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For those of you interested in Confederate or 19th century leather, David Jarnagin and I will finally have our article (CONFEDERATE LEATHER, BLACK OR BROWN, HOW AND WHERE?) published on the subject in the August issue (we are told) of the NORTH SOUTH TRADER’S MAGAZINE.
There has been a lot of new research lately on 19th century leather that may be of interest to some of you. We have had one other leather article published in the Company Journal of Military Historians (Hemlock Leather- The Federal Ordnance Department’s Other War. Journal of the Military Collector & Historian, The Company of Military Historians, Washington DC., Vol. 57, No. 1 -- Spring 2005) and more are in production.
For further interest, I enclose a “brief” excerpt from a web site that has some excellent information on 19th century vegetable tanned leather. It also contains useful tid bits on its care that is applicable to collectors and reenactors today. While this was somewhat common knowledge at least among tanners and some military ordnance officers of the period, it has largely been lost due to the advance of technology and the effects of time. The site contains some excellent before/after photos and even an excerpt from a military manual on leather care. The rules of this forum prevent us from providing a link but if your interested, with a little effort I am sure you can find it or, failing that, contact me by private message.
MODERATORS: Please leave this up. We are posting it as a means to promote an important new research article and for informational purposes only. It is not meant in any way to be an advertisement of non- approved vendor products
Ken R Knopp
-----------------------------------------
(EXCERPT.....)
This is a very brief discussion of the damage that can be caused by the loss of moisture in vegetable tanned leather.
Leather Tanned Prior to 1890:
Today leather is sold by square foot but until the mid 1880’’s leather was sold by weight. Due to the fact that higher weight brought a higher price, tanners used every means available to increase weight. One of the most inexpensive ways to increase weight was to impart high quantities of tannins. This overuse of tannin can cause brittleness and cracking of the grain surface so more oils were needed to offset the additional tannins. Many original examples are now showing the damage that the overuse of the tannin and oils have caused.
After the leather was tanned a protective finish was applied to protect the leather surface which was required by the Ordnance Department. This finish contained waxes and oils which sealed the grain surface and prevented the oil from oxidation. As long as the finish remained on the surface the oils were held in to keep the grain surface lubricated and it remained soft and pliable. As the leather aged the finish was worn away and the oils were allowed to oxidize and penetrate into the fibers. This left the grain surface unprotected and it would dry out and would begin to crack and flake. The Ordnance Dept was apparently aware of this as there is record of the acquisition of polishes.
Aging Theory: I have discussed this condition with several tanners and we have come to this theory: We believe that as the finish wears away and the oils are allowed to oxidize using the available moisture in the grain surface; which makes the surface dry out and begin to cup. This cupping process is caused by the grain drying out faster than the fibers underneath. As the grain surface shrinks it will eventually tear itself loose or flake off. (A good mental picture: the ground when the surface has dried rapidly and begins to crack and cup)
The flaking and cracking of the drying out process is sometimes diagnosed as ““acid rot””, a condition caused by acids actually decaying the leather rather than a drying process. The two appear very similar.
A good wax will protect the moisture in the grain stopping this cracking and flaking process caused by lack of moisture
The information below will help you understand the aging process of leather.
The first thing to remember is that leather is skin (from a cow, horse, pig, or goat and etc.) that has undergone a tanning process to make it "decay resistant" along with imparting qualities of strength, flexibility and overall appearance. This was done by the tanner to give a certain number of years of good use from that piece of leather. What makes a leather item last longer than another is the care and feeding that it was given by its owner. This care and feeding is very important. For years the debate has raged about which product to use to treat leather. Some say do nothing and others say to oil the leather at least once a year. So what is the best thing to do?
Moisture: This is the most important point in leather care. All changes in leather are due to moisture differences. If too much moisture is lost leather becomes very hard and brittle. Water is the best lubricant; but it can be lost so some oil must be used in order to maintain a soft supple grain surface. When the leather was originally tanned the tanners oiled (cod) as a medium-term lube and (tallow) as a long term lube. Moisture can play another role if the climate is moist then mold can form on the leather surface. (see information on mold below)
Oils: Catch 22. It seems logical to lubricate the leather with oil to make it soft when in fact adding oil can cause damage. Oil is necessary in leather. Oil acts as a lubricator in the leather fibers. The oil in the fibers allows them to side over each other without causing damage to the fibers. The problem is when too much oil is used this stops the leather from being able to breathe. As humidity goes up and the leather adsorbs moisture if too much oil has been used the excess moisture will not be allowed to escape and this will start the leather to rot. Remember when it comes to leather a little oil is good but a lot is very bad. Oil used in a large quantity weakens the tensile strength of the leather fibers. This can occur with as little as 21% oil content in the leather. Leather coming from the tannery has an oil content of only 16 to 19%. The best guess I have is to keep the oil content under 30% overall.
Oxidation: How oil penetrates is through oxidation. All oils will oxidize over time. It just depends on the type of oil and conditions to how long this process takes. See Notes at the bottom of the page.
Oil softens the leather by changing the shape and placement of the fibers. Oil penetrates the fibers causing them to distend and swell. Some of the fibers will move out of the tightly packed order into a looser order. This is what makes the leather soft. These physical changes in the leather cause it to become weaker and weaker. This process is irreparable. I have seen this in shoes that have been oiled to the extent that the leather began to crack and tear. Over oiling is one of the worst things you can do to leather. Remember, a little oil goes a long way.
Please do not use any oils that contain mineral oils or listed as petroleum distillates. This type of oil over time breaks down into a solvent, and since solvent can de-tan, you get double damage. If you must oil, use natural oil like "pure Neatsfoot" or a good grade of tallow. Please read the labels of any thing you apply to leather very carefully. Leather does require oil but most do not know how to oil, and this is very important.
How do you protect your leather: The grain surface takes the most damage from the loss of moisture. The best way to protect it is to maintain a polish on the surface that will seal and protect the moisture in the leather fibers from drying. A specially formulated wax finish would be the best. You should apply the wax at least twice a year, and maybe more if the items are used heavily. When at least 50% of the original finish is present I would recommend a clear wax. When applying the finish on leather that is beginning to flake or crack there may be some flakes that come off during the application of the wax. The original lamp black in the black wax may rub off so for the best protection a coat of clear wax should be applied over the black wax. Multiple coats may be applied with a waiting period of one day between coats.
There has been a lot of new research lately on 19th century leather that may be of interest to some of you. We have had one other leather article published in the Company Journal of Military Historians (Hemlock Leather- The Federal Ordnance Department’s Other War. Journal of the Military Collector & Historian, The Company of Military Historians, Washington DC., Vol. 57, No. 1 -- Spring 2005) and more are in production.
For further interest, I enclose a “brief” excerpt from a web site that has some excellent information on 19th century vegetable tanned leather. It also contains useful tid bits on its care that is applicable to collectors and reenactors today. While this was somewhat common knowledge at least among tanners and some military ordnance officers of the period, it has largely been lost due to the advance of technology and the effects of time. The site contains some excellent before/after photos and even an excerpt from a military manual on leather care. The rules of this forum prevent us from providing a link but if your interested, with a little effort I am sure you can find it or, failing that, contact me by private message.
MODERATORS: Please leave this up. We are posting it as a means to promote an important new research article and for informational purposes only. It is not meant in any way to be an advertisement of non- approved vendor products
Ken R Knopp
-----------------------------------------
(EXCERPT.....)
This is a very brief discussion of the damage that can be caused by the loss of moisture in vegetable tanned leather.
Leather Tanned Prior to 1890:
Today leather is sold by square foot but until the mid 1880’’s leather was sold by weight. Due to the fact that higher weight brought a higher price, tanners used every means available to increase weight. One of the most inexpensive ways to increase weight was to impart high quantities of tannins. This overuse of tannin can cause brittleness and cracking of the grain surface so more oils were needed to offset the additional tannins. Many original examples are now showing the damage that the overuse of the tannin and oils have caused.
After the leather was tanned a protective finish was applied to protect the leather surface which was required by the Ordnance Department. This finish contained waxes and oils which sealed the grain surface and prevented the oil from oxidation. As long as the finish remained on the surface the oils were held in to keep the grain surface lubricated and it remained soft and pliable. As the leather aged the finish was worn away and the oils were allowed to oxidize and penetrate into the fibers. This left the grain surface unprotected and it would dry out and would begin to crack and flake. The Ordnance Dept was apparently aware of this as there is record of the acquisition of polishes.
Aging Theory: I have discussed this condition with several tanners and we have come to this theory: We believe that as the finish wears away and the oils are allowed to oxidize using the available moisture in the grain surface; which makes the surface dry out and begin to cup. This cupping process is caused by the grain drying out faster than the fibers underneath. As the grain surface shrinks it will eventually tear itself loose or flake off. (A good mental picture: the ground when the surface has dried rapidly and begins to crack and cup)
The flaking and cracking of the drying out process is sometimes diagnosed as ““acid rot””, a condition caused by acids actually decaying the leather rather than a drying process. The two appear very similar.
A good wax will protect the moisture in the grain stopping this cracking and flaking process caused by lack of moisture
The information below will help you understand the aging process of leather.
The first thing to remember is that leather is skin (from a cow, horse, pig, or goat and etc.) that has undergone a tanning process to make it "decay resistant" along with imparting qualities of strength, flexibility and overall appearance. This was done by the tanner to give a certain number of years of good use from that piece of leather. What makes a leather item last longer than another is the care and feeding that it was given by its owner. This care and feeding is very important. For years the debate has raged about which product to use to treat leather. Some say do nothing and others say to oil the leather at least once a year. So what is the best thing to do?
Moisture: This is the most important point in leather care. All changes in leather are due to moisture differences. If too much moisture is lost leather becomes very hard and brittle. Water is the best lubricant; but it can be lost so some oil must be used in order to maintain a soft supple grain surface. When the leather was originally tanned the tanners oiled (cod) as a medium-term lube and (tallow) as a long term lube. Moisture can play another role if the climate is moist then mold can form on the leather surface. (see information on mold below)
Oils: Catch 22. It seems logical to lubricate the leather with oil to make it soft when in fact adding oil can cause damage. Oil is necessary in leather. Oil acts as a lubricator in the leather fibers. The oil in the fibers allows them to side over each other without causing damage to the fibers. The problem is when too much oil is used this stops the leather from being able to breathe. As humidity goes up and the leather adsorbs moisture if too much oil has been used the excess moisture will not be allowed to escape and this will start the leather to rot. Remember when it comes to leather a little oil is good but a lot is very bad. Oil used in a large quantity weakens the tensile strength of the leather fibers. This can occur with as little as 21% oil content in the leather. Leather coming from the tannery has an oil content of only 16 to 19%. The best guess I have is to keep the oil content under 30% overall.
Oxidation: How oil penetrates is through oxidation. All oils will oxidize over time. It just depends on the type of oil and conditions to how long this process takes. See Notes at the bottom of the page.
Oil softens the leather by changing the shape and placement of the fibers. Oil penetrates the fibers causing them to distend and swell. Some of the fibers will move out of the tightly packed order into a looser order. This is what makes the leather soft. These physical changes in the leather cause it to become weaker and weaker. This process is irreparable. I have seen this in shoes that have been oiled to the extent that the leather began to crack and tear. Over oiling is one of the worst things you can do to leather. Remember, a little oil goes a long way.
Please do not use any oils that contain mineral oils or listed as petroleum distillates. This type of oil over time breaks down into a solvent, and since solvent can de-tan, you get double damage. If you must oil, use natural oil like "pure Neatsfoot" or a good grade of tallow. Please read the labels of any thing you apply to leather very carefully. Leather does require oil but most do not know how to oil, and this is very important.
How do you protect your leather: The grain surface takes the most damage from the loss of moisture. The best way to protect it is to maintain a polish on the surface that will seal and protect the moisture in the leather fibers from drying. A specially formulated wax finish would be the best. You should apply the wax at least twice a year, and maybe more if the items are used heavily. When at least 50% of the original finish is present I would recommend a clear wax. When applying the finish on leather that is beginning to flake or crack there may be some flakes that come off during the application of the wax. The original lamp black in the black wax may rub off so for the best protection a coat of clear wax should be applied over the black wax. Multiple coats may be applied with a waiting period of one day between coats.
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