PCB Cleaning

[Jon Slaughter]

Is it safe to soak a pcb in acetone for several minutes to clean it up all
the flux? The board only has some QFN's, SMT LED's, and passive SMT's. I
imagine the acetone won't harm these packages?

 

[Bob Eld]

Is it safe to soak a pcb in acetone for several minutes to clean it up all
the flux? The board only has some QFN's, SMT LED's, and passive SMT's. I
imagine the acetone won't harm these packages?

I think acetone, MEK and similar solvents are too harsh. They can dissolve
or swell some plastics and may damage components.

I use 91% isopropyl alcohol or denatured ethanol both are mild and work
well. Use a small brush to loosen flux then wipe with a soft clean cloth.
Re-do if any residue remains.

 

[Archimedes' Lever]

Is it safe to soak a pcb in acetone for several minutes to clean it up all
the flux? The board only has some QFN's, SMT LED's, and passive SMT's. I
imagine the acetone won't harm these packages?

Do you think the epoxy used in making the PCB might react?

I would not "soak" anything in a solvent other than something like a
metal or other NON-porous material.

PCB material is VERY porous, even though it may not appear so.

It is epoxy and fiberglass.

 

[Archimedes' Lever]

I've never seen a pcb be affected by a short time in acetone.

"...soak for several minutes" is NOT "a short time".

 

[Jon Slaughter]

Alcohol worked pretty well. It left a small amount of residue in some
areas(white stuff which I have no what it is) and didn't get teh really
burned flux off well. I'd say it was about 97-99% effective in removing the
flux but not greating in making a pretty board. Luckily I only care about
looks with my women

 

[Tim Williams]

Not the same thing. Methylated spirits is methanol, denatured alcohol is
ethanol with something really bad tasting added--used to be benzene, now
usually kerosene IIRC.

No,
"Traditionally, the main additive is 10% methanol, giving rise to the term
methylated spirit"

Denatured, in general, can include bitter stuff, but AFIAK benzene and such
were removed a long time ago because people kept dying or something. OTOH,
the article also says British regs add mineral spirits.
http://en.wikipedia.org/wiki/Denatured_alcohol

Tim

 

[Mycelium]

By alcohol I was referrring to 190 proof Everclear from the liquor store.
Seem I always have some handy for some reason. Keep the cap closed tight so
it doesn't absorb water.

I've never had a problem with white residue.

Grain alcohol and isopropyl alcohol (IPA) are two entirely different
molecules. One is for drinking, and the other is the solvent, and is
used in labs.

 

[jadu]

jadu had written this in response to
http://www.electrondepot.com/electrodesign/Re-PCB-Cleaning-450232-.htm :

John Larkin wrote:





-------------------------------------
Nice article If you are interested you can visit the
www.leelaelectronics.in and
browse many ultrasonic cleaners. Not just ultra sonic PCB cleaners but you
will
find many types of ultrasonic cleaners like table top cleaners , larger
ultrasonic
& other applications


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[JosephKK]

IPA dissolves the rosin. The white stuff left over is not soluble in
IPA
but is soluble in water. I always follow IPA cleaning with a good
scrubbing
w/toothbrush and warm water then blow dry. Baking in warm oven is
optional.
al

Ah, so that is why some people have told be to use (distilled / deionized)
water for the last rinse.

 

[Archimedes' Lever]

Ah, so that is why some people have told be to use (distilled / deionized)
water for the last rinse.

If the final IPA rinse is with clean enough IPA and nothing is left on
the board, there will be nothing to form any halo with.