6 FAQs about flux removers: essential insights for benchtop cleaning success

Elizabeth Norwood, Senior Chemist at MicroCare, LLC, further explores.

Leftover flux residue can pose a variety of risks to PCBAs, including corrosion, signal interference, and even part failure. With a range of options available, it’s crucial to understand the different types of flux removers, their costs, safety considerations, and environmental impact to choose the right product for your needs. Here are common questions about flux removers to help you make informed and effective cleaning decisions.

1. Why is flux remover necessary?

Flux removers play a critical role in eliminating contaminants left behind after the soldering process. During soldering, flux is used to remove oxidation from metal surfaces and help the bonding of solder to the metal. However, once the solder joint is complete, the remaining flux residue – composed of oils, greases, or solder paste – can be detrimental to the PCBA. These residues can cause corrosion, short circuits, signal interference, and reduced component lifespan. In applications where electronic reliability is essential, like medical devices or aerospace technology, not removing flux residues could lead to device failure or even safety hazards.

Effective removal of contaminants enhances the long-term PCBA reliability by preventing corrosion and other issues that may otherwise develop over time. However, not all flux removers are compatible with every material; using the wrong cleaner could potentially harm sensitive components. Ensuring compatibility by checking product specifications and following best practices is key to avoiding unwanted damage and achieving the best results.

2. How do I choose the right flux remover?

Choosing the right flux remover depends on factors like the type of flux used (e.g., rosin, lead-free, no-clean, water-soluble) and your cleaning method. Some flux removers are versatile enough to manage multiple flux types, while others are more targeted.

Also, consider the materials being cleaned, as some removers can damage sensitive plastics or metals. Ensure the remover suits your cleaning method and meets any environmental or safety requirements.

Consulting with a cleaning fluids supplier is invaluable for selecting the right cleaning solution tailored to your needs. These experts can help match the cleaning fluid to your specific contaminants, provide guidance on material compatibility, and recommend cleaning fluids based on your method. This collaboration ensures you achieve effective cleaning results while supporting the integrity of your components and equipment.

3. What types of flux removers are available?

Flux removers come in different forms, each suited to specific cleaning requirements and applications. The four primary types of flux removers are aerosols, pre-saturated wipes and pens.

• Aerosols are convenient for board cleaning and are ideal for reaching under low-mounted board components to access all parts of an assembly. Spray applications allow for quick, targeted cleaning, but proper ventilation is essential due to potential fume release. Using a specialty cleaning fluid delivery tool targets contaminated areas, minimising waste and ensuring thorough cleaning. It reduces cleaning time, improves consistency, and enhances operator safety by limiting exposure to chemicals

• Pre-saturated wipes are ideal for quick, manual cleanups on small components
• Flux Remover Pens are for precision cleaning in small areas, particularly useful for delicate circuit board areas or component edges

To ensure effective residue removal, it’s essential to follow the manufacturer’s instructions regarding application methods, cleaning times, and compatibility guidelines. Depending on the application, added testing such as ionic contamination or surface insulation resistance (SIR) testing might be called for to verify cleanliness levels. Using magnification or inspection lighting after cleaning can help ensure no residues remain. 

4. How much do aerosol flux removers cost?

Aerosol flux remover prices vary based on can size, formulation, and purity. Nonflammable options generally cost more due to added safety features. Smaller cans are convenient but often have a higher per-ounce cost, while larger cans can bring the cost-per-clean down.

Bulk purchasing can yield significant savings, as larger cans reduce the need for frequent restocking, lower the cost per cleaning, and reduce operational downtime. Some flux removers also have an indefinite shelf life if stored correctly, cutting product waste due to expiration.

5. What safety precautions should I take when using flux removers?

When working with flux removers, always use them in a well-ventilated area to prevent the accumulation of fumes. Personal protective equipment (PPE), such as gloves and safety glasses, is essential to prevent contact with skin or eyes, as many flux removers have chemicals that can cause irritation.

In addition, it’s crucial to follow the product’s safety data sheet (SDS) guidelines and store flux removers away from heat sources and direct sunlight to reduce the risk of accidental ignition. Be aware of local regulations and guidelines concerning the storage and disposal of hazardous materials to ensure compliance with safety standards.

6. Are there environmental or regulatory concerns when using flux removers?

Environmental impact is a key factor when choosing a flux remover. Eco-friendly options with low global warming potential (GWP), zero ozone-depleting potential (ODP), and non-toxic ingredients are preferable, reducing environmental harm and health risks. Conversely, some removers have aggressive chemicals needing special handling and disposal.

Choosing an eco-friendly flux remover that meets your environmental goals and regulatory standards helps reduce compliance costs and minimise environmental liabilities

Conclusion

In summary, flux removers play an essential role in ensuring the functionality and reliability of electronic devices by removing residues from PCBAs left after soldering. Choosing the right flux remover requires a careful balance of factors, including the type of flux, compatibility with components, cleaning method, and cost. Additionally, attention to safety and environmental impact is paramount to safeguarding user health and supporting sustainability efforts.

By selecting a product that meets your cleaning needs, buying in bulk to improve costs, and following recommended safety and environmental guidelines, you can enhance cleaning processes, minimize waste, and support compliance. Consulting with flux remover manufacturers or suppliers can offer valuable guidance in selecting the best solutions tailored to your unique requirements.