Author Topic: Vinegaroon and other "Traditional" Leather Dyes  (Read 55763 times)

Offline Mad Monk

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Re: Vinegaroon and other "Traditional" Leather Dyes
« Reply #25 on: May 12, 2010, 06:42:59 AM »
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Logwood, as a dye, was considered to be one of the few plant dyes that proved to be colorfast to sunlight exposure. 


Logwood was known as a very unstable and extremely light sensitive dye. At one point it was outlawed from usage in England and by name forbidden in Federal uniform regulations by mid 19th century, due to it's quick fading properties. Colorfast it most definately isn't. I've had logwood dyed cloth fade from dark gray to light tan within 14 days of repeated sulight exposure.

It all depends on how you use it.

It was first used in England without a mordant.  A decree was passed in 1581 prohibiting the use of it in that country.  The reasons given were to foster sales of woad grown locally and to inhibit the use of an impermanet dye.
In 1619 a proclamation for Prevention and Restraint of the Abuses and Inconveniences Occasioned by Dying with Logwood was issued.  In 1661 the law was lifted.

Logwood was used as a black dye in England into the 1950's and industrially in the U.S. into the 1970's.  Used in the U.S. to dye typewriter ribbons and to color leather.

Logwood with mordants had been used on wool.

As a replacement for Indigo it was a total failure.

Bill k.

Offline Chuck Burrows

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Re: Vinegaroon and other "Traditional" Leather Dyes
« Reply #26 on: May 12, 2010, 07:13:42 AM »
Clark - Dying leather and dying cloth are generally two completely different things (in fact even dying cloth is different dependent on the dye) and comparing the two directly can be frstrating at best. For instance in general leather does not need a mordant since tannin is itself a mordant. On the other hand there are differences in tannins:

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The Two Types
There are two types of tannin: Catechol  and Pyrogallol.. By understanding when to blend these together, the expert tanner could reputedly create the appropriate leather for any need: hard and firm, mellow and soft, light or heavy. Until you are an expert and can even notice the differences, I wouldn't worry about it, but it is interesting to pay attention to as you tan.

Catechols (aka condensed) are more astringent and tan more quickly than the pyrogallols. They deposit a reddish sediment known as 'reds' or phlobaphenes. They make leathers of pink, red or dark brown hues, that are more 'solid'. They also create greenish-black spots on contact with iron. Mimosa, birch, hemlock, quebracho, alder and fir bark contain catechols. Oak bark contains both types.

Pyrogallols (aka hydrolysable) deposit a pale-colored sediment called 'bloom' (elegiac acid} which, if deposited in the leather, improves its solidarity, wearing properties and resistance to water. Hence they are favored for sole leather. They are also preferable for leathers intended for bookbinding, upholstery and other purposes where longevity is essential. The resultant leather is of pale color varying from creamy or yellowish to light brown. Pyrogallols make bluish-black spots on contact with iron and resist changes in pH value. Sumac, chestnut, oak galls and oak-wood contain pyrogallols.

source: http://braintan.com/barktan/2tannins.htm

The following article discusses the problems dying black using hemlock tanned leather versus oak tanned leather - this appears to be due to the differences in the tannins noted above and may shed some light on why import hides at times have problems when using vinegar black. On the other hand I've never had any real problems getting a decent to good black even with import hides and have never had the problems that Stophel noted......
http://www.jarnaginco.com/cmharticle.pdf

As for logwood and leather - yes it is generally good for browns as is, for black it takes a bit more - just one recipe from the past I have is:
"Boil a quantity of logwood bark in double it's bulk of rain water (i.e. water that hasn't been tainted with minerals) for two or three hours, then strain off. Add 1/4 pound of potash to 2 gallons of the logwood liquor."
Note teh use of potash - a base like baking soda. In fact baking soda alone (or other stronger bases such as washing soda or potash) will darken leather, but I find that used alone they tends to "burn" the leather too easily when not carefully applied and that can be just a matter of seconds.

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Normally tanned leather is rather stiff and hard.  To make leather soft and supple they used to run it through a process known as "stuffing".  The hides were thrown into a revolving drum.  A non-oxidizable oil was added to the hides.  The oil then worked its way into the hides as they tumbled.  The oil makes the hides pliable.  Acting as an "internal lubricant" in the porous structure of the leather.  This also acts to waterproof the hides when they are made up into finished goods.

Thanks for your info Bill and it's still called stuffing. There are in fact two methods generally used, hot stuffing and regular stuffing aka fat liquoring. In period some of the most common oils used were: fish oil, neats foot oil, and tallow - beef and sheep mostly, although hog lard (aka pig tallow) was also used.
re: neats foot oil - originally rendered from the shin bones of neats aka cattle. Since the 1930's though neats foot oil made in the USA can be made from other sources (mostly hog lard these days per one of the major the manufacturers) as long as it's meets a certain Mil-Spec standard.
The "problem" with all oils in leather though is over time they either get "pushed out" to the surface due to water, sweat, and other factors so the leather drys out and gets damaged. In fact most dyes, especially modern ones that so often use thinners such as alcohol, toluene, etc. dry out, stiffen, and crack after application and why re-oiling/condtioning is necessary.
these links have some info of interest as well:
http://www.jarnaginco.com/leather%20definitions%20index.htm

http://www.hermannoakleather.com/




« Last Edit: May 12, 2010, 07:19:01 AM by ChuckBurrows »
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Offline Mad Monk

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Re: Vinegaroon and other "Traditional" Leather Dyes
« Reply #27 on: May 12, 2010, 06:20:59 PM »
Chuck,

A couple of points here.
You mention Hemlock as a tanbark.  When I did the reading of the tech books at work they mentioned that the tanbark of choice simply depended on where the particular tannery was located.  Around here they usedChestnut as their first choice and then oak as the second choice.  The bundles of tanbark were known as "shales" of tanbark.  The tanneries in upstate New York used Hemlock simply because oak and chestnut were not common trees up there.

The bark of oak yields both tannic acid and gallic acid.  In some acorn caps the level of gallic acid is very high compared to the level of tannic acid.  In effects produced the gallic acid was considered to be about 3 times stronger than tannic acid.

The tech book described the process in a roughly mid-19th century tannery.  The actual tanning was done usually in 4 "pits".  The first pit had a weak tannic acid solution in it.  Then as you went to tank #2, then tank #3 and finally tank #4 the concentration of tannic acid increased in each tank.  If you soaked the hide initially in a strong tannic acid solution the surface of the hide would become very hard and it would be nearly impossible to tan deeper into the hide.

In the pre-1900's tanning process there was the dunging step before tanning the leather.  That step added some coloring matter to the hide.  And different tanneriers had different ideas of which dung to use.
Then the wood selected as the source for tannic acid added coloring to the hide.  According to the tech book the hemlock used in New York state tanneries added a red coloring to the finished leather.  The red coloring not being seen in oak bark tanning.

The tech book went into the dunging thing a bit.  The hide picked up extra sulfur ions from the dunging process.  This also helped the leather pick up more tannins in the tanning step.

Neats foot oil.
The original source for neats foot oil was the cushiony pads in the hoofs of the livestock.  In the hoof is sort of a sack that would yield this oil.  The pad acting to cushion the shock when the hoof hit the ground if the animal was running.  Sort of like gel pads in a running shoe.  Trouble is that a hoof does not yield a lot of ths oil.

You mentioned the use of "potash".
Leather, horn, wool, etc., are "acid" materials.  Hitting them with a strong caustic degrades them.  I once tried boiling out horn cores in a bath of water and potash, potassium carbonate.  The horns became very brittle and fragile.  When I dropped one on the cement walk it shattered.
Potash was one of the earliest exports of the American colonies.  Due to the vast forests of hardwood trees.  Know in international trade as "American ashes" for about 200 years.
The tech books did not go into great detail on this but I think that sometimes potash was used to partially saponify some of the oils or fats used to stuff the leather to make them penetrate into the leather better than if just used alone.

I never thought that the tanning process was so long and tricky until I read the tech books on the old processes used to make leather.

Bill K.

Offline Chuck Burrows

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Re: Vinegaroon and other "Traditional" Leather Dyes
« Reply #28 on: May 13, 2010, 12:27:41 AM »
Thanks Bill for the added info - yep and dunging or bating is still done although what they use for the process today I'm not sure. Hermann Oak Leather
 (http://www.hermannoakleather.com/) shows the overall process they currently use and the bating cycle is used to re-acidy/remove the lime from  the leather and to add enzymes.

For those interested in the historical aspects, here are a couple of 19th Century treatises on tanning and leather manufacturing:

the first is from 1813:
http://books.google.com/books?id=6_oGAAAAQAAJ&printsec=frontcover&dq=circle+of+mechanical+arts&cd=1#v=onepage&q&f=false

The second 1898:
http://books.google.com/books?id=UhAAAAAAMAAJ&pg=PA188&lpg=PA188&dq=%22the+leather+manufacturer%22&source=bl&ots=b5sPc_utzW&sig=MHkeuBzzxVLwqSZXZ4wsPGe5kic&hl=en&ei=phzrS4vMB4G6swOysaTNDw&sa=X&oi=book_result&ct=result&resnum=7&ved=0CDkQ6AEwBg#v=onepage&q&f=false
« Last Edit: May 13, 2010, 12:28:32 AM by ChuckBurrows »
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Offline TPH

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Re: Vinegaroon and other "Traditional" Leather Dyes
« Reply #29 on: May 13, 2010, 03:57:43 PM »
Excellent links Chuck, thanks for posting them. In the first, "The Circle of Mechanical Arts", I'm sure everyone also noted the chapter on "Gun-making", a good article on the gun maker's art as practiced in England at the time. At that time, nobody did it better.
T.P. Hern

Offline Spotted Bull

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Re: Vinegaroon and other "Traditional" Leather Dyes
« Reply #30 on: June 25, 2010, 05:10:03 PM »

 In fact baking soda alone (or other stronger bases such as washing soda or potash) will darken leather, but I find that used alone they tends to "burn" the leather too easily when not carefully applied and that can be just a matter of seconds.


How about a diluted solution, Chuck?  If the pH is kept to around 9 to 9.5, wouldn't that be low enough to allow a reaction, but still give enough time to apply a very mild acid to neutralize the burn? 

Just as thought from someone most recently employed as a chemical water treatment specialist, does anyone ever check the pH of the solutions they use, and if so what are the ranges of both the acid and base washes used?


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Re: Vinegaroon and other "Traditional" Leather Dyes
« Reply #31 on: June 25, 2010, 07:02:40 PM »
There's so much GOOD STUFF in this thread, I wonder if there is some way to preserve it and keep it readily accessible for future reference? 

Thanks to all who have responded, and all else who contribute.  I feel like I'm going to school again, but I'm certainly paying better attention this time around!   ;D

Offline T.C.Albert

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Re: Vinegaroon and other "Traditional" Leather Dyes
« Reply #32 on: June 25, 2010, 07:21:18 PM »
Roaringbull...not to step in out of turn, but I will answer that in my experience,
even diluted caustic salt type solutions that are still strong enough to darken the leather, seem to penetrate the leather very very quickly, where the water evaporates as the leather dries, thus concentrating the salts which stay deep "in" the leather...eventually degrading the leather like salts etc usually do...as simple as it seems, its actually pretty touchy stuff when used on leather... To me it seems kind of like using a good though slightly wet pair of nice dress leather gloves to throw rock salt on a frosty lane before church on a cold Sunday morning...even if you only throw a few handfulls, and even if you throw it really fast, theres a good chance you will see serious damage to the gloves by spring time if not sooner... :o

thats been my experience anyhow, but maybe neutralizing it etc with different techniques would give better results?
TCA  
« Last Edit: June 25, 2010, 07:36:14 PM by T.C.Albert »
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Offline Spotted Bull

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Re: Vinegaroon and other "Traditional" Leather Dyes
« Reply #33 on: June 25, 2010, 08:02:07 PM »
well I'm far from an expert but you make a great point with the salts...which could cause an exothermic reaction if you did try and neautralize it with a acid of the wrong type, or even rinse it with water.

Think I'll just stick with the time-honored methods!! ;D