Iron sulphate to colour leather black

[ScottEnglish]

A member of these forums has used a solution of iron sulphate powder and water to colour leather black. Does anyone else use iron sulphate? Would you recommend it?

I'm learning to make a simple boot. I'm concerned as to whether the solution will weaken the polyester thread I use for stitching and damage the natural crepe rubber sole if I immerse a boot in a solution of iron sulphate and water once it's assembled.

Thanks.

Edited January 27, 2023 by ScottEnglish

[ScottEnglish]

Apparently, vinegaroon/vinegar black waterproofs leather so if you wish to mould it you need to do this before immersing the leather item in to the vinegaroon. Would the same hold true for a solution of iron sulphate powder and water?

Thanks.

[TomE]

I don't think iron sulfate is very reactive.  It is unlikely to damage polyester thread. Hasluck ("Harness Making" 1904) describes making black dye. "The dye or stain is made by boiling together for half an hour 1 lb logwood chips, 4 oz crushed nutgalls, 1/2 lb copperas, a little gum arabic, and 5 qt of water.  Keep a little in an old bottle hung near the bench.  The dye is applied with a stick having a piece of felt attached to its end.  The ink can be thinned by the addition of water."

[Tugadude]

1 hour ago, ScottEnglish said:

Apparently, vinegaroon/vinegar black waterproofs leather so if you wish to mould it you need to do this before immersing the leather item in to the vinegaroon. Would the same hold true for a solution of iron sulphate powder and water?

Thanks.

Where did you see this?  Personally, I would tend to doubt that it "waterproofs" at all.   Waterproofing tends to be either an impenetrable coating such as a sealer or an integral treatment such as oil, wax, etc.   

[Dwight]

39 minutes ago, Tugadude said:

Where did you see this?  Personally, I would tend to doubt that it "waterproofs" at all.   Waterproofing tends to be either an impenetrable coating such as a sealer or an integral treatment such as oil, wax, etc.   

I'm gonna get in here . . . simply because Tandy seems to have done away with their oil base dye . . . nothing but USMC black . . . which I'm going to throw away.   WAYYYY to much buffing needed to make it work . . . 

Need someone to school me on vinegaroon  . . . how is is made . . . how is it kept . . . how to apply it . . . what extra steps are necessary to make it work and not damage my leather????

Thanks, may God bless,

Dwight

[chuck123wapati]

2 hours ago, ScottEnglish said:

Apparently, vinegaroon/vinegar black waterproofs leather so if you wish to mould it you need to do this before immersing the leather item in to the vinegaroon. Would the same hold true for a solution of iron sulphate powder and water?

Thanks.

so far I haven't found anything that truly water proofs leather. Vinegar sure doesn't do it it is 96% water. i use the roon all the time.

[chuck123wapati]

8 minutes ago, Dwight said:

I'm gonna get in here . . . simply because Tandy seems to have done away with their oil base dye . . . nothing but USMC black . . . which I'm going to throw away.   WAYYYY to much buffing needed to make it work . . . 

Need someone to school me on vinegaroon  . . . how is is made . . . how is it kept . . . how to apply it . . . what extra steps are necessary to make it work and not damage my leather????

Thanks, may God bless,

Dwight

put vineagar and clean steel wool, or any clean iron, in a glass jar until the wool is gone or a week or so at least, apply it just as any dye. You can stain wood with it also just paint your wood with tea then apply the roon, the black color comes from the chemical reaction between the iron and tannic acid that leather is tanned with. tea also has tannic acid. then folks neutralize the vinegar with baking soda water mix. 

 

[327fed]

Won’t rot thread. Very weak acid. Can neutralize it with baking soda and water. Don’t really matter how much. Makes leather harden a bit for me, more than wet molding. Leather will stink for about 2  weeks. Sealer covers the smell mostly. Will freeze and break your jars, otherwise seems stable. I do 2 coats to get a deep black. Looks kinda gray till you oil it. 

[ScottEnglish]

Thanks everyone for your replies. For those who asked about my source regarding vinegaroon waterproofing leather here it is: https://www.adamsleatherworks.com/post/vinegaroon-a-k-a-vinegar-black See under subheading Worth mentioning. They actually say vinegaroon makes leather more water resistant. I was incorrect in saying waterproof.

 

 

[Tugadude]

7 minutes ago, ScottEnglish said:

Thanks everyone for your replies. For those who asked about my source regarding vinegaroon waterproofing leather here it is: https://www.adamsleatherworks.com/post/vinegaroon-a-k-a-vinegar-black See under subheading Worth mentioning. They actually say vinegaroon makes leather more water resistant. I was incorrect in saying waterproof.

 

 

Thanks for that!  And thanks for not getting defensive!  We're all trying to learn here and I have much to learn from the rest of you.  

[TomE]

The "copperas" in the Hasluck recipe above is iron sulfate crystals.  He adds "log chips" and "gall nuts" that I guess are for tannins.  The "gum arabic" is polysaccharide and probably helps with slicking the edge.  Old school recipe. 

@Dwight of course you can buy Fiebing's pro black dye from their online store or from Springfield Leather, etc.  There is something different about black pro dye compared with the browns I use more often.  The black tends to dry out the leather more (oiling fixes it), and I notice an oily residue (not seen with the browns) when I rinse the dauber with water. 

[ScottEnglish]

Thanks for telling me what copperas are TomE. Now I realize why you included Hasluck's recipe in your post.

[Dwight]

4 hours ago, TomE said:

 

@Dwight of course you can buy Fiebing's pro black dye from their online store or from Springfield Leather, etc.  There is something different about black pro dye compared with the browns I use more often.  The black tends to dry out the leather more (oiling fixes it), and I notice an oily residue (not seen with the browns) when I rinse the dauber with water. 

I got the impression they were not making it any more . . . I used it for the last 15 or more years . . . had a black project last month . . . USMC was all they had.

I'd probably give it to someone who drove over to pick it up.

For now . . . I just might jump on the vinegaroon band wagon . . . still "contemplating" . . . but thanks . . . I'll check into Springfield Leather as well.

May God bless,

Dwight

[TomE]

3 hours ago, Dwight said:

I got the impression they were not making it any more . . . I used it for the last 15 or more years . . . had a black project last month . . . USMC was all they had.

I'd probably give it to someone who drove over to pick it up.

For now . . . I just might jump on the vinegaroon band wagon . . . still "contemplating" . . . but thanks . . . I'll check into Springfield Leather as well.

May God bless,

Dwight

Fiebing's online shop lists  black Pro Dye in 4oz, quarts, and gallons.   I found this old harness maker's manual with recipes for many different "blacking" dyes (Chapter XXV). https://upload.wikimedia.org/wikipedia/commons/8/80/The_harness_makers'_illustrated_manual._A_practical_guide_book_for_manufacturers_and_makers_of_harness%2C_pads%2C_gig_saddles%2C_etc._.._(IA_cu31924000022636).pdf  It's a fun read if you're easily entertained like me.

[Dwight]

2 hours ago, TomE said:

Fiebing's online shop lists  black Pro Dye in 4oz, quarts, and gallons.   I found this old harness maker's manual with recipes for many different "blacking" dyes (Chapter XXV). https://upload.wikimedia.org/wikipedia/commons/8/80/The_harness_makers'_illustrated_manual._A_practical_guide_book_for_manufacturers_and_makers_of_harness%2C_pads%2C_gig_saddles%2C_etc._.._(IA_cu31924000022636).pdf  It's a fun read if you're easily entertained like me.

Thanks TomE

May God bless,

Dwight

[ScottEnglish]

I've used a solution of water and iron sulphate to successfully colour natural veg tan leather. It does work. I presumed it did as a member of these forums said they use it instead of vinegaroon. The final colour is black with a hint of grey. If leather is immersed in a weaker solution or for a shorter duration the colour is grey with a hint of blue. I understand from the aforementioned forum member that unlike vinegaroon it's necessary after colouring leather in this way to wash it in water to remove weak sulphuric acid.

 

[Matt S]

22 hours ago, ScottEnglish said:

I've used a solution of water and iron sulphate to successfully colour natural veg tan leather. It does work. I presumed it did as a member of these forums said they use it instead of vinegaroon. The final colour is black with a hint of grey. If leather is immersed in a weaker solution or for a shorter duration the colour is grey with a hint of blue. I understand from the aforementioned forum member that unlike vinegaroon it's necessary after colouring leather in this way to wash it in water to remove weak sulphuric acid.

 

Black strikers like iron sulphate and vinegaroon give a darker or lighter effect based on the amount of tannin left in the leather. There's a chemical reaction which occurs within the leather where tannic acid oxidises the iron in the iron-containing solution into black iron tannate. The less tannic acid left in the leather after tanning the less pronounced the effect. Tannins (and so the blacking effect) can be increased, usually with a solution of black tea. In South America they strike rawhide black using this method (rawhide, being untanned, has no tannins). Solution strength and contact time also affect how deep a shade is produced.

It's not unusual for black-struck leathers to look blue-grey until some grease or oil is added.

I think that there may also be some variation based on how much grease/oil is in the leather, as that would reduce the ability of a water-based solution to contact the leather fibres. Even natural/russet/tooling leather often has a small amount of oil or grease added during production.

[ScottEnglish]

Thanks for your post Matt S. I'm not the sharpest knife in the drawer and struggled at school. But your above explanation of the science is straightforward. Thanks for taking the time to enlighten me. And I trust others also.

Scott

[Doc Reaper]

On 2/15/2023 at 5:38 AM, ScottEnglish said:

Thanks for your post Matt S. I'm not the sharpest knife in the drawer and struggled at school. But your above explanation of the science is straightforward. Thanks for taking the time to enlighten me. And I trust others also.

Scott

Then I need someone to look at this and help me understand what happened. I purchased the   $10 bag of iron sulfate, added it to a 3/4 full jar (Libby’s chicken gravy jar) of water, I used 2 jar lids full of the iron sulfate. All I got was a light gray in return, it turns medium dark gray with neatsfoot oil. I’m experimenting with the iron sulfate (30%) while I was also checking out my one week old vinegaroon and just one drop of the roon dropped onto the iron sulfate test strip, it turned it dark blue in the blink of an eye. While both mixtures took a bit of time to color the leather the two coming together was like wow fast! The picture shows 2 strips - both test strips are test for the iron sulfide. The round mark is where the drop of groon landed by chance

Edited February 21, 2023 by Doc Reaper
Grammer

[ScottEnglish]

Hi Doc Reaper. Matt S is the fellow you need a post from.

My initial experience of a solution of iron sulphate and water was disappointing until I increased the amount of iron sulphate in the solution. I left the scraps of leather soaking in the solution for several hours.

Matt S said something about black tea in combination with the iron sulphate solution making it more effective. Hopefully, he will help us out.

[Gosut]

With iron call ink, made from ferrous sulfate and a tannic acid solution, the resulting reaction doesn't immediately turn black. Instead, it turns black over time as it oxidizes. For this reason, some iron gall ink recipes added a coloring agent as a "stand in" until the ink darkened. I don't know if this same thing happens in leather. Unlike paper and parchment, it's likely to be harder for it to oxidize in leather.

[Doc Reaper]

I scrapped the 30% iron sulfate solution. I’m guessing the chemical mixture of the iron sulfate mixed with water is too weak of a solution. I’m going back to play with the vinegaroon, I get faster results with it!

[ScottEnglish]

I used a solution of iron sulphate powder and water to colour a pair of my simple boots black. They'd previously been dyed dark chocolate with Fiebing's Pro Dye. For some reason the dye kept rubbing off the leather. So I decided to colour them black using a solution of iron sulphate powder and water. But after several months the leather on my boots is literally rotting! It's cracking and breaking apart.

The only explanations I can think of are that the solution of iron sulphate powder and water, despite rinsing and soaking the leather in water after colouring it black, was too acidic and some remained in the leather causing it to rot, or that there was a reaction between the remains of the Fiebing's Pro Dye and the solution of iron sulphate powder and water.

I've made several pairs of simple boots before using the same type of leather, natural vegetable-tanned, and never had this problem.

What are people's thoughts please?

Thanks.

[dikman]

Maybe should have washed it off with a baking soda solution to neutralize it?

[tsunkasapa]

Has anyone bothered to check the Ph of the solution? Here is a quote from Wikipedia;

Iron(II) sulfate is sold as ferrous sulfate, a soil amendment^[20] for lowering the pH of a high alkaline soil so that plants can access the soil's nutrients.

This would lead one to assume that it is an acidic compound, hence needing to be neutralized.