Various Leather Surface Conditions and Correction

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How your leather feels (its Patina – literally ‘hand’) tells you more about its condition than anything; it should feel like something between velvet and satin. Supple, inviting and luxurious. Leather care starts with maintaining factory fresh feeling leather from the beginning. Keeping it clean is important, and hydration is the key; preserving the life, flexibility, appearance and longevity of your leather.



An often heard comment “If it good enough for the leather upholstery in a Ferrari it must be good enough for mine�; problem with this statement is that they are very different finished leathers. The most fundamental question to be answered before you clean or care for leather or any other material is to establish the type of finish used on the vehicles upholstery as the cleaning and care methodologies are very specific for each type



1. Pigmentation (Colour) Replacement - Certain areas of your vehicles leather interior like seats, upholstery, side mouldings and steering wheels inevitably start to show signs of wear, even if well taken care of, that spoil its overall impression. Often these imperfections are not serious and are simply colour that has worn off or light scratches in the leather surface which can be removed and will disappear with the right application technique and leather pigmentation. Swisswax Leather Refurbishing Pigmentation



2. Dry leather - it is the moisture level that has altered and re-hydration is needed to restore balance. Keeping leather clean and hydrated is the key to maintaining leather and although commercial `conditioners` may `feel good it`s not the leather itself that feels softer, but merely the product sitting on the surface.(See also Moisture Content)



3. Stiff leather surface – Leather Master Soft Touch (ex Vital) will soften leather that has become dried out, stiff or is squeaking. It is also excellent for improving the tactile feel of leathers.



4. Deformed leather surface – leather upholstery fibre structure will stretch in all directions with no particular grain or stress pattern. The urethane surface coating will not withstand multi directional stress, however, and when it’s flexed or stretched continuously in the same place the surface coating develops an indentation, car seats will often leave a ‘dent’ in the upholstery surface, however it is the foam that is deformed, more than the seats covering. The application of low pressure / dry vapour steam will help restore the shape, used in conjunction with hand pressure. Steaming is what the factory does to mould the leather around all the curves of seats and interior panels, and upholsters use to stretch or reshape leather.



Place a damp micro fibre towel in the microwave and heat for a few minutes - until they are really hot but not so hot that you can`t touch them. Place on the seats and leave for a few minutes - great at removing ingrained dirt too.



5. Delaminating –occurs when the pigmented urethane protection separates from the leather substrate. If oil is allowed to permeate any micro fissures in the leather or via the stitching it will compromise the resin binder system and delaminate from the hide releasing its adhesive bond, and it will be able to move in a different direction from the hide, which will result in surface fissures and cracking, further compounding the problem eventually leading to the subsequent replacement of the protective covering



6. Creasing - automotive finished leather is a multi-strata material, it comprises; a water-based urethane pigmentation (colour) to provide both an even colour and protection from wear when getting in and out of the vehicle and a thin water-based urethane (Ethyl carbamate) used for protecting automobile upholstery.



Similar to a paints clear coat, is classified as a semi-solid permeable membrane, being a thermosetting polymer (elastomers) it remains flexible while retaining its tensile strength, to enable it to expand and contract, following the temperature fluctuations (elasticity) of the substrate and is therefore subject to show creasing.



If dirt and / or abrasive grit are allowed to remain in these creases it will abrade the surface, eventually causing the leather to split along the crease lines, dirt in these crease lines also makes the surface appearance appear worse than it is, especially on light coloured finished leather. So keeping the finished leather surface clean is very important. If the finished leather creases have become excessive the pigmentation and / or the urethane can be renovated.



7. Cracking – keeping leather clean is the key to finished leathers durability, it is the combination of dirt and abrasion that causes the finish to crack and deteriorate over time. It is the pigment/finish coating that cracks and not the leather itself so keeping the leather clean will help prevent dirt from causing a problem.

Urethane upholstery fibre structure will stretch in all directions with no particular grain or stress pattern. The urethane surface coating will not withstand multi directional stress, however, and when it’s flexed or stretched continuously in the same place the surface coating develops minute cracks. Repeated flexing and stretching eventually causes what appears to be a ‘cracks’ in the surface coating, but is usually the pigmentation taking on wear pattern or directional creasing



Leather Repair Compound (DT-152 Leather Magic) this is a water base filler material which is air dried requiring no heat to cure. When cured, this material remains totally flexible and natural feeling just like the original leather. It is a thick, paste compound which may be easily worked into crevices and cracks in order to bond the separated leather together permanently and fill crevices completely flush with the surrounding surface areas.



Cracked and / or faded surfaces need to be correctly prepped and then re-dyed. By using an aqueous (water-based) pigmentation product like this kit from Leather Magic; wipe the leather down with the solution, using the 220 grit sand paper; this will remove most of the minor creases and provide a `key` for the pigmentation. Apply 3-4 thin coats of colour (allow to dry between coats) you have the option to spray the final coat with a sprayer (all included in kit) – Leather Magic Repair. And then add a clear topcoat for surface abrasion protection



8. Loose covers- the urethane pigmentation upholstery fibre structure of finished leather is designed to stretch along with its substrate, however sometimes it becomes over-stretched and in some instances can be rectified by dampening the surface and then applying heat it’s possible that the surface will tighten up.. Dampen the surface (do not soak) with distilled water and then position the end of a hair dryer eight to 10 inches away from the wrinkled leather surface. Move the end back and forth so that the hot air is not concentrated on one section of the leather for too long. This prevents the dryer from burning the leather.



The heat from the hot air in the dryer will gradually shrink the leather, tightening its surface (this is the way leather is fitted in upholstery shops, i.e. shrink to fit) and effectively removing the wrinkles. Hair dryers operate at a lower temperature than professional heat guns that are typically used to shrink fit leather. As a result, it might be several minutes before the wrinkles are completely gone.

Loose covers could be caused by foam padding compression, which will require replacement. Also be cognizant that if oils have permeated between the hide and the pigmentation coating it may have become delaminated, which means the two surfaces are moving independently



9. Bolster abrasions - it will depend on how badly the leather is abraded. Most bolsters have sections where the leather is more worn than others. If it is heavily worn, the leather can be very thin. You can tell by pinching the leather to see if it is paper thin. Too much sanding will result in burning through the leather. Lightly sand the finish and then apply a filler



10. Scratched leather – Leather Master Scratch Away (A-Aniline / Non-Coated) is a professional formula designed to erase these light surface scratches and scuffs. It performs this by moving the surrounding dye to cover the area where the colour is missing – Detailer`s Domain



11. Scuffed (Covered) leather - use a hair drier (not a heat gun) at a 300 angle to heat the area while massaging it, this will lift the scuff out. Then apply LM Leather Protection. If it is still noticeable then see - 1. Pigmentation (Colour) Replacement .



12. Urethane surface scratches - for light slightly scuffed urethane covered upholstery; using a 2000 grit finishing paper, with light pressure sand the area until the marks have faded. Then use a very thin application of Leather Master’s Leather Filler, water- based acrylic paste that fills out scratches in leather or any part of that grain that is missing.



13. Urethane covered hides - the oils secreted from your skin are slightly acidic and may compromise the urethane covering. Removing these oils is paramount to leather care, but limiting the amount of bare skin you expose to your seats and interior is a great way to prevent discoloration. Once damage to the extent of cracking is apparent on urethane covered upholstery, there is no way to restore them to original factory condition without re-finishing them.



14. 1z Plastic Cleaner (Plastik-Reiniger) was originally developed to protect vinyl tops from oxidation and embedded dirt build-up. Clear-Cote is also a protective coating for newly refinished leather or vinyl. It provides a durable, washable surface for any leather or vinyl upholstery; available in original gloss or matte finish. Use a fast-drying lacquer thinner to remove the old colour coating. Apply colour, allow drying thoroughly and then applying Color-Plus



15. Squeaky leather – see Leather Master Soft Touch



16. Burns or torn leather – scrape away any burned edges and cut off any rough /frayed particles. Install a sub-patch under the leather (wait until he adhesive is tacky before placing the patch) and if necessary use a filler to level the surface. Use several light coats of filler dried between coats. You can use a hair dryer to assist in drying. Remember to hold hair dry at a 300 angle. After the leather repair is level, apply a colour dye to match



17. Holes or Slits like tears - can be repaired by cleaning any rough or frayed edges and then placing a sub-patch of backing material that is larger than the hole must then be secured in place by means of a sub-patch and adhesive to give the leather patch something to anchor to. Before you insert the backing piece cover it with adhesive, allow the adhesive to become tacky.

Take a piece of circular leather cut to a half inch larger all round than hole and hold it in place with a flexible adhesive applied to the sub-patch backing piece. Pro Stick 65â„¢ Hi-Strength- spray adhesive for bonding foams, carpet and upholstery



18. Damaged or Torn Stitching - an oil-based product will attract abrasive dirt and permeated the leather via the stitching, the oil will soften the leather, and the abrasive dirt plus friction will caused the leather and stitches to tear. To stitch leather properly, you need specialist tools, its s not like stitching fabric as the leather is thick and resists piercing. There are a host of problems unique to stitching leather, and there is an array of specialized tools just for this process. The needles tend to be much larger than needles that are meant for sewing cloth, these have triangular points which cut through the leather. Waxed polyurethane, linen or canvas thread is usually used for stitching. The use of an awls and a pinwheel requires that the leather to be resting against a firm surface, usually a small wooden block, so you need to remove the hide from the foam underneath to re-stitch leather.



19. Leather pigment restoration – kits are available that allows you to recolor worn and faded leather easily. The colour coat provided is a water- based material, colour matched, that is designed to be highly compatible with leather, and provides a long lasting finish



20. Sticky leather surface - body oils (or sun-tan oil) mixed with road dirt from the a/c could be the cause or an oil-based product as used; use Leather Master Leather Degreaser (check for colour fastness) this aerosol product is ideal for cleaning oily stains; it dissolves and removes oil and grease from leather surface. This cleaner can be applied for cleaning all types of leather.

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[C. Charles Hahn]

This is a great reference!