The raw edge is one of the most closely examined areas of a leather item, and one of the most sensitive in series. Finishing the edges in leather goods and footwear, whether by smoothing or burnishing, serves three purposes:

• Binding the leather fibers to create an edge that is smooth to the touch and to the eye, identical from one piece to the next.
• Protecting the edge against moisture and friction, the primary causes of wear and returns.
• Ensuring a consistent finish across an entire batch: regularity is what a manufacturer controls.
  

  À gauche, une tranche brute et fibreuse ; à droite, la même tranche après lissage et brunissage à la gomme 4000/1.

The 4000/1 is a water-based burnishing gum that binds the fibers and seals the edge through polishing. Three uses for a single product code, from prototype to series.

Technical specifications

• Water-based, odorless: comfortable application at the workstation, without harsh solvents.
• Paste-like viscosity of 4,000 to 5,000 mPas: the product stays on the edge without running, for a controlled deposit.
• Water-dilutable: you set a constant consistency, and therefore a reproducible result.
• Natural wax content: a flexible film that conforms to the leather and does not crack over time.

Production benefits

• Process stability: a consistent formulation batch after batch, for settings that do not drift.
• Ease of use in series: quick integration at workstation level, without complex equipment.
• Consistent quality: an identical edge from one piece to the next, ensuring compliance.

Three uses for a single product

• Edge finishing: a clean, smooth edge with a natural shine.
• Flesh-side sealing: a smooth, durable surface on the flesh side, with no fluffing.
• Surface finishing on smooth leather: a subtle top finish.

1. Prepare the edge by bevelling, then lightly sanding it.
2. Apply a thin coat using a felt tip, brush, pad or applicator, then spread it evenly.
3. As soon as it begins to dry, smooth it with a burnishing tool: this burnishing step tightens the leather fibers.
4. Once dry, polish with a cloth, without applying heavy pressure.

For a colored edge, dye the edge first, then apply the 4000/1 as a finishing step. For series production, use the same dilution and the same deposit thickness to ensure consistent results.

In production, consistency comes from the process, not the amount of product used. Lock in a single dilution ratio, a thin application layer and a consistent drying time before polishing, then validate these settings on a test batch before starting series production. Our R&D team adapts the consistency of the 4000/1 to your substrate and production rate: this has been our craft as a manufacturer since 1900.

Whether working with vegetable-tanned or recycled leather, always test the gum on a sample piece before full production. A thin, well-smoothed layer performs better than a thick one: you gain consistency and shine without overloading the surface.

For leather goods (bags, wallets, belts), in footwear manufacturing and on recycled leather materials, which are often heterogeneous, the 4000/1 evens out the edge and complements your range of finishing products.

Designed for industrial series production, the 4000/1 brings workshop-level burnishing performance into a mass-production environment: a smooth, durable edge, but at production speed, with the repeatability and consistency expected on production lines.

This gum is part of the low-VOC, water-based industrial chemistry developed by Keck Chimie, a French manufacturer of chemical products since 1900.

What is a burnishing gum for leather edge finishing?
A product that binds the fibers of the raw edge to create a smooth, glossy and durable finish.

Is the 4000/1 suitable for series production?
Yes. Its water-dilutable formula ensures consistent viscosity and a repeatable edge quality at the line’s production rate.

Does the 4000/1 contain harsh solvents?
No, it is a water-based, odorless, low-VOC formulation.

On which types of leather can it be used?
Leather goods, footwear and recycled leather, ideally on vegetable-tanned leather, after testing on a sample.

How can consistent results be guaranteed from one batch to the next?
By keeping the same dilution ratio, deposit thickness and drying time at every workstation.

How long does it last?
6 months, sealed and stored in a cool place, never below 5 °C.