Cleaning and degreasing before coating and bonding: choosing the right cleaner
Bonding and coating only succeed on clean surfaces. Grease, release agents, or particles prevent adhesion; even the best adhesive or paint will then fail. This article shows which contaminants interfere, which cleaners are available, and how to select the right one.
At a Glance: Why Cleaning Before Joining
Adhesion occurs through direct contact between the adhesive or coating and the substrate. A thin layer of grease or release agent is sufficient to prevent this contact. Therefore, cleaning and degreasing are not a secondary step but a prerequisite for a durable bond.
Which Contaminants Interfere
- Greases and oils from manufacturing, handling, or corrosion protection.
- Release agents and silicone residues, which specifically prevent adhesion.
- Particles and Dust from machining and the environment.
- Old adhesive and sealant residues from repair and maintenance.
Cleaner Types at a Glance
| Cleaner type | Suitability | Example from the Product Range |
|---|---|---|
| Solvent-based cleaners | fast, grease-dissolving, volatile | Technical acetone, special cleaner 750 |
| All-Purpose and Industrial Cleaners | gentle on materials, for machines and surfaces | Technomelt Melt-O-Clean |
| Special remover | Silicone and adhesive residues, cured seals | Seal and Bond Remover |
| PU cleaner | Fresh polyurethane residues | EN 705 and EN 706 PU-Cleaner |
Choosing the right cleaner
Four questions lead to the choice: What type of contamination is present? What is the substrate, and can it withstand the solvent? What subsequent process is involved—bonding, coating, or painting? How residue-free must it be? Solvents can attack certain plastics, so check compatibility with the substrate. The safety data sheet and the manufacturer's instructions for use and protective measures are decisive.
Cleaning correctly: the steps
- Remove coarse dirt mechanically.
- Work with a suitable cleaner and a clean, lint-free cloth, changing the cloth frequently.
- If necessary, clean several times until the cloth remains clean.
- Allow the cleaner to fully evaporate and dry.
- Do not touch the cleaned surface with bare hands again and process it promptly.
Typical errors
- Dirty cloth: the grease is spread instead of removed.
- If the cleaner has not evaporated, residues will impair adhesion.
- The cleaned surface has been touched again.
- An unsuitable cleaner attacks the substrate.
- Silicone or release agent residues not removed.
We will be happy to clarify which cleaner is suitable for your substrate and subsequent process. For preparation specifically before bonding and for removing residues, please see the linked articles.
