemistry)

The iron is dissolved by the acetic acid and becomes a free-floating iron ion, in the +2 oxidation state, called Fe2+ or Iron(II). Hydrogen gas is produced in the dissolution process but in such small amounts that there is nothing to worry about. This ion is colourless and soluble in water, which is what we want. Furthermore, when this ion is in an acidic solution, like vinegar, it is relatively stable. Some of the ions complex with the acetate, which further increases its stability.  When this mixture is applied to the leather, the iron ions interact with the tannins to form an iron-tannin complex, which is black.

Oxygen messes with this system. Obviously there is oxygen in the atmosphere and dissolved in your solution, and this can oxidize the iron ions – it will take them from the 2+ state to the 3+ state. Fe3+ or iron(III) is NOT what we want, because it is orange and gross and not soluble in water. If this forms, it creates an orange/brown powdery solid that sinks to the bottom of the jar. To prevent the oxidation of the iron in solution, we need to keep the pH LOW and keep the oxygen out of the system as much as possible – by not pouring or shaking the solution.

Now, the acidity of the solution is what keeps it stable – I’m assuming that you could store vinegaroon for a few weeks or months if you kept a lid on it. But the acidity is also what makes it dangerous for using with metal hardware. So what I’ve done is neutralized the solution with baking soda, just before applying it to the leather. The neutralized solution is just as effective, but noticeably less stable. The nice clear solution will turn orange overnight if untouched, or in seconds if shaken.

 

 

 

 

So there you have it. Here’s a summary of what you SHOULD do:

• -keep the oxygen out of the system. Oxygen is your worst enemy, and turns this pure, clear solution of iron acetate into a sludgy, brown, stanky mess.
• -keep the solution acidic until you need to use it, then neutralize it if you need to before applying
• -use steel wool, as it has way more surface area than the same mass of solid iron

And what you SHOULDN’T do:

• -don’t use rusty metal. It wouldn’t make a huge difference, it would just be introducing iron(III) into the solution which you don’t want.
• -don’t stir vigorously or pour the solution if possible
• -don’t use lots of metal, cause you only needs a little
• -don’t wait for a week, cause full strength is reached in less than a day
• -don’t put a lid on it until you’ve removed the iron, cause you’re building up gas in that jar
• -don’t worry about anything exploding either, there’s not that much gas
• -don’t filter it! Pouring it would introduce too much oxygen into the system. If you have stuff that you need to remove, it would be better to suck the ‘roon out with a turkey baster or something.

What you could do differently than me:

• -using stronger vinegar, ie pickling vinegar, would speed up the reaction slightly and probably produce better results, since the pH would stay lower. Normal vinegar, however, is fine for most uses.
• -If you want to ensure that you have neutralized the solution, or gain a greater insight into the reaction process, pH paper would be very useful.
• -The solution could be neutralized with other bases, I only used baking soda because it was within an arms reach of the vinegar. Using sodium hydroxide, for example, wouldn’t cause it to bubble so much.
• -The solution can also be heated to speed the reaction, although I personally wouldn’t bother
• -Perhaps the best thing you could do is to calculate just how much iron will react with the vinegar and use slightly less than that amount of steel, to ensure that you have vinegar in excess. This will keep the pH from rising as vinegar is consumed by the reaction. This could be calculated stoichiometrically, or possibly by weighing accurately the mass of steel wool before and after to find out how much was consumed. I would assume that it wouldn’t be very much at all.

 

 

Resources:

The main reason why I found it so hard to find information on this reaction is because I initially had no idea what to search for. “vinegaroon” only can up with a few result, and most of them were not scientific explanations. I soon found out that it is more commonly used for “ebonizing wood” and that yielded a few more results. Finally I came across some scientific papers for Iron-acetate and iron-tannin complexes. Here are links to most of the pages I found helpful in my search:

http://chemistry.stackexchange.com/questions/35351/iron-chemistry-acetates-for-ebonizing-wood

http://chemistry.stackexchange.com/questions/5027/how-does-the-mordant-ferric-acetate-interact-with-tannins-when-ebonizing-wood

https://en.wikipedia.org/wiki/Iron_gall_ink

https://pubs.usgs.gov/wsp/1459d/report.pdf                 

 

 

 

 

Thanks a lot for reading that, if you made it all the way through! Ask me any questions or share your experiences with roon below!

 

 

 

Edited December 5, 2023 by Northmount
OP's request

[Russ]

In the several times I've tried to make and use 'roon, I've never successfully got something completed that didn't stink.  The black was ok after the second or third try, but it still smelled. Talk about ruining a piece.  I finally decided it was simply worth the elbow grease to rub off the black dye pigmentation and use dye.

I would assume that if vinagaroon could be made consistently and bypass the black dye problems, some company would have already made it and tried to market it.

[MADMAX22]

Lots of people have used the steel wool and it has been recommended by many for years even on this forum. It has the most surface area to react so you get the quickest solution. 

Also many suggest giving it a bath in baking soda and water mix to neutralize the acids plus it helps with the blackening effect. 

Thats the way I learned how to do it and it works really well and doesnt have a bad smell once dry and oiled. 

Another thing that can help with this is give it a soak in something with high tannings like boiled walnut husk mix or any other number of things. Chuch Burrows use to recommend this if I remember correctly. 

Oh wanted to add that a few of the items I made using this method were still doing well several years later, well except the one made with tandy crap leather but it was still black just the leather was not holding up as well as the others. Once neutralized with the baking soda bath it didnt adversely affect the hardware either.  

 

Edited January 7, 2017 by MADMAX22

[blazeafar]

Hi kop4, I ran a small experiment on some roon I neutralized with some soda. After it went all rusty and iron encrusted after a day or so I transferred for one container to another and filtered the crud out. The remaining liquid is still a brownish color but I applied this to a piece of scrape leather and it turned black. Not sure at this point how long the neutralized roon will keep, still working on that.

 

Edited December 5, 2023 by Northmount
OP's request

[Mercurye]

Hi Kop4, great instructions. I just have one question: here someone mentions that after about a decade the vinegaroon dissolved the top layer of a belt. Could this be because he possibly did not neutralize the acid? Basically I'm just wondering if vinegaroon dyeing is stable (based on you chemistry knowledge).

 

Thanks,

Austin

Edited December 5, 2023 by Northmount
OP's request

[PlatypusMax]

This is interesting, thank you for sharing your notes! I am experimenting with vinagaroon after learning about it last week. One more thing to throw into the mix is hand warmer packets as a source of iron. I don't have steel wool in the house but since it's ski season in new england, I do have hand warmers. I happened to recall my son once asking me how they work, looking it up and learning that they are made of fine iron shavings and they warm your hand by oxidizing at just the right pace. I tried a recipe that involved both vinegar and peroxide, and it is working ok but is definitely a smelly mess and leaves the leather smelling like vinegar. I'm going to do some more testing with just vinegar then a separate neutralization step. I am also going to try tea-soaking advice I read elsewhere -- anyone have experience with this and have suggestions on what brands of basic cheap tea might have the highest tannin content, and how long to soak? Does the order matter or could you soak in tea after the vinegaroon? Thanks. 

[chuck123wapati]

The smell dissipates after a bit so not a big problem especially after all the other smells from finishing get added, I've used it for years on both wood and leather with no problems. I clean my steel wool with a shot of brake cleaner and a good blow with my air compressor. Its kinda like BLO and beeswax that was used for many things back in the day everything from gun stock finish to oil cloth, I routinely use vinegar to remove rust from old parts and oxidation from old copper switches in my  older vehicles. Here is a sheath I did well over a year ago it wasn't neutralized just let dry and finished, After tooling I dipped the pieces completely in vinegaroon and then let dry. The black goes through 100%, it hasnt tarnished either the snaps nor the brass knife and doesn't smell any diferent than any other leather product.

Edited January 23, 2020 by chuck123wapati
added picture

[Goblinworx]

Curerntly running experiments using iron powder vs steel wool to see if I get a cleaning dying process.

Also the reaction does, create hydrogen gas so completely sealing the vessel from oxygen may lead to some explosive situations (more thinking that the container might rip open, not fireball)

Wondering if a fermentation air lock might work well in this process

[chuck123wapati]

1 hour ago, Goblinworx said:

Curerntly running experiments using iron powder vs steel wool to see if I get a cleaning dying process.

Also the reaction does, create hydrogen gas so completely sealing the vessel from oxygen may lead to some explosive situations (more thinking that the container might rip open, not fireball)

Wondering if a fermentation air lock might work well in this process

i just leave the lid a bit loose, but i only make a pint at at time so not much hydro gas. 

[Samalan]

Chuck nice work on that sheath got to love that Roon .

[Goblinworx]

On 2/14/2021 at 1:26 PM, chuck123wapati said:

i just leave the lid a bit loose, but i only make a pint at at time so not much hydro gas. 

I normally make about a gallon at a time with the plastic jugs the white vinegar comes in. Since I have made it a few times, I took and punched holes in the old vinegar bottle tops and switch them out.

The steel powder is working well from the tests I have done so far.  It's much cleaner and has kept a black color instead of the muddy rust that steel wool makes. It a bit more expensive at $ for 100 grams but I'm happier with his clean it is and also it turns over in just a few days.

[chuck123wapati]

On 2/18/2021 at 4:51 AM, Samalan said:

Chuck nice work on that sheath got to love that Roon .

thank you.

10 hours ago, Goblinworx said:

I normally make about a gallon at a time with the plastic jugs the white vinegar comes in. Since I have made it a few times, I took and punched holes in the old vinegar bottle tops and switch them out.

The steel powder is working well from the tests I have done so far.  It's much cleaner and has kept a black color instead of the muddy rust that steel wool makes. It a bit more expensive at $ for 100 grams but I'm happier with his clean it is and also it turns over in just a few days.

awesome i may have to try that out next batch.

[Goblinworx]

Sorry $10 for steel powder  vs $2 or for steel wool 

[fredk]

On 2/14/2021 at 5:17 PM, Goblinworx said:

Wondering if a fermentation air lock might work well in this process

I do not think so. In fermentation of alcohol you want to exclude oxygen and allow the carbon dioxide to escape through the water trap. The CO2 is pushed out due to pressure build up in the jars. O2 cannot get into the jars through the water trap.

I think a top with holes, with or without short pipes attached, in a well ventilated area is the way to go

[Matt S]

If the OP is still around, I'd be curious about his take as a chemist on using other iron sources for striking leather black rather than everyone tediously reacting their own ferric acetate. With the presence of water almost any source of iron will work. Will Ghormley uses a drum of water with rusty strap iron in it. I'm sure that most of us have noticed that blood does the same job too, as do iron filings (e.g. from a splitting machine). Iron diet supplement pills work if ground up and dissolved in water. I tend to use iron sulphate crystals from the garden centre. All you're doing is providing a way for the iron to react with the tannic acid in the leather leftover from the tanning process to form FEO3 (an insoluble blue-black lake). I have scepticisms on the importance or specialness of vinegaroon in achieving this effect, though I admit that the acid left after the reaction may make a difference in the longevity of the leather -- but that in turn presupposes that the leather isn't washed in plain water after striking (which I presume we're all doing after using any striker including vinegaroon, right? ).

[chuck123wapati]

On 2/27/2021 at 3:43 AM, fredk said:

I do not think so. In fermentation of alcohol you want to exclude oxygen and allow the carbon dioxide to escape through the water trap. The CO2 is pushed out due to pressure build up in the jars. O2 cannot get into the jars through the water trap.

I think a top with holes, with or without short pipes attached, in a well ventilated area is the way to go

Yup an air lock because you don't want wild yeasts from the air to spoil your wine. it would do no real good for roon.

[chuck123wapati]

1 hour ago, Matt S said:

If the OP is still around, I'd be curious about his take as a chemist on using other iron sources for striking leather black rather than everyone tediously reacting their own ferric acetate. With the presence of water almost any source of iron will work. Will Ghormley uses a drum of water with rusty strap iron in it. I'm sure that most of us have noticed that blood does the same job too, as do iron filings (e.g. from a splitting machine). Iron diet supplement pills work if ground up and dissolved in water. I tend to use iron sulphate crystals from the garden centre. All you're doing is providing a way for the iron to react with the tannic acid in the leather leftover from the tanning process to form FEO3 (an insoluble blue-black lake). I have scepticisms on the importance or specialness of vinegaroon in achieving this effect, though I admit that the acid left after the reaction may make a difference in the longevity of the leather -- but that in turn presupposes that the leather isn't washed in plain water after striking (which I presume we're all doing after using any striker including vinegaroon, right? ).

I always thought vinegar was used because it eats up the iron quickly. I use it first on any rusted metals before buying store bought chemicals. Might have to try just water but i think it would take forever and a day to dissolve enough iron. Do you use your iron sulphate in water?

[Matt S]

9 hours ago, chuck123wapati said:

I always thought vinegar was used because it eats up the iron quickly. I use it first on any rusted metals before buying store bought chemicals. Might have to try just water but i think it would take forever and a day to dissolve enough iron.

Rust isn't really water soluble, the water is basically just a way of getting the iron containing molecules into contact with the tannic acid in in the leather fibres in order to react. Mr Ghormley just gives his rustbarrel a good old stir when he needs it to black some leather. I've not used this method but he mentions letting the leather soak in the stuff so I don't think it's as fast a reaction as vinegaroon.

You can see his high tech equipment here: http://www.willghormley-maker.com/MakingHOGRig.html

I know that the rig he's making in that page isn't' very dark, but I think that's a deliberate choice with this piece and of course the darkness varies with the amount of soaking time and amount of tannic acid available in the leather.

Do you use your iron sulphate in water?

Yup, just a teaspoon of crystals in a jar of warm water. Do make sure you wash the leather thoroughly after striking, as the acid it leaves behind is (very weak) sulphuric, whereas the acid from striking with vinegaroon (iron acetate) is acetic acid (vinegar). Veg tan leather "should" be slightly acidic though, so don't go fannying about with baking soda or nothing, you'll do more damage than good. I did some samples years ago, measuring the pH at various stages, and found that just washing in tap water was PD close to what the leather started at.

I'll see if I can dig out my notes but that was a few moves ago so I'm not confident I'll be able to find them. I feel some experiments coming on...

[chuck123wapati]

On 3/1/2021 at 5:36 PM, Matt S said:

 

Yup, just a teaspoon of crystals in a jar of warm water. 

cool indeed i may have to try some i use it for some of my wood projects also. 

[Arturomex]

On 9/3/2019 at 1:07 PM, Mercurye said:

 I just have one question: here someone mentions that after about a decade the vinegaroon dissolved the top layer of a belt.

That link doesn't, anymore. I'm pretty sure there are a lot of people here on the forum who have pieces they've treated that are ten years old. Anybody have anything that old they could comment on? And how they finished it?

On 3/1/2021 at 4:36 PM, Matt S said:

Rust isn't really water soluble, the water is basically just a way of getting the iron containing molecules into contact with the tannic acid in in the leather fibres in order to react. Mr Ghormley just gives his rustbarrel a good old stir when he needs it to black some leather. I've not used this method but he mentions letting the leather soak in the stuff so I don't think it's as fast a reaction as vinegaroon.

You can see his high tech equipment here: http://www.willghormley-maker.com/MakingHOGRig.html

I know that the rig he's making in that page isn't' very dark, but I think that's a deliberate choice with this piece and of course the darkness varies with the amount of soaking time and amount of tannic acid available in the leather.
 

Yup, just a teaspoon of crystals in a jar of warm water. Do make sure you wash the leather thoroughly after striking, as the acid it leaves behind is (very weak) sulphuric, whereas the acid from striking with vinegaroon (iron acetate) is acetic acid (vinegar). Veg tan leather "should" be slightly acidic though, so don't go fannying about with baking soda or nothing, you'll do more damage than good. I did some samples years ago, measuring the pH at various stages, and found that just washing in tap water was PD close to what the leather started at.

I'll see if I can dig out my notes but that was a few moves ago so I'm not confident I'll be able to find them. I feel some experiments coming on...

I'm also going to give that a try. Look forward to your future input on this, Matt.

Chuck, I'm curious about what kinds of wood you're using this on? It'd be a ripper on oak.

Regards,

Arturo

[chuck123wapati]

14 hours ago, Arturomex said:

That link doesn't, anymore. I'm pretty sure there are a lot of people here on the forum who have pieces they've treated that are ten years old. Anybody have anything that old they could comment on? And how they finished it?

I'm also going to give that a try. Look forward to your future input on this, Matt.

Chuck, I'm curious about what kinds of wood you're using this on? It'd be a ripper on oak.

Regards,

Arturo

yup wood with tannins in it will blacken it  some with little tannins  it just adds an weathered grey look. Test first on some scrap to see if you like the outcome. you can also put a wash of tea on before to add some more tannins. i watched a cool episode on woodsmith shop where they used roon to stain a box but i cant seem to find it now.

[ffjdh]

I love the look of the vinegarooned leather but I’m having trouble finishing it afterwards.  I’d like to paint and resolene most of the items I vinegaroon.  The issue I’m having is once I re-oil the leather after vinegarooning the leather it’s hard to get paint or resolene to get a good bond and they wear or peel off easily.  Anyone have any good suggestions to deal with this?

[Klara]

On 3/1/2021 at 3:09 PM, chuck123wapati said:

Yup an air lock because you don't want wild yeasts from the air to spoil your wine. it would do no real good for roon.

Why wouldn't it? There we want hydrogen to get out and oxygen to not get in - seems a very similar situation to me (not a reason to buy an air lock, but I should have one lying around ftom my mother's wine making attempts).

@kop4 Thanks for the write-up! I didn't find it boring at all and will likely try it in the near future

 

[chuck123wapati]

3 hours ago, Klara said:

Why wouldn't it? There we want hydrogen to get out and oxygen to not get in - seems a very similar situation to me (not a reason to buy an air lock, but I should have one lying around ftom my mother's wine making attempts).

@kop4 Thanks for the write-up! I didn't find it boring at all and will likely try it in the near future

 

air locks are to keep wild yeasts out of your wine during fermentation. neither wild yeast or air has any effect on roon. its vinegar, its already been fermented, and iron the process builds some gas so just leave the lid loose.

Edited September 3, 2021 by chuck123wapati

[Klara]

kop4 wrote that we should keep oxygen, i. e. air out:

"Oxygen messes with this system. Obviously there is oxygen in the atmosphere and dissolved in your solution, and this can oxidize the iron ions – it will take them from the 2+ state to the 3+ state. Fe3+ or iron(III) is NOT what we want, because it is orange and gross and not soluble in water. If this forms, it creates an orange/brown powdery solid that sinks to the bottom of the jar. To prevent the oxidation of the iron in solution, we need to keep the pH LOW and keep the oxygen out of the system as much as possible – by not pouring or shaking the solution. "

But I admit that I was to lazy to find the air lock so I did just leave the lid on loosely. And I don't think that's the problem - but there is a problem: After 24 hours the solution just doesn't dye. One leather gets a very light grey touch, the other nothing. Maybe I didn't use enough steel wool? Does anybody have a ratio of steel to vinegar?