Seven stages.One sound foundation.
A chromium-free immersion sequence designed to remove contamination, condition the aluminium and establish the surface required for durable powder-coat adhesion.
- Stages
- Seven-stage immersion
- Chemistry
- Chemetall Gardobond X4707
- System
- Chromium-free conversion
01 / Why it matters
The finish starts
before the powder.
Incoming aluminium can carry oil, silicone, process residues and natural oxidation. If these remain, the visible finish may conceal a compromised bond.
Swallow uses a seven-stage immersion process to etch, rinse and convert the surface in sequence. De-ionised-water conductivity is controlled at key points, with the final rinse maintained below the stated process limit.
The result is a prepared substrate ready for the specified architectural polyester system.
Surface principle
Remove what should not be there. Convert what remains.
Pre-treatment parameters are monitored as part of the connected production and laboratory process.
02 / Immersion sequence
Measured from
stage one to seven.
The sequence progresses from surface etching through controlled rinsing to chromium-free conversion and the final low-conductivity rinse.
- 01
Caustic etch
Initial surface etch and preparation.
- 02
Mains water
Primary rinse after the first etch.
- 03
Acid etch
Further surface conditioning.
- 04
DI water
De-ionised rinse.
- 05
DI water <200 µS
Controlled-conductivity rinse.
- 06
Chromium-free conversion
Chemetall Gardobond X4707 treatment.
- 07
DI water <30 µS
Final low-conductivity rinse before coating.
03 / Process controls
A clean surface is only the beginning.
- Contamination
- Oil and silicone
The immersion sequence addresses common residues carried by supplied aluminium profiles.
- Oxidation
- Etched and conditioned
Natural surface oxidation is treated before conversion and powder application.
- Water quality
- Conductivity limits
De-ionised rinses include controlled stages below 200 µS and 30 µS.
- Conversion
- Chromium-free
Gardobond X4707 technology forms the conversion stage of the sequence.
- Integration
- One facility
Pre-treatment, application and testing operate as one connected workflow in Elland.
- Verification
- Process monitored
Laboratory controls support chemical management and finished-coating assessment.
Specify the finish.
Protect the foundation.
Talk to Swallow about the alloy, section, exposure environment and complete coating system.