How to remove wrinkles from this 2002 BMW nappa leather seat?

Sent: Thursday, December 02, 2010 1:48 PM
To: [email protected]
Subject: Leather Kits

Hi Roger,

I have seen some of your posts on the forum and would like to know more about your products. I have a 2002 BMW with Nappa leather which I am looking to improve. I have already done a leatherique treatment twice, and I am quite happy with the results, but there is still more creasing than I would like, and I believe I the leather could still be a bit softer than it is now. Overall the leather is in great shape, besides the wrinkles on the bolster and the slight plastic like feel.
I have redone interiors in the past, by replacing the leather with pre stiched new leather, so if I need to apply products such as fat liquor from the unfinished side, I don't think I would have an issue. I have hog rings and hog ring pliers, so if need be I can remove the leather completely. Please let me know which kit you recommend and more info along with pricing.


Sent: Thursday, November 17, 2011 2:03 PM
To: Roger Koh
Subject: Re: Auto Kit-AP3 - Leather Doctor

Roger,

Now I know that the larger wrinkles have appeared because the leather has stretched a bit from the foam underneath being compressed. However, I am planning on removing the seat bottom and adding upholstery foam which should remove the larger folds in the leather. Also, since I will be adding foam, I will have access to the leather from the back/untreated side. Judging by the rest of the car, the leather seems to be red throughout, as even the back side of the leather is red in color, therefore I believe the leather is tanned not painted? Please advice.

http://i300.photobucket.com/albums/n...reases1of2.jpg

http://i300.photobucket.com/albums/n...reases2of2.jpg

Picture observation:

Picture #1
I believe your focus is on the seat cushion rather than the backrest.
There are 3 locations that show looseness of the leather – the right and left bolster from middle to the back; and the center section of the seat cushion. There are 2 possible reasons; one is what you mentioned about the sagging foam. The other could be due to over-stretching of the leather that caused the looseness. The sagging foam can be corrected by new replacement of high density foam, and the leather structure looseness could be corrected with dimensional shrinkage. Dimensional shrinkage is by causing the leather thickness (average 1mm) to plumps-up with moisture content mainly by fatliquoring (water encased fat and oil). This is done first by hydrating the leather structure to relax the creases and wrinkles preferably plastic cling wrapped it for an overnight dwell follows by manipulating the leather free of unnatural creases and wrinkles. This process can be repeated up to three days to get the desired result. Thereafter, the plastic wrapping is removed for natural slow drying. As the water contents evaporate, fatliquor is replenished with periodic application until fully saturated. When the milky fatliquor hydrogen-bond with the protein fibers, the encased water breaks free and evaporates, creating breathing space between the leather inter-fibrillary space. While the fats give the leather its fullness, the oils lubricates the fibrils allowing the fibrils to slide over one another smoothly – that gives the leather its softness, suppleness and strength.

Picture #2
This close-up picture show darkening creases could be just shadows or accumulated soiling that is recommended to be removed prior to removing the leather from the frame. This is done with Prep-7.7 with horsehair brush application especially to these creases and feathering out to the entire set. The Prep-7.7 can be left from 10 to 30 minutes dwell. Since this leather is aniline dyed prior to micro-pigmented coating, attentive observation has to be given to see if dyes do bleeds through the finishes. Remember to have camera ready to take such pictures if it does. To neutralize the prep alkalinity, Cleaner-3.8 which has an acidic pH of 3.8 is to be immediately follow through to remove the sticky residue – follows with Rinse-3.0 also an acid with a pH of 3.0 to rinse off any residue to a healthy squeaky clean. At this stage take a picture; take a close-up picture of areas especially the creases if it has a wet darkening effect. This darkening effect is where the leather structure can be access from the finish, if hydrating and fatliquor is to be done from the surface.

Since you mentioned it is Nappa Leather…often described as full-grain leather, typically aniline dyed, made from un-split skin and noted for softness and durability; often found in high-end leathers…so much so on leather type, but unknown on its finish type.

Is the finish, absorbent, semi-absorbent or non-absorbent?

A simple test with distilled/tap water on a folded tissue paper about a square inch placing on the leather and cover with see through cling wrapper, and leaving it for a hourly observation to see how long it takes for a darkening effect to take place – will determine its degree of permeability.

This test will determine how the dormant aniline dyestuff could be reactivated to resurface to refresh its appearance through the hydrating process, besides relaxing to eliminate the creases.

Roger Koh
[email protected]