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Thread: Any hope for this 15 year old never cleaned nubuck sofa?

  1. #1
    Join Date
    Jun 2021
    Posts
    2

    Default Any hope for this 15 year old never cleaned nubuck sofa?

    I have this sofa that has never been cleaned before, it has numerous stains, including a very recent cat urine stain which is the biggest offender.


    Photo shows initial cat urine stain, after I immediately applied white vinegar by dabbing with cloth.


    Photo shows the stain after 24 hours, I laid a paper towel on it and put plastic on it.

    Is there any hope at all for this couch? Any advice would be greatly appreciated, I am quite devastated by this, as it is a very expensive couch with sentimental value.

  2. #2
    Join Date
    Feb 2007
    Location
    Greater Vancouver, Canada.
    Posts
    5,102

    Default

    Here is the leather problem-solving guide for Nubuck
    Name:  nubuck2-n-.jpg
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    And this is the recommended kit
    Name:  Kit-N5.uk__01717.1588467963.jpg
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    And the link to Kit-N5.uk
    https://www.leatherdoctor.com/leathe...ler-kit-n5-uk/

    Here are tips for urine
    Tips on Urine:

    Urine is a compound waste discharge, comprised of urochrome, uric acid, and ammonium salt to deal with. When deposited urine attracts the natural bacteria from the atmosphere and starts to ferments, a putrid odor will develop from the protein component of the urine and ammonic odor will develop from the ammonium salt. When ammonic odor becomes present, the pH of the contamination would have shifted to 10. Such high pH above the neutral average 3 to 5 of leather causes the amphoteric protein fiber to shift ionic negative (-ve); that causes the protein fibers to repels its other ionic negative (-ve) constituents like the tanning agent, fatliquor, and dyestuff. Behaving just like the attraction of a magnet, like poles repel. When the leather constituent breaks hydrogen bond with the protein fiber, the leather starts to denature and revert to rawhide. A typical appearance of an aged or compounded contamination is a darkening effect from the fugitive tanning agents, a whitening effect from the fatliquor. Fugitive dyestuff or bleeding is only apparent from a white towel detection and yellowing from the urochrome. The denaturing or reverting to the rawhide effect of the leather is further confirmed by tackiness or in worst-case sliminess in the presence of moisture. The leach-out fatliquor results in stiffness and fugitive dyestuff results in discoloration. A systematic sequence of decontamination approach includes surface residue removal with CleanUrine-1.5 (pH 1.5), and rinse with Acidifier-2.0 (pH 2.0) recharging the protein fiber ionic positive (+ve) and neutralizing the ammonium salt with KillUrine-2.1 (pH 2.1). Utilizing such a low pH treatment retards bacteria activities from off-gassing putrid odors, a natural pH control without the need to use bactericide or fungicide for mold prevention. Therefore, urine is a type of soiling that will require a biochemistry approach to decontaminate it. Restoring the leather begins after decontamination with Hydrator-3.3, a pH 3.3 multifunctional product that has ionic positive (+ve) charging abilities, an active surfactant essential for foreign water movement within the inter-fibrillary spaces to redistribute the leather constituents and purging foreign contamination to resurface. This is the last of the wet cleaning process to remove suspended urochrome yellowish compounds through visible white tissue paper as an extension of the leather in the wicking process as the leather dries naturally. Only then, without a trace of the urine stain that Fatliquor-5.0 (pH 5.0) replenishing commences. The emulsified fat and oil encased water molecule breaks free when hydrogen bond attraction takes place between the fat and oil with the protein fiber, leaving a breathing space essential for leather transpiration to function naturally. The fat plumps the leather with fullness from easily collapsing into creases and wrinkles during stress or flex, while the oil lubricates the fibers so that they slide over one another like millions of inter-connecting hinges with smoothness. One important unique characteristic of leather is suppleness with strength and much depends on the fatliquor, in this holistic approach to effective leather urine decontamination and restoration. For severe neglected cases with finishes damages as seen in this picture, refinishing commences after leather suppleness restoration.

    Name:  rogerIcon.jpg
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    Roger Koh
    Leather, Skin, Hair, Eye & Acne Care System Formulator
    Consultant / Practitioner / Instructor / Coach
    web: www.leatherdoctor.com
    forum: www.leathercleaningrestorationforum.com
    email: [email protected]

  3. #3
    Join Date
    Jun 2021
    Posts
    2

    Default

    Roger, thank you for your reply.

    I have two questions though, firstly shipping from Canada to my location will take anywhere from 1-2 months according to your website's estimates, will this be bad for the leather? Should I continue to apply vinegar and cover in paper towel and plastic? Currently I have put a plastic liner and a cover on the sofa in the meantime.
    Here's a photo of the current appearance after repeated dabbing of white vinegar and letting rest.

    The white chalky appearance has improved significantly.


    Secondly, because of the shipping times I'd like to order enough of the Urine + Degreaser products to cover at least one of the cushions, for now. How much would I need? The sofa is about 2 meters long in total.
    Last edited by Danniel; 06-07-2021 at 07:29 PM.

  4. #4
    Join Date
    Feb 2007
    Location
    Greater Vancouver, Canada.
    Posts
    5,102

    Default

    >>> I have two questions though, firstly shipping from Canada to my location will take anywhere from 1-2 months according to your website's estimates, will this be bad for the leather? Should I continue to apply vinegar and cover in paper towel and plastic? Currently I have put a plastic liner and a cover on the sofa in the meantime. Here's a photo of the current appearance after repeated dabbing of white vinegar and letting rest.

    The vinegar will neutralize or prevent the urine from fermenting ammonia. Since the leather protein fiber is amphoteric material alkalinity will denature the leather, becomes slimy, stiff and cracks


    >>> The white chalky appearance has improved significantly.

    The chalky appearance is the fatliquor (fat and oil) leaching out (the result of this displaced fatliquor area will become stiff).


    >>>Secondly, because of the shipping times I'd like to order enough of the Urine + Degreaser products to cover at least one of the cushions, for now. How much would I need? The sofa is about 2 meters long in total.

    The dryness of the leather, the thickness will determine how much is sufficient to bring up to the tannery average 14% of fat and oil content. (One cushion will need at least 4 250ml bottles of
    Hydrator-3.3 and 2 250ml bottles of Fatliquor-5.0 to sufficiently replenish the original fatliquor).

    This is a more accurate calculation:

    Leather Approximate Quantity or Percentage of Fat-liquor:
    The quantities of fat-liquor (fat and oil) contents retained in the leather after a universal tannery fat-liquoring process may vary up from 14% to 16% depending on the leather types and their usage. This percentage drops as the fat and oil content diminish or leaches through aging, water, heat, or chemical overexposure. Leather rejuvenating or fat-liquor replenishing is base on the weight of the leather in relation to the percentage of remaining fat-liquor. A simple calculation of the percentage of fat-liquor topping up requirement would be as follows: If the weight of the leather in question is 100gm and fat-liquor (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% fat-liquor when dry as the 66.6% water contents evaporate. 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 fat-liquoring including cleaning up any excess surface remnants to have a sticky-free surface. In practice, with severe dryness, the ratio for LeatherHydrator-3.3 is 2 to 1 of LeatherFatliquor-5.0. It works out to be approximately 160gm of LeatherHydrator-3.3 plus 80gm of LeatherFatliquor-5.0 to replenish a 100gm dry leather from less than 1% back to the original tannery up from 14% to 16% fat-liquor content. In every bottle of LeatherFatliquor-5.0 by weight, content is comprised 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.

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