>>> I would characterize the situation as dry rather than greasy - I suspect it's more the salts from the sweat than any body oils that have been causing the issues. I don't find the minor discoloration particularly bad, so would the following make sense?
A4 Heavy (Periodic Cleaning)
CleanStrong-4.3
Clean-3.8
Rinse-3.0
Hydrator-3.3
Fatliquor-5.0
Protector-W+
Picture #1 shows leather damages from sweat (when read with a pH meter would shows the shifting of its pH value from 3 to 5 to much higher) and will need to be pH balance back to its chemistry pH integrity. Leather is an “amphoteric” material, that is why the fermenting sweat affects the leather protein fiber, while the other leather constituents like the tanning agents, dyestuff and fatliquor remains unchanged. The shifting ionic positive (+ve) protein fibers loses its attraction towards the ionic negative (-ve) leather constituents that leads to the denaturing of the leather that reveals as mud cracking and most possible test with dye bleeding.
>>> I suspect the Degreaser-2.2 > Acidifier-2.0 > Adhesor-73 > Aniline-76 > AnilineTop-21W would not be appropriate without a specific grease stain spot, is this correct?
Picture #2 would require the above procedure, both removing the body contact contamination, repairs and refinishing.
>>> What volumes are appropriate for each product to cover the entire sofa per application?
Each product has its specific purpose, depending on the leather condition and absorbency (just like wetting out the surface of 30 sheets of newsprint versus wetting out a glass surface), and how much required to top up: example if the fatliquor (fat and oil) content present level is 5%, it will require 10% more to do its job and if 10% will need 5% to bring it up to the optimum level. Again it may vary within the same panel as well. A leather moisture meter or its equivalent would be more precise to determine how much fatliquor will be necessary. Remember that the lifeblood of leather is the “fatliquor” (ionic negative -ve charged fat and oil). When kept at its perpetual optimum level at all time of about 15% the leather will live a very, very long time
For your readings:
Leather Approximate Quantity or Percentage of Fatliquor:
The quantities of fatliquor (fat and oil) contents retained in the leather after an universal tannery fatliquoring process may varies up from 14% to 16% depending on the leather types and it usage. This percentage drops as the fat and oil content diminishes or leaches through ageing, water, heat or chemical overexposure.
Leather rejuvenating or fatliquor replenishing is base on weight of the leather in relation to the percentage of remaining fatliquor. A simple calculation of percentage of fatliquor topping up requirement would be as follows:
If the weight of the leather in question is 100gm and fatliquor (fat and oil) content meter reading is less than 1%.
By applying 80gm of Fatliquor-5.0 to it will deliver an end result incremental of 13.3% fatliquor when dry as the 66.6% water contents evaporates.
In the leather rejuvenating Hydrator-3.3 > Fatliquor-5.0 > Hydrator-3.3 system, Hydrator-3.3 plays an important role by relaxing, opening up the inter-fibrillary spaces, facilitating and redistributing colloidal water movement, protonating and doing all the pre-conditioning work prior to fatliquoring including cleaning up any excess surface remnants to have a sticky-free surface. In practice with severe dryness the ratio for Hydrator-3.3 is 2 to 1 of Fatliquor-5.0.
It works out to be approximately 160gm of Hydrator-3.3 plus 80gm of Fatliquor-5.0 to replenish a 100gm dry leather from less than 1% back to the original tannery up from 14% to 16% fatliquor content.
In every bottle of Fatliquor-5.0 by weight content is comprises of 16.66% ionic negative (-ve) charged fat and oil, and 83.33% of water, the water content that encased the fat and oil molecule in an emulsion suspension when hydrogen bond with the ionic positive (+ve) leather protein fiber will break free and discharged clear from the leather structure to the surface.
Roger Koh
Leather Care System Formulator
Consultant / Practitioner / Instructor
web: www.leatherdoctor.com
forum: www.leathercleaningrestorationforum.com
email:
[email protected]
Roger Koh
Leather Care System Formulator
Consultant / Practitioner / Instructor
web: www.leatherdoctor.com
forum: www.leathercleaningrestorationforum.com
email:
[email protected]