The top grain finish was begining to deteriorate when I was erasing the dark contamination after it had dried, so we stopped.
This is the working of the sweat shifting alkaline that denatured the leather.
then proceeded to clean from the back side Degrease 2.2 + rinse several times, the back started to fall apart also
This is the result of prolong alkaline hydrolysis of the stain; same as above.
Is there is missing process of leather rejuvenating to replenished the fatliquor (Hydrator-3.3 > Fatliquor-5.0); leached out by the alkaline contamination; before proceeding to the repair?
We then patched it from behind, I used linen cloth (the only thing we had large enough to reinforce the entire area.
What was used for bonding the linen and the suede side (recommended to used Bond-3D with a suede to suede bond instead for a lasting bond, as this owner will continue to use the leather habitually; that may lead to repeated problem; causing premature delaminating between the cellulose linen and the protein fiber)?
Then filled the bad areas on the front with stucco and used impregnator to try and strengthen the entire area. I then dyed with semi color and top coated. The final result good.
Hope the look is good to stand out the stress of usage; only time will tell; I would prefer to repair this area with Bond-3D filling up with suede fibers for added strength in flexibility without the fear for premature cracking.
Is there a way in the future to strengthen an oily greasy spot prior to cleaning,
By acidifying, hydrating and fatliquoring; this three in one process neutralized, cationize the protein fiber more positive (+) to restore and strengthen the hydrogen-bond between the leather protein fibers with the leather constituents especially fatliquor (lifeblood of leather). The other advance technique is by “re-tanning” it first prior to fatliquoring. This chemistry of re-strengthening the leather is more homogenous than using mediocre scaffoldings of the leather with patches.
It seems the oil/ grease are hiding the damage and actually holding the leather structure together until we attempt to clean it exposing the damage to the leather structure. I've had this happen several times and it looks like we don't know what we're doing when the leather starts falling apart.
For future encounter…remove the excess oil, grease and sweat build up gently with Degreaser-2.2 > Rinse-3.0…Rejuvenate the leather structure with Hydrator-3.3 > Fatliquor-5.0 overnight…thereafter continue with deeper degreasing of the contamination…then follows with sufficient Fatliquor-5.0 again.
Tips:
For absorbent aniline leathers use Impregnator-26 with judgment; as the strengthen area may feel different from the surrounding areas.
Using absorb-a-stain, depends on its micron size may clog up the fine leather pores unnecessary and may cause poor adhesion, as coating products requires these sites for good anchorage.
Roger Koh
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