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How to use Leather Filler

What is Leather Filler?

Leather Hero leather filler (Fill No.14) is a flexible, sandable, water-based, air-drying compound with excellent adhesion properties for filling surface imperfections in leather. It has a white base and comes in a variety of colours.

Compatability

It is designed to be used under leather paint to create discreet repairs and surface corrections. Due to its opaque qualities, it is suitable for use under opaque finishes and not generally suitable for use under transparent finishes.

Suitable ForNot or Less Suitable For
Finishing SystemLeather Paint (Colour No.6)Aniline Dyes & Stains (No.)
Leather Repair KitsAniline Dye & Colour Restoration Kit (No.)
Topcoat (clear coating only)
Leather TypePigmented Nubuck
Man-made leatherSuede
Aniline
Semi-aniline

Types of filling

There are 2 main occassions to use leather filler:

  1. Rips and tears: when accidents happen (scissors, knives etc) or when a tear occurs in weakened leather
  2. Surface corrections: when the surface has imperfections such as delamination, scuffs, scratches and other such textural irregularities

In this guide, we will focus on the second type of usage as it is the most common.

The finish on these seats is delaminating, making them look old and worn

How to use Leather Filler

Good surface prep is an important part of successful results, including filled repairs.

  1. Clean the leather surface with Spot & Prep (No.4)
  2. Glue closed any loose tags or open tears with Glue (No.16) and allow drying. Repeat until glueing is completed
  3. At this stage and throughout the process, you can sand to smooth the area using a 400-800 grit sandpaper
  4. Load some filler onto the back of a palette knife then drag the knife on a 20-45 degree angle across the repair area, pressing firmly and evenly so that a neat, thin layer of filler is deposited. Allow drying
  5. When dry, the filler can be sanded to smooth the area
  6. Continue applying Fill (No.14) in thin layers until the repair or surface imperfections are filled and smooth

Optional steps

  • Apply leather Binder (No.33) before applying Fill (No.14) to stabilise loose, flaking, open and porous leather. It can be sanded, helping to seal and smooth a rough and unstable surface before filling
  • Mix around 10% Leather Paint (Colour No.6) into white Leather Filler to tint it
  • Apply a final layer of filler and texturise by dabbing with a sponge to stipple the surface to mimic leather grain
  • Insert a sub-patch behind a tear. Use a palette knife or similar to flatten the patch so that it lies flat under the leather. Use Leather Glue (Glue No.16) to join a small margin of leather around the tear to the backing patch then apply more glue to join the edges of the tear back together. When the glue is cured, apply Fill (No.15) as described previously.
    • Suitable sub-patch materials include leather, vinyl, mesh, interfacing or fabric

Here we track the progress of a lounge restoration from worn and delaminated to fully refinished and vastly improved.

1) Before: Delamination
2) Cleaned and sanded
3) 2 coats of Binder (No.33)
4) Mix of Fill (No.15) and Colour (No.6)
5) Blended to create a tinted filler
6) Applying filler
7) Firm and even pressure
8) Filling in layers
9) Refinish using Prime (No.5), Colour (No.6) and Topcoat (No.7)

Troubleshooting

  • Leather filler is not designed for rebuilding missing leather. Using a patch then filling to cosmetically improve the joins is preferable to attempting to lay in large areas of filler
  • Oil in leather prevents coatings and compounds from forming a bond. If your leather is very oily, it may appear dark in colour and soggy or spongey to touch
  • Filler that it applied too thickly, may not cure. Thin layers are recommended
  • Filler that is not dry, may not sand well. Allow to cure properly then, when cured, sand as needed
  • Repaired area looks smooth. This is normal where a lot of filler has been used or when the grain is smooth. Try stippling to mimic leather grain if needed
  • Repaired area feels a little stiffer than the surrounding leather. Depending on the size of the repair, this can be the case. Cured repairs may relax as the leather flexes with use

What to expect

Leather Filler (Fill (No.14) can produce very rewarding repairs. When an accidental tear happens in leather that is in good condition, a carefully glued, filled and refinished repair can conceal virtually all evidence of the tear. When leather is aged and no longer in great condition, filling can soften textural imperfections to improve the surface before refinishing.

This Before and After comparison clearly shows a dramatic improvement in the appearance of the leather upholstery

When it comes to rips and tears, perfectly undetectable repairs are possible but rare. In contrast, results that deliver significantly improved outcomes are common and perfectly achievable in most cases. With older leather, when you aim for an overall improvement in the look and feel of your leather as well as an extension of the usable life of your upholstery, handbag or car seats, a lot can be achieved.

The finished result was very impressive and extremely rewarding