By Tony Masci
At SMT Supplies, we work closely with manufacturers across the country. We've noticed a clear regional trend: water-soluble flux is significantly more popular in California than in many other parts of the U.S. While no-clean fluxes dominate in some regions due to their convenience and lower cleaning requirements, California's electronics manufacturers continue to rely heavily on water-soluble alternatives. So why the difference?
Here are some key reasons:
1. Stringent Quality and Inspection Requirements
California is home to a large number of companies in the aerospace, medical device, and defense industries, all of which demand high reliability and have strict standards for cleanliness. Water-soluble flux is easily removed with deionized water, making it ideal for applications where ionic contamination must be minimized and post-solder residues are unacceptable.
2. Access to Water and Infrastructure for Cleaning
Many facilities in California already have infrastructure for in-line or batch aqueous cleaning, making it easier and more cost-effective to use water-soluble flux. In contrast, in regions where such systems are not already in place, manufacturers may opt for no-clean options to avoid investing in cleaning equipment.
3. Tighter Regulatory Oversight
California’s environmental and worker safety regulations, including those enforced by Cal/OSHA and CARB (California Air Resources Board), can discourage the use of certain solvents used in cleaning no-clean residues. Water-soluble flux, when followed by an aqueous cleaning process, can provide a safer and more environmentally compliant solution.
4. Cultural and Industry Preferences
There is a long-standing preference in California for high-performance fluxes that offer robust wetting, even if they require an extra cleaning step. Water-soluble flux is known for excellent soldering performance, especially on difficult-to-solder surfaces, and that reputation has stuck.
5. Higher Concentration of Contract Manufacturers
California has a large number of EMS and contract manufacturing firms that serve demanding OEMs. These customers often specify cleaning requirements in their documentation, and water-soluble flux is preferred when flux residue must be fully removed to meet those specs.
Final Thoughts
While no-clean flux certainly has its place, California’s unique mix of regulatory demands, advanced manufacturing sectors, and quality expectations makes water-soluble flux the go-to choice for many local manufacturers. Contact SMT Supplies, we stock a wide range of fluxes from AIM Solder to meet the needs of both water-soluble and no-clean applications, no matter where you're located.