I think this has been asked before, so sorry if I rehash the same old question.

I just soldered a TQFP-64 component and the results look pretty good. Until I zoom in and notice the leftover solder paste.

I've tried IPA, scrubbing, etc. but I just can't get to the blobs of solder paste between the pins and near the body of the component.

Recently, I've used a jewelry cleaner to clean some keyboard keys (works amazing...BTW). So I was thinking of dropping this little board into that and fill it with IPA.

What are you thoughts on that? Or, do you have a better idea?

I don't have any official flux cleaner. Only IPA and the cleaner that came with the jewelry cleaner.

The IPA I have is 99.1% pure.

Suggestions welcomed!

Thanks.

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Cat; the other white meat.

I've done quite a bit of PCB assembly over the decades, both through hole and SMT boards. In all cases, I've used a proper flux remover. For some of the SMT parts, I use some small cotton lint-free cleaning patches (normally for cleaning firearms) with flux remover and ensure the junk is out from between the leads. Once cleaned, I use a heat gun to lightly warm the PCB which gets rid of the condensation that forms from the flux remover, which makes the PCB quite cold. It's generally a fairly quick and painless task.

For the past 8-10 years, I've been using Techspray G3, p/n 1631-16S. It's also RoHS compliant.

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Regards, KM
https://github.com/floobydust

Alcohol is not a terribly effective flux remover. I use a product called Flux-Off Aqueous by Chemtronics. I bought a gallon of this stuff from Mouser about 7 years ago and it's just amazing. You mix it 10 to 1 with water so a gallon will last you a long, long time. The $55 it cost for the gallon is cheap like borscht. I currently use it in a small (3 liter) ultrasonic cleaner but initially just used it in a PE container I got at the dollar store. Before putting my board(s) in it I'd warm up the solution in a microwave to about 40C, pop the boards in for 20 minutes, lightly scrub with a toothbrush, rinse in hot water and let dry on a paper towel. Perfect results.

Just checked, and in 7 years I've only used a quart of it, and for 4 of those years I used it in a small manufacturing thing I had going. Hundreds of ( small) boards every month. Very effective, very economical.

Oh, and it's not terribly toxic, nor does it have any strong odor, especially once mixed. Unlike those spray-can flux cleaners.

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Bill

Thanks for the suggestions!

On that Flux-Off, how do you dispose of it?

We're on a septic tank so I make sure I never pour flammable liquids down the sink. I'm not sure if our local recycle center would take it. They take oil and gas. I can ask.

Thanks!

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Cat; the other white meat.

We have a hazardous waste depot near us. I just save it up in old gallon jugs and take it there. Before you use it it is not considered very toxic, but after use it may have lead and other undesirable residue in it, so I just take it there. Does not cost me anything. Not sure what the situation is in your area.

It's not flammable - not even close. The bacteria in a septic system may be able to deal with the tiny amounts of rosin and lead and make them pretty harmless. You'd need to do some more research on that.

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Bill