ultrasonic PCB cleaning, white residue - Page 1
Forum section: electronics / general

author: teus
author_rank: Contributor
timestamp: June 21, 2020, 01:19:41 pm
content: Yeah, there's only a million topics about white residue from trying to clean flux, but I still get it when using an ultrasonic cleaner and "Shesto Ultrasonic Cleaner Solution For Flux Remover and PCB". Several kinds of solder paste never cause problems, but the white residue comes from the solder wire for through-hole components (Stannol TRILENCE 2708 REM1).I'm looking for some insight why it's not working.I mix the Shesto correctly with distilled water, bring it to 40~60C for the ultrasonic machine, and use IPA to displace all the water. Cleaning baths in between steps don't help. Treating PCB's with a spraycan of Cramolin Flux-off actually helps: I scrub it well, apply more, then rinse. Combining this with ultrasonic cleaning, IPA and rinsing... it's a stupid amount of work.I rather not change the solder wire, since it takes some patience to find something suitable. I produce PCB's in small quantities, and trial + error is expensive when ultrasonic cleaners are mostly sold in gallon or 5L bottles and shipping is _very_ expensive. The Shesto is available in 1L bottles and I could get it easily with free shipping.Datasheets can be found here:https://be.farnell.com/shesto/utflu01/cleaner-flux-remover-bottle-1l/dp/2759031https://be.farnell.com/stannol/trilence-2708-0-5mm-rem1/solder-wire-96-5-3-0-5-sn-ag-cu/dp/2532576?st=2708%20trilencehttps://benl.rs-online.com/web/p/flux-removers/1115843/

author: Ian.M
author_rank: Super Contributor
timestamp: June 21, 2020, 02:15:46 pm
content: Stannol says the flux is halide activated synthetic resin composition, and if you are getting streaking from a reasonably fresh and clean cleaning solution, it would seem likely that your solution is only partially emulsifying the flux resin. Have you tried Stannol's recommended Stannol Flux-Ex 200/B. cleaner?

author: teus
author_rank: Contributor
timestamp: June 21, 2020, 02:31:01 pm
content: Quote from: Ian.M on June 21, 2020, 02:15:46 pmalright, that's interesting. the solution is freshly made and super clean.I haven't tried Stannol's cleaner yet, because I don't see it for sale anywhere. I find some datasheets here and there, or some wholesale suppliers, but otherwise it seems like it doesn't exist at all.

author: all_repair
author_rank: Frequent Contributor
timestamp: June 21, 2020, 03:39:18 pm
content: How did you do the rinsing? How clean is the distilled water?

author: teus
author_rank: Contributor
timestamp: June 21, 2020, 03:43:35 pm
content: Quote from: all_repair on June 21, 2020, 03:39:18 pmfresh distilled water, plastic box with toothbrush.

author: jmelson
author_rank: Super Contributor
timestamp: June 21, 2020, 11:00:32 pm
content: Quote from: teus on June 21, 2020, 01:19:41 pmI have some boards that are tested in a bed of nails fixture. I had problems with flux preventing the pogo pins from making contact. I now solder those through-hole parts with WS wire solder, and then the flux just washes off with a little water. It is totally amazing, and leaves thos contacts totally clean. That solder is by AIM. (WS = Water Soluble)I also use liquid flux to dip-solder a board that has 40 through connectors, and then wash in water. This board also comes out very clean after just a few seconds of washing.Jon

author: wraper
author_rank: Unknown
timestamp: June 21, 2020, 11:06:19 pm
content: Shesto cleaner is garbage. I bought one bottle of it for testing and it does not remove rosin based flux residues well, especially when diluted as per instructions. Try real industrial PCB cleaner like Electrolube SWAS. It's like day and night difference.

author: all_repair
author_rank: Frequent Contributor
timestamp: June 21, 2020, 11:24:00 pm
content: https://be.farnell.com/electrolube/swat05l/cleaning-safewash-total-swat-5l/dp/1961586?st=Pcb%20cleanerI used this. If I did not do rinsing well I got the white patch too. No need IPA, IPA worsen it. Last rinse with clean distilled water make the difference for me.I kept the soiled swat05l and reuse them for other less stringent cleaning. It is a powerful detergent.

author: teus
author_rank: Contributor
timestamp: June 22, 2020, 04:27:33 pm
content: Quote from: wraper on June 21, 2020, 11:06:19 pmShesto garbage? alright, simple enough.Quote from: all_repair on June 21, 2020, 11:24:00 pm146 euro? fucking hell, that's too expensive.RS sells 1L of homebrand cleaner, which is used undiluted. might be worth trying.https://benl.rs-online.com/web/p/ultrasonic-cleaning-fluids/1365783/

author: eb4fbz
author_rank: Regular Contributor
timestamp: June 22, 2020, 10:00:49 pm
content: I use EMAG EM-303. Cheap and easy to buy in 500mL bottles. Give it a try. But some flux residues are very hard to remove.

author: all_repair
author_rank: Frequent Contributor
timestamp: June 23, 2020, 10:02:51 am
content: I bought from e14 singapore, price is cheaperhttps://sg.element14.com/electrolube/swas05l/cleanser-aqueous-super-swas-5l/dp/725687?ost=safewashbut the expiry date is 2 week on delivery.https://sg.rs-online.com/web/p/precision-cleaners-degreasers/2173841/looks similar

author: IconicPCB
author_rank: Super Contributor
timestamp: June 23, 2020, 10:52:59 am
content: Mineral turpentine and elbow grease followed by a aqueous wash and rinse in DI water.

author: teus
author_rank: Contributor
timestamp: June 23, 2020, 02:22:05 pm
content: Quote from: eb4fbz on June 22, 2020, 10:00:49 pmlooks good. reichelt.de has it, shipping cost should be reasonable.