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Thread: De Sede Sofa restoration

  1. #1
    Join Date
    Jul 2017
    Location
    Los Angeles
    Posts
    1

    Default De Sede Sofa restoration

    Hello, I recently acquired a DS-42 sofa (photos below). I believe it to be made from bull neck leather. It's quite thick aniline leather with natural color. While I don't mind some patina, the original flat light tan color of these is lovely.

    There are a few things that I'm interested in doing the following:
    1. To whatever extent is possible, lighten what appear to be grease or body oil stains. Trying go achieve the original light tan (currently visible on sides & back).
    2. Remove what smells like old cigarette odors.
    3. Remove the shiny, waxy texture on the seating surfaces, and protect. Again, the sides and back have a very supple, flat/matte finish.

    Thanks

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  2. #2
    Join Date
    Feb 2007
    Location
    Greater Vancouver, Canada
    Posts
    4,396

    Default

    >>> 1. To whatever extent is possible, lighten what appears to be grease or body oil stains. Trying to achieve the original light tan (currently visible on sides & back).

    Body oil and grease that penetrates the leather directs contribute to the soiling. Browning comes from the sweat that contains traces of urea and ammonia that denatures the leather. The contaminated areas are tested with a wet hand to detect any tackiness or sliminess. Stiffness and cracking of the leather to contaminated areas is the cause of fermenting sweat that weakens the ionic positive (+ve) charges of the leather protein leather, causing the tanning agents to break its hydrogen-bond. Test with a white cloth to inspect for fugitive dyes is also an indication of denaturing leather that weakens its pH chemistry integrity. A healthy leather should have an average pH value of 3 - 5 and vegetable-tanned leathers is lower then chrome-tanned leathers. That is why we see more crackings in vegetable-tanned leathers then chrome-tanned leathers. Vegetable-tanned leather is more “fatliquor” thirsty. Fatliquor is the life-blood of leathers and the sweat contamination diminishes it. To avoid leather stiffness or cracking the degreasing process and the rejuvenating process is recommended as a continuous ‘wet’ process in this sequence. Degreaser-2.2 > Acidifier-2.0 > Hydrator-3.3 > Fatliquor-5.0. The leather is only allows to be fully dry after Fatliquor-5.0. And slow drying will produce a suppler leather as well. Vechetta-2.8 is used to lighten any browning through redox (reduction-oxidation) treatment when the leather is perfectly dry.


    >>> 2. Remove what smells like old cigarette odors.

    The cigarette smell is oil based with a very small micro and have lodge into the micro pores of the leather surface.
    It is removed by Prep-4.4 in combination with CleanSmoke-4.7.

    >>> 3. Remove the shiny, waxy texture on the seating surfaces, and protect. Again, the sides and back have a very supple, flat/matte finish.

    The entire surface will need to be wet out to avoid rings or lines. The above Prep-4.4 and Degreaser-2.2 system most probably will remove the shiny, waxy texture all together. To keep it as it is Protector-D/D+ is recommended.

    Good to find out from the manufacturer if this is a vegetable-tanned leathers.

    More readings . . .

    Vegetable-tanned leather is tanned using tannin and other ingredients found in vegetable matter, such as tree bark prepared in bark mills, and other similar sources. It is supple and brown in color, with the exact shade depending on the mix of chemicals and the color of the skin. It is the only form of leather suitable for use in leather carving or stamping. Vegetable-tanned leather is not stable in water; it tends to discolor, so if left to soak and then dry it will shrink and become less supple, harder and easily crack. In hot water, it will shrink drastically and partly gelatinize, becoming rigid and eventually brittle and crack.
    Unlike other tanning type, vegetable-tanned leathers will require more fatliquor to keep it supple from easily cracking. In extreme dry leather condition with fat and oil moisture level below 7%, it is recommended that leather rejuvenation commence immediately after cleaning or stain removal before the leather becomes dry again.
    Leather without hydrating to relax the leather fibrils and fatliquor replenished prior to drying will leads of stiff leather and subject to easily cracking.
    A leather moisture meter or an equivalent common wood moisture meter will be useful to take the reading of its fatliquor level. A healthy leather fat and oil moisture level would read about 15%.

    Leather Problem Solving Matrix / Guide / Instruction

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    See Kit-V5.dr for body oil, grease and sweat,and Kit-V5.so for cigarette smells.
    http://www.leatherdoctor.com/vegetable-tanned/


    Roger Koh
    Leather Care System Formulator
    Consultant / Practitioner / Instructor
    web: www.leatherdoctor.com
    forum: www.leathercleaningrestorationforum.com
    email: roger@leatherdoctor.com

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