Ask the Experts
July 31, 2017 - Updated
July 4, 2007 - Originally Posted

Cleaning PCB Boards with window cleaner?

I tried cleaning a PCB assembly with window cleaner. It did a marvelous job. Are there any conductivity issues that would arise if such a solution is used to remove flux residue?


Expert Panel Responses

From your question, I assume you are a fan of survivor. You know the show where people are parachuted onto some tropical island and given "survival" task, like an emergency appendectomy with a conch shell. But seriously, I suspect you are working with water soluble flux. These materials are generally cleanable with water alone, as long as you stay away from lead free materials, hence your apparent success with flux removal. Your question about ionics is most likely yes. Window cleaners use very common place materials (read low cost), and one can reasonably assume they will be ionic. Another concern is water "rinse-ability". My experience with window cleaners is that they leave a film that will eventually either wear off or evaporate. This is generally not preferred at electronics assembly operations. Obviously there is no data on effectiveness, compatibility of such materials and since generating such data is the responsibility of the cleaning agent supplier (in many cases), and you are not likely to get much help on that front from S.C. Johnson or their local agent, Walmart. The real question you need to consider is this: are your savings in cleaning chemistry worth the price you will pay when one of your customers has a field failure and comes back to you as part of their investigation. One suspects that price may well be lost business in the future.

Tom Forsythe
Vice President
Kyzen Corporation
Mr. Forsythe is a recognized expert in cleaning chemistries and processes. Tom has a Bachelor's in Applied Mathematics & Engineering from the US Naval Academy. He is well published in both the industry trade magazines. Tom has spent the last 14 years with Kyzen Corporation.

I would not recommend using window cleaner, if you subject the PCBAs to even the basic cleanliness tests (ionic contamination, SIR, etc.) you will most likely find that, while it appears you removed the flux residue, there's a lot of "bad stuff" left on your board.

Phil Zarrow
Principal Consultant
ITM Consulting
Mr. Zarrow has been involved with PCB assembly for more than thirty years. He is recognized for his expertise in troubleshooting SMT manufacturing and lead-free implementation. He has extensive hands-on experience with set-up and troubleshooting through-hole and SMT processes throughout the world.

I would not recommend a window cleaner to remove flux residues. Window cleaners have different chemicals in them that could be dangerous to the functionality of the product. Some of the cleaners have chlorine in them to make them cut through grease, or ammonia which when they dry will leave residues on the board surface which will be impacted by the moisture in the environment during the operational cycle of the product. These residues could and will impact the insulation resistance properties of the laminate material which will lead to signal integrity problems or worst case short on the surfaces of the boards. Cleaners used to clean off fluxes must be evaluated to determine that they can in fact remove the fluxes and the materials the fluxes are made of and leave no residual residues which could be harmful to the functioning life of the product. There are test which can be conducted to determine board cleanliness and those test should be conducted when evaluating cleaning solvent selection.

Leo Lambert
Vice President, Technical Director
EPTAC Corporation
At EPTAC Corporation, Mr. Lambert oversees content of course offerings, IPC Certification programs and provides customers with expert consultation in electronics manufacturing, including RoHS/WEEE and lead free issues. Leo is also the IPC General Chairman for the Assembly/Joining Process Committee.

Depends on the solution. Some window cleaners are primarily alcohols; others contain a significant amount of weak organic acids. The alcohols can leave films, which won't look pretty, but are rarely a conductivity issue. The weak organics are another story and will depend on the type and amount. The bigger concern is lack of control. The manufacturer of the window cleaner may tweak their formulation and increase or decrease WOA content without informing you. It will have no influence on the "functionality" of windows, but it could have a huge impact on your boards. In summation, don't do it.

Dr. Craig D. Hillman
CEO & Managing Partner
DfR Solutions
Dr. Hillman's specialties include best practices in Design for Reliability, strategies for transitioning to Pb-free, supplier qualification, passive component technology and printed board failure mechanisms.

Since my bottle of Windex doesn't list any ingredients, you would need to contact the manufacturer for details.

Edward Zamborsky
Regional Sales Manager
OK International Inc.
Ed Zamborsky is a Regional Sales & Technical Support Manager for Thermaltronics, located in New York. His position requires frequent customer visits throughout North America and the Caribbean and his position encompasses not only sales but the role of trainer and master applications engineer for all of Thermaltronics products. His expertise includes such specialties as hand soldering, convection and conduction reflow techniques, array rework, fluid dispensing equipment, and fume extraction. Ed has authored many articles and has presented many papers on topics such as; Low Volume SMT Assembly, Solder Fume Extraction, SMT Rework, BGA Rework, Lead-Free Hand Soldering, High Thermal Demand Hand Soldering, Lead Free Visual Inspection and Lead Free Array Rework.

Window cleaner? How visionary! Does it help you find shorts inside the PWB? Do you also use a squeegee? Looking through my window, what do I see? Reliability? Nope. That I don't see!

Richard D. Stadem
Advanced Engineer/Scientist
General Dynamics
Richard D. Stadem is an advanced engineer/scientist for General Dynamics and is also a consulting engineer for other companies. He has 38 years of engineering experience having worked for Honeywell, ADC, Pemstar (now Benchmark), Analog Technologies, and General Dynamics.
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