Leather care thoughts...

[TOGWT]

There are some interesting posts on leather care over on DW, I am trying to evaluate them. The 'expert' is stating that (a) conditioners will not permeate the urathene covering (b) it is not necessary to condition leather with oils as the tanning oils are sealed into chrome tanned leather, the only requirement for this type of leather is moisture.

To be continued

[dnegri]

Does anyone recommend using 303 protectant on leather? I just bought a bottle of it and tried it already but I noticed that when I opened my car door while it was raining a few days after applying it left run marks on my trim.....is that common?

[TOGWT]

Ultra violet radiation dries the moisture from leather / covered leather and will cause both materials to crack and / or shrink causing seam stitching to break

303 Space Protectant should be applied lightly to surfaces, allowed to dry and then buffed with a micro fibre towel

[Dogged]

Originally Posted by TOGWT

There are some interesting posts on leather care over on DW, I am trying to evaluate them. The 'expert' is stating that (a) conditioners will not permeate the urathene covering (b) it is not necessary to condition leather with oils as the tanning oils are sealed into chrome tanned leather, the only requirement for this type of leather is moisture.

To be continued

I just read through the thread on DW you referenced. It does raise some interesting questions, particularly:

1. Do leathers used in automobile upholstery lose oils and fats over time that need to be replaced with a leather conditioner?

2. Is leather upholstery used in automobiles absorbent or non-absorbent? In other words, does a leather conditioner soak into the leather or just coat the surface and never come into contact with the leather? If the leather is absorbant, does a conditioner do more harm than good? If the leather is not absorbant, does the conditioner do anything other than act as a protectant, and can a conditioner actually do some harm by breaking down the surface coating on the leather?

3. Should a leather conditioner be used, or just a leather protectant that contains a UV blocker and possibly repels moisture?

If you reach any conclusions, I would be very interested in your thoughts.

[TOGWT]

After reading the posts on DW and some discussions with some leather distributors / hide tanning companies these are my conclusions, which I should add are a major re-think on my leather cleaning / care recommendations


1. Do leathers used in automobile upholstery lose oils and fats over time that needs to be replaced with a leather conditioner?

A1. First we must differentiate between chrome tanned covered leather and natural leather hides

2. Is leather upholstery used in automobiles absorbent or non-absorbent? In other words, does a leather conditioner soak into the leather or just coat the surface and never come into contact with the leather?
A2. A natural leather hide is absorbent and occasionally oils should be re-introduced to avoid the hide drying out

3. If the leather is absorbent, does a conditioner do more harm than good?
A3. See above. I think a conditioner if used sparingly will help to preserve the leather hide

4. If the leather is not absorbent, does the conditioner do anything other than act as a protectant, and can a conditioner actually do some harm by breaking down the surface coating on the leather?
A4. Some oils (particularly solvent-based silicone) will have an adverse effect on polyurethane by breaking down the polymers and causing the covering to shred

5. Should a leather conditioner be used, or just a leather protectant that contains a UV blocker and possibly repels moisture?
A5. An ultra violet (UV) protection should be used with either type of leather

[TOGWT]

Leather:
Many people are unaware of the fact that since the late ‘80s early ‘90s newer domestic cars do not use natural leather hides anymore. Approximately 80% of vehicle manufacturers have used covered leather for their interior upholstery. It’s made from natural hides, chrome tanned and uniquely treated with a light pigmented urethane paint coating or a vinyl covering to make it more viable for automotive seating. It retains the softness of natural top-grain leather but resists fading in direct sunlight, which besides body oil is leathers worst enemy. This type of automotive upholstery finish should really not be considered as leather hide but treated as a vinyl.

Spills wipe off with a moistened cloth, the urethane resin or the vinyl covering require a limited amount of oil to stop it from drying out (just like a paint system's clear coat) coated leather is permeable and the urethane requires replacement of its moisture, heat will allow it to penetrate.

Identifying characteristics- covered leather has a uniform colour and grain patterns; will not scratch easily; water drops will not change its colour.

Cleaning- it is very difficult to remove the ‘natural’ oils from leather especially using detergent cleaners so replacing them is totally unnecessary and possibly detrimental to any leather hides. Modern chrome tanned upholstery leather is a very sophisticated product and the notion that it is something straight from nature that has to be fed and nourished is totally incorrect, the oils and fats in C/T leather are introduced after the processes have reduced the skin to pure collagen fibre. The fat liquoring process carefully introduces fats/oils of a specific type back into the leather to coat the fibres; these are balanced to produce the desired end product and are very stable and very difficult to remove. Trying to add more fat/oil etc is totally unnecessary and is of no benefit. On an absorbent leather products used for ‘conditioning’ and ‘feeding’ will soak into the leather upsetting the balance and over time change it to the detriment of the leather. If the leather is covered with a polyethylene coating, and therefore non-absorbent, then these products have no where to go so will sit on the surface, getting slightly sticky and attracting more dirt.

Cleaning Methodology-
1.Use a soft horse hair brush (Groit's Leather & Interior Brush) to remove any dust or grit from the seams and vacuum the seating areas dust
2.Apply a cleaning solution (Water /Woolite® or Dreft® 6:1 ratio or higher) on to an applicator pad (this Mesh towel is double woven micro fibre, made to be safe and scratch-free for all leather and vinyl finishes - poorboysworld.com
3.Apply to one area at a time (i.e. a seat back). To remove stubborn dirt or grime gently agitate the surface with a boar's hair cleaning brush (this will not harm the leather) then use a clean, damp Micro fibre towel to rinse.
4.To bring back a matte finish and safely remove prior use products, use a solution of distilled water and a mild liquid soap (Woolite® or Dreft® 4:1 ratio or stronger) on to an applicator pad
5.It may be necessary to repeat the cleaning process to get it back to a matte finish.

Note:
a) Most leather cleaners also contain oils (for lubrication) over use will make the leather surface 'shine' as the oils cannot permeate the polyurethane covering

b) Leather that has become cracked from inadequate or inappropriate care usually cannot be restored to its original state by most available products / methods

Maintenance cleaning- use a mild liquid soap cleaning solution (Water /Woolite® or Dreft® 10:1 ratio) on to an applicator pad and apply to one area at a time

© 2004 – 2007 all rights reserved - Jon Miller aka TOGWT™

[Dogged]

This is an excerpt from an article published by The Leather Training and Technical Dept. Ltd. (LTTD) discussed in the DW thread:

“As a general rule and particularly with pigment coated leathers you will only be cleaning the surface or finish so your cleaning process will never come into contact with the actual leather . . .

. . . .

It is incredibly difficult to remove the ‘natural’ oils from leather especially using detergent cleaners so replacing them is totally unnecessary and possibly detrimental on both finished and unfinished leathers. Modern C/T (Chrome Tanned) upholstery leather is a very sophisticated product and has been for decades. . . . Trying to add more fat/oil etc is totally unnecessary and is of no benefit. On an absorbent leather products used for ‘conditioning’ and ‘feeding’ will soak into the leather upsetting the balance and over time change it to the detriment of the leather. If the leather is non absorbent then these products have no where to go so will sit on the surface, getting slightly sticky and attracting more dirt. If they do manage to ‘get in through the cracks’ the results will be the same as absorbent leathers with the added problem of adversely affecting the bond between surface coatings and the leather. . . .”

pH and Leather Cleaning - Cleaning Chemicals, Machines and Equipment | World of Clean


I think the message from the article is the key to maintaining C/T upholtery leather is cleaning the leather, but a conditioner designed to be absorbed into the leather either is unnecessary or in some cases counterproductive. Use of a protectant with a UV blocker and perhaps stain resistant feature is consistent with the advice given in the article.

Since there are so many leather conditioners on the market advertised as penetrating and perserving leather, and restoring oils dissapated from the leather over time, the article challenges fundamental leather conditioner manufacturer claims for many products.

The article makes me pause regarding whether to apply a leather conditioner, or just to apply a protectant after cleaning the leather such as the 303 protectant.

[Dogged]

Originally Posted by TOGWT

A2. A natural leather hide is absorbent and occasionally oils should be re-introduced to avoid the hide drying out.

How can I determine with the leather in my car is chrome tanned or natural? I take it that you disagree with LTTD's comment that "replacing ['natural' oils] is totally unnecessary and possibly detrimental on both finished and unfinished leathers."

[Holden_Caulfield04]

This advice seems to run counter to the entire detailing industry. I've heard claims from many well known manufacturers that are completely untrue as well, so take every piece of advice with a grain of salt.

Here's two examples:

1) Einszett

"Like all waxes, If you attempted to apply multiple coatings, you would only be successful in removing some of the coating applied prior. There is absolutely no benefit to applying multiple layers of wax including improved depth and shine and longevity. The only success achieved is using more product than is necessary and more importantly, more time than is necessary. Less is more. For this reason, professional detailers do not 'layer'."

2) Meguiars

At an Open Garage Session, the Meguiars representative suggests that you cannot completely remove Orange Peel from a factory clear coat. He suggests that if you do so, you will induce clear coat failure in 6-12 months.

[Dogged]

Those are a couple of pretty funny examples. It sure seems counter-intuitive to state that a leather conditioner cannot help restore the dissipation of oils from a natural leather. I am sure we have all seen old dried out leather.

[TOGWT]

1) Einszett

"Like all waxes, if you attempted to apply multiple coatings, you would only be successful in removing some of the coating applied prior. There is absolutely no benefit to applying multiple layers of wax including improved depth and shine and longevity. The only success achieved is using more product than is necessary and more importantly, more time than is necessary. Less is more. For this reason, professional detailers do not 'layer'."

A1. See my comments on both ‘Spit Shining’ and Layering Waxes’ The statement ‘professionals detailer’s do not layer’ has a lot of truth to it, they are paid for results and as long as the vehicle is ‘clean and shiny’ they have no need to take the finish any further. Both spit shining and the layering of waxes are techniques used by enthusiast and Concours d’élégance entrants

2) Meguiars

At an Open Garage Session, the Meguiars representative suggests that you cannot completely remove Orange Peel from a factory clear coat. He suggests that if you do so, you will induce clear coat failure in 6-12 months.

A2. Mostly true- it is possible to wet-sand orange peel, but if you try to eliminate it completely you risk severely compromising the paint thickness (but this is immediate, not within 6-12 months.

Footnote: A paint film surface is a delicate thin coating; easily dulled and very easily scratched and / or damaged. Choose carefully the advice you listen to and more importantly what advice you act upon..