Restoring darkened bike saddle

[alphamoose]

Hi, I've got a bike saddle made with vegetable tanned leather that has gotten really dark and discolored. I've attached a photo showing it. Only the section at the very back and at the very front have the original color. Is there a way to restore that?

[Roger Koh]

>>> vegetable tanned leather that has gotten really dark and discolored.

These are the contributing factors that gotten the vegetable-tanned leather really dark and discolored.

1- Body oil and grease
Body oil and grease when penetrates the leather it saturate it and darkens (leather stuffing oils and conditioners will also darkens the leather).

2- Sweat
Sweat that ages shift from almost neutral pH to alkaline pH (so does any solution that has a pH value more then 7) will exaggerate the discoloration. When pH value moves higher, the vegetable-tanning agents breaks the hydrogen bonding and migrates with a darkening effect.


>>> Is there a way to restore that?

A- Body oil and grease are removed by emulsification with Degreaser-2.2 > Acidifier-2.0 > Hydrator-3.3 system.

B- The migrating tanning agents darkening effect is rectify by redox (reduction-oxidation) reaction with Vachetta-2.8.

Caution:

Cracks preventing is the utmost concern when comes to cleaning aging vegetable-tanned leathers.

1- The leather must not be put to dry without replenishing the leather with Fatliquor-5.0 sufficiently (average 14% when dry with fat and oil). Fatliquor-5.0 is a ionic negative (-ve) charged oils that hydrogen bond with the leather protein fibers, unlike stuffing oils that clogs up the breathing pores and manifesting as darkening effects.

A holistic approach with supporting system
Leather Doctor Kit-V4 - Vachetta Leather Darkening Removal Kit
is recommended for further readings from:

http://www.leatherdoctor.com/kit-v4-...g-removal-kit/





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

[alphamoose]

A bit confused by the instructions. Steps A, B, and C on those instructions seem to be alternatives to each other? It's not clear to me what applies in this case. thanks.

[Roger Koh]

>>>It's not clear to me what applies in this case.

This is a more straight forward instructions without the science behind the working.

Step-1 Cleaning Process:
VachettaPro-1.2 is applied to the entire surface and work with Eraser-4 and Brush-1 follows with Cotton Terry Towel extraction. It is repeated with interval (allowing the penetrated soiling to come to the surface) and extract until the towel shows clean again.

Step-2 Degreasing Process:
Degreaser-2.2 is applied to the greasy or darkens areas and work with Eraser-4 and Brush-1 follows with Cotton Terry Towel extraction. It is repeated with interval (allowing the penetrated soiling to come to the surface) and extract until the towel shows clean again.

Step-3 Rinsing Process:
Acidifier-2.0 is applied to the entire surface and work with Eraser-4 and Brush-1 follows with Cotton Terry Towel extraction. It is repeated with interval (allowing the penetrated soiling to come to the surface) and extract until the towel shows clean again.

Note:
This above 3 steps is the relevant “wet cleaning process” that applies in this case; unless another known category of stain that require removal by “emulsification process” as well.

Tips:
Logically, cleaning and rinsing products have to reach below the stains deep into the leather structure to cause the movement of the soiling to move upwards for towel extraction, especially during the rinsing process.

Observation:
The leather should show an improvement in appearance, it depends on the thoroughness of the above 3 steps process. As any liquid might still brings up residual soiling to the surface. Working with the Eraser-4 helps to erased soiling from the surface as well besides just towel extraction and brushing with Brush-1.

Caution:
Do not allow the leather to dry below 25% total moisture level (if you have a moisture meter) from magnifying the existing cracklings prior to Fatliquor-5.0.

Step-4 Hydrating Process:
Hydrator-3.3 is applied and brush-in with Brush-1 to saturate the leather structure to relax it. It is hydrated until a little moisture ooze out when press with fingers. The surface is brush, erase and cotton terry towel extract until towel shows clean. As each flooding of the leather structure would bring up some soiling as well. When leather is towel extracted until about 25% total moisture level, Fatliquoring process begins.

Step-5 Fatliquoring Process:
Fatliquor-5.0 is applied with the help of foamBrush-3, either direct to the surface or into the foamBrush-3 prior to application to avoid over spraying. Fatliquor-5.0 is meant for the leather structure to supple it when dry. It replenished the lost of existing fatliquor to the original average percentage of 14% of ionic negative (-ve) charged fat and oil. 5/6 of the water content will evaporate, leaving only 1/6 part of fat and oil. Thus application is repeated a few times to surface saturation, absorption while the water contents evaporates naturally. When milky surface disappear, the surface may be continue to be erased, brushed and towel extracted of further soiling residue brought up by the release water content, at drying intervals. Any sticky residue that remains on the surface is removed with Hydrator-3.3 and test for satisfaction. In cold weather, the fatliquor may be warm-up to room temperature prior to application. Allow slow drying for extra suppleness. The final inspection is after Eraser-4.

Step-6 Inspection:
At this stage, all embedded soiling should be removed; otherwise the entire above 6 steps may be repeated. With satisfaction Darkening effect remains is most probably the migrating vegetable-tanning agent that is only rectifiable through a redox (reduction-oxidation) reaction with Vechetta-2.8 on a dry surface.

Step-7 Redox (-reduction +oxidation) Reaction:
Vachetta-2.8 is applied onto the dry surface and Brush-1 to saturate the depth of the surface generously and let to natural dry for redox reaction to take place. Residues are erased with Eraser-4. Hydrator-3.3 may be used to remove residue within crevices and creases with Brush-1 more efficiently as well. When dry the surface is again erased and brush to satisfaction prior to Protector-D.

Step-8 Non-stick, Rub-resistant Protection:
Protector-D is applied brush-in and let dry, and the seat is ready for use.

Questions for clarification is welcome.


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

[Leather Exotica]

By watching at the condition of your bike saddle, i would like to recommend that you should prefer an expert at leather care rather than taking charge of this on your own.