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Thread: Nubuck: Removing Stains from Nubuck Sofa

  1. #1
    Join Date
    Jun 2007
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    19

    Default Nubuck: Removing Stains from Nubuck Sofa

    Roger,

    I have a customer who has a Nubuck sectional with a number of food stains and also that has faded from exposure to the sun. Do you know of a way to remove the stains and re-dye the sectional?

  2. #2
    Join Date
    Feb 2007
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    Greater Vancouver, Canada.
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    Default Nubuck Cleaning Method by Leather Doctor® System

    Re: Nubuck Cleaning Method by Leather Doctor® System

    A. Nubuck Identification
    1. Nubuck is described as a top-grain aniline-dyed leather from which the top hair cell layer has been removed through buffing to create a “fine suede-like” nap effect.
    2. Nubuck is also defined as aniline-dyed leather with its finished surfaced buffed to a slight nap or suede-like appearance.
    3. Nubuck is also known as a type of brushed leather similar to suede.
    4. Nubuck differs from suede in that while suede is created from the flesh (inner) side of a hide, nubuck is created using the grain (outer) side, giving it added strength
    and durability.

    B. Fashion Nubuck Identification
    1. Two-Tone Nubuck - The higher grains in lighter tone and the lower grooves in darker tone created by buffing.
    2. Embossed Nubuck – Heat and pressure embossed to impress a pattern onto the plain nubuck to create a textured design.
    3. Wax Pull-Up Nubuck – Derives color from dyes, and wax. When this leather is pulled during upholstering, the wax dissipates and becomes lighter in
    those areas.
    4. Oil Pull-Up Nubuck – Same description as Wax Pull-Up except it is infused with Effect Oil instead.

    C. Food Stains Identification by Appearance
    1. Stains identification by appearance will show whether it gives a characteristics of a spill.
    2. A spill that contains sugar will tend to be darken as it attract soil and are normally refers to as fresh stains.
    3. A spill that turns yellowish brown may be of tannin nature – tea, coffee.
    4. Oil stains usually turns dark and when aged may turns yellow due to hydrolysis and oxidation.
    5. An Albuminous, carbohydrates or one that contains sugar will turn white when scratched.

    D. Food Stains Identification by Smell
    1. Stains identification by smell is a simple task in positive stain identification.
    2. Some common odors are characteristically beer or vomit that turns rancid.

    E. Food Stains Identification by Color
    1. Stains identification by color sometimes gives a clue to the source of the stain.
    2. If the spot is red it could be blood, wine, red cola or other food dye substances.
    3. Color identification could be deceptive, a red bloodstain may turn to rusty dark drown with time.

    F. Food Stains Identification by Feel
    1. If a substance is red and sticky it may be cola, candy or other sugar colored substance.
    2. If the stain feels hard and dark it may be old blood stains.
    3. If it transfers to your fingers, it may have a grease base to it – Gravy or other greasy food spills.

    G. Food Stains Identification by Combinations of Appearances
    1. Food stains may be lying on top of the nubuck (buit-up) or absorbed into the leather texture.
    2. As Nubuck is naturally absorbent, it could also be a combination of absorbed and built-up stains.
    3. If it has been absorbed, this will be an indication that it was a liquid when it penetrates the nubuck.
    4. If the pH of the liquid is alkaline, rare in foodstuff; but even for perspiration stains it should also alert you
    that the alkalinity might have reacted with the acidic dyestuff.
    5. This may cause a yellowing discoloration or loss of color on some light pastel color possibly after spotting or cleaning.

    H. Food Stains Classification
    1. When identifying food stains always try to determine whether they are protein, tannin, oil-base or a compound make-up.
    2. Food stains are frequently a combination nature also known as compound stains.
    3. Basically there are three types of soil: solvent-soluble, water-soluble and insoluble.

    I. Food Stains Query
    1. Always ask customer to confirm your findings.

    J. pH Value of Nubuck
    1. The pH of Nubucks I measured is between 4 and 5 (Most leather is in the pH range of 3.2 to 4.5 – Leather Research Laboratory, University of Cincinnati).
    2. The pH of Tannery Process that goes into the conversion of raw hides into leather is shown as follows:
    Liming @ pH 12-13
    Deliming @ pH 5-9
    Neutralizing @ pH 4-6
    Bating @ pH 7.5-9
    Pickling @ pH 1-2
    Chrome Tanning @ pH 2-4
    Vegetable Tanning @ pH 3-5
    Oil Tanning @ pH 6.5-10
    Acid Dyestuff @ pH 3-4
    Direct Dyestuff @ pH 4-6
    Special Dyestuff @ pH 6-8.5
    Fatliquoring @ pH 4-6
    3. Therefore the inherent pH value of leather is mildly acidic averaging between 3 and 5.

    K. Leather pH balanced Spotters and Cleaners.
    1. The pH value of spotters and cleaners for leather should also be in the leather pH 3-5 range to work in harmony with its inherent leather chemistry.
    2. Specialty spotters’ pH value which is out of this range should be neutralized to within range of leather neutral of pH 3 and 5 after specific task is accomplished.

    L. Solvent and Alcohol Spotters
    1. All solvent spotters may have adverse effect on the solvent sensitive dyestuff.
    2. When applied as a spotter, it has the potential to destabilized the dyestuff and cause it to migrate to the outer ring edge of the spot forming ring marks.
    3. All solvent spotters have to be tested in a hidden area prior to spotting.
    4. The solvent spotters also cause natural oils in the leather to dry up.
    5. It is always wise to replenish the natural oils with a true tannery fatliquor – fatliquor5.0™

    M. Alkaline Spotters
    1. Alkaline spotters have the potential to destabilize the dyestuff by discoloration or streaks.
    2. It use will also destabilize and remove the natural oils that need to be re-fatliquored with fatliquor5.0™.
    3. Always test in a hidden area prior to actual spotting.

    N. Soil Levels with matching Cleaning Powers.
    1. Spotting and cleaning solutions should be chosen on the basis of soil levels and its likelihood of damage or change in the appearance or texture feel.
    2. Always start with the lower cleaning power of the cleaner or spotter and advance upwards if possible until experience enough to deploy them appropriately.
    3. The stronger the spotter or cleaners used, the more the need of rinsing to dilute them and to be extracted out of the leather.

    O. Dry Soil Removal
    1. All dry soil is to be removed with nubuckBrush2™ and other appropriate, spatulas, pricks, fine scrub pads or erasers.
    2. Dry soil removal includes all other fabric components on cushions and decks with HEPA vacuum for IAQ.

    P. The fundamental of Chemical Cleaning
    1. Soil suspension is the key to successful cleaning of nubuck.
    2. Methods must be employed to achieve soil suspension.
    3. The three fundamental of soil suspension include:
    a. Chemical Action
    b. Agitation
    c. Time
    4. All the above fundamentals must be considered if successful cleaning is to be achieved.

    Q. Chemical Action:
    1. After dry soil removal from nubuck and fabric is accomplished.
    2. Test for colorfastness on both fabric and nubuck.
    3. If test shows potential color bleed, spray on rinse3.0™ agitate and test again for improvement.
    4. Excess bleeding on the nubuck may be a good sign for color refreshing without resorting to color refinishing.
    5. Product label directions must be followed when applying spotters, preconditioning, degreasing and cleaning agents.

    Q1. Fabric Material:
    1. For fabric material, cleaner3.8™ should be lightly mist sprayed agitate accordingly and extract with dry absorbent towel follows by rinse3.0™ prior to nubuck
    cleaning.

    Q2. Spots and Stains:
    1. Spots and Stains identified should be taken care of with appropriate food stain spotting products namely: acidifier1.8™, basifier8.5™, deOdor4.4™,
    protein11.0™, blood9.9™, tarnish1.3™, tannin3.5™, superSpotter4.6™, others. (The numbers indicate the pH value of each product for easy pH value
    identification).

    Q3. Heavily Soiled Areas:
    1. Heavily soiled areas such as arm tops, seat cushions, or pillows should receive specific attention with either a preCleaner3.7™, degreaser4.1™ or
    superCleaner4.0™.

    Q4. Normal Soiling:
    1. For nubuck normal soiling, cleaner3.8™ should be evenly sprayed over the entire surface one cushion or section at a time.
    2. Remember the average thickness of nubuck is between 1.4 to 2 mm (i.e. between 19 to 27 sheets of newsprint thickness).
    3. As these cleaning agents are leather pH balanced, it is design to go deep into the thickness and bring out the penetrated soil without destabilizing the pH
    integrity of the leather.

    R. Agitation:
    1. For increase cleaning effectiveness and uniform cleaning agent distribution.
    2. The preconditioner or cleaner must be worked into heavily soiled areas using a nubuckBrush2™.
    3. Avoid excessive agitation when cleaning delicate embossed nubuck.

    S. Time:
    1. It is recommended that preconditioner, degreaser or cleaner be allowed 5 to 10 minutes of dwell time before proceeding.
    2. Dwell time provides the opportunity for cleaners to fully penetrate, lubricate and suspend stubborn soils.
    3. Exceptions may be made in cases where color testing reveals unstable dyes.
    4. In those cases soil removal must proceed immediately.
    5. Preconditioners, degreasers and cleaners should not be allowed to dry before soil extraction takes place.

    T. Soil Extraction:
    1. Soil extraction must be accomplished by extracting with a white dry clean absorbent towel, rotating it frequently as its surfaces become soil saturated.
    2. Towels must be changed as they become saturated as no more soil can be absorbed.

    To be continued...
    Attached Images Attached Images     

  3. #3
    Join Date
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    Default

    U. Rinse:
    1. Repeat soil suspension and removal procedures with rinse3.0™ as required until towel shows free of soil.

    V. Softening, Strengthening and Color-Tone Conditioning:
    1. Leather cleaning procedures may inevitably remove some natural oils depending on the degree of degreasing power of these spotters, preconditioners, degreaser
    and cleaning agent.
    2. Therefore the original natural oils need to be replenish with a true tannery fatliquor – fatliquor5.0™ to maintain the nubuck’s integrity and pliability.
    3. This fatliquor5.0™ will penetrate deep into the leather structure for softening, strengthening and helps enriching its color back from sun fading to a degree.
    4. This application is introduced while the nubuck is still damp.
    5. Natural slow drying will produce a softer feel and richer color tone.

    W. Drying Time:
    1. Drying time varies depending on the amount of moisture remaining after cleaning and prevailing temperature and humidity conditions.
    2. Nubuck should be dried using ambient conditions of temperature and humidity within the structure.
    3. Forced drying, especially using heat, is not recommended.
    4. In some cases using a mist spray of rinse3.0™ to “feather out” water spots may help avoid water marks.
    5. A hair dryer on a cool setting may be used to assist in drying localized spots evenly and help return leather to its original appearance.
    6. Providing proper ventilation and air movement is highly recommended to expedite drying.

    X. Wick-Up Soil:
    1. Pre-warn your customer that as it dries the penetrated soil will wick up to the surface worst than prior to your cleaning.
    2. This will demonstrate the power of the wicking process from deep from the leather structure.
    3. The pH chemistry that works in perfect harmony with the leather brings out all the penetrated soil no other wet nubuck system can match.

    Y. Grooming:
    1. Groom with nubuckBrush2™ of all resurfaced soil for a “finger writing effect”.
    2. Vacuum brushed off soil residues using a HEPA vacuum cleaner for “indoor air quality”.

    Z. Inspection:
    1. Check for appearance satisfaction.
    2. Any decision for a color refinishing will be decided at this stage.
    3. In most situations I have experience; the customer will be trilled enough to see the nubuck comes to life.
    4. And they know that you have not only safe the nubuck.
    5. You have also saved them to spend on unnecessary color refinishing.

    A1. Sensuous Conditioning:
    1. The final cleaning process is the application of leatherScent’S™.
    2. It’s the nubuck sensuous conditioner that imparts the classic unforgettable leather scent.
    3. It yields a silky feel to the sense of touch.
    4. It enhances the nubuck with a breathable non-stick surface for comfort and also shields the effect of daily sticky soiling.

    For a job like this my on going prices is a minimum of $1950 for a 3 + 2 + 1.
    1. An Oil or Wax Pull-Up Revival will be extra.
    2. A color refinishing will be extra too.

    I can post testimony of nubuck set that I have done for your viewing if you like.

    Your customers become your instant “Cheer Leaders”.

    Like me to talk about nubuck color refinishing as the next phase.

    Roger Koh
    IICRC#942 LCT MTC MSR
    Leather Doctor System®
    [email protected]
    Attached Images Attached Images     

  4. #4
    Join Date
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    Default Nubuck Headrest Degreasing

    “I also have another customer who has a nubuck chair that has a large body oil stain in the section where the head rests, would this be cleaned in a similar way”.


    These pictures show the degreasing process to the head rest without fatliquoring.

    Results will be better when fatliquoring is incorporated.

    Effective fatliquoring is accomplished when the leather structure is relaxed and plump up by the cleaner3.8™ during the degreasing process with degreaser4.1™.

    Rinse3.0™ acidifies the leather fibrils further for better fatliquor bonding fixation to the protein fibils.

    As the excess water evaporates during drying it will wick out non bonding stuffing oil and grease.

    It will also enrich the color tone of sun faded nubuck.

    All these products are water base with the numbers represent the pH value working in harmony with the leather, otherwise it is quite impossible to wet clean them safely.

    Roger Koh
    IICRC#942 LCT MTC MSR
    Leather Doctor System®
    [email protected]
    Attached Images Attached Images      

  5. #5
    Join Date
    Jun 2007
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    19

    Default

    Roger,

    i would really like it if you would explain how you re-color Nubuck.

  6. #6
    Join Date
    Jun 2007
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    19

    Default

    Roger,

    Also, is it possible to change the color of Nubuck? For instance from a tan to a dark brown?

  7. #7
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    Jun 2007
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    Default

    Roger,

    Are you able to remove all the stains or are there some that because they have set for an extended period of time, say a few months or a year, that you are unable to remove?

    Also, how much time does it take to do the complete cleaning process, one day, two?

  8. #8
    Join Date
    Feb 2007
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    Greater Vancouver, Canada.
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    Default Re: Re-Dyeing & Re-Coloring Nubuck

    Dear Pioneer,

    All grease stains have to go from the inside out no matter how long it’s been there.

    Those greasy dark headrest stains is a common sight on Nubuck.

    Nubuck is highly absorbent, so those greasy stains may have soak through the whole thickness equivalent to between 19 and 27 sheets of normal newsprint.

    Combination of deGreaser4.1™, superCleaner4.0™, cleaner3.8™ and rinse3.0™ will eventually draw out these grease and oil through the wicking process.

    These oil and grease are accumulation through the years usually 3, 5 to 7 years that I have worked on.

    It may take 3, 5 to 7 wicking process or double the times (it depends – no magic all logic with hard work).

    Eventually they will be out with satisfaction.

    The pH of these cleaner works in harmony without destabilizing the leather chemistry integrity.

    There is no cleaning risk; however what ever oxidation taken place through time may have cause a discoloration yet to be revealed when all the grease is removed.

    It is usually the alkaline residue of cleaners that cause discoloration problem.

    If no previous attempt have been made, through my experience they will turn out good with the final process with fatliquor5.0™.

    Fatliquor5.0™ can be diluted up to 10 parts with distilled water if spray on dry surface to adjust the color-tone.

    If it is to be Re-Dye/Re-Color, fatliquor5.0™ is preferably to apply after the Re-Dyeing/Re-Coloring process.

    It is never wise to do a refinishing for the purpose of a cover up those greasy stains.

    Nubuck has to be absolutely clean from inside out before you can attempt a refinishing.

    Nubuck Re-Dyeing / Re-Coloring

    anilineDye™ provides a transparent natural or unfinished look.

    nubuckColor™ provides better coverage with opacity.

    To refinish the same color or one tone deeper I prefer to use nubuckColor™.

    If it is to change color from tan to dark brown I will use the anilineDye™ for penetrating deep into the leather.

    Then follows with the second or third application with nubuckColor™.

    colorFix™ is to set the dyes and fix the micro-color.

    The anilineDye™ advantages is really a deep re-dyeing all the way to the roots (so to say).

    The disadvantages is that it is not as colorfast as the nubuckColor™ and may bleed with solvent spotter resulting in rings.

    The nubuckColor™ has covering power and more colorfast than anilineDye™ but loose out in super fine feel.

    It has no bleeding problem and with a good colorFix™ crocking will be greatly reduced.

    Application Technique

    Set your air pressure at 80 to 100psi.

    I use either a DevilBiss JGA-700 or a Paarche H70089 depending on the surface area.

    Test cone shape spray pattern to increase atomization and decrease feed to produce a dry application.

    Rotate dry application in a circular motion with continuous brushing deep into the nap without over flooding in between naps.

    Repeat all spray application in this manner a section at a time using either a nubuckBrush2™ or suedeBrush3™ accordingly.

    Grooming

    When dry brush and groom for a “finger writing effect”.

    Fatliquoring

    An even application with fatliquor5.0™ will soften, strengthen and enrich color further.

    Sensuous Conditioning

    Finished by spraying leatherScent’S™ for a silky feel, non-stick surface with the unforgettable classic leather scent.

    See attached pictures.

    Any further questions are welcome.

    Roger Koh
    IICRC#942 LCT MTC MSR
    Leather Doctor System®
    [email protected]
    Attached Images Attached Images     

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