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From: mook johnson on 16 Jan 2010 08:12

"Bob Eld" <nsmontassoc(a)yahoo.com> wrote in message
news:hipunq$h3h$1(a)news.eternal-september.org...
>
> "Jon Slaughter" <Jon_Slaughter(a)Hotmail.com> wrote in message
> news:hipkai$h07$1(a)news.eternal-september.org...
>> 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.
>

+1 on the alcohol recommendation. use an acid brush with the bristles cut
down to 1/2" long. squirt the alcohol inside the hollow brush handle and it
will wick down the bristles while you are scrubbing.

Once the heavy buildup is loose, put paper towel between the board and the
brush and repeat allowing the papertowel to absorb the liquified flus and
alcohol mix.



From: John Larkin on 16 Jan 2010 11:24
On Sat, 16 Jan 2010 07:12:35 -0600, "mook johnson" <mook(a)mook.net>
wrote:

>
>"Bob Eld" <nsmontassoc(a)yahoo.com> wrote in message
>news:hipunq$h3h$1(a)news.eternal-september.org...
>>
>> "Jon Slaughter" <Jon_Slaughter(a)Hotmail.com> wrote in message
>> news:hipkai$h07$1(a)news.eternal-september.org...
>>> 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.
>>
>
>+1 on the alcohol recommendation. use an acid brush with the bristles cut
>down to 1/2" long. squirt the alcohol inside the hollow brush handle and it
>will wick down the bristles while you are scrubbing.

IPA tends to leave white residue when used to clean rosin flux.

>Once the heavy buildup is loose, put paper towel between the board and the
>brush and repeat allowing the papertowel to absorb the liquified flus and
>alcohol mix.

For really clean boards, the last step should be a squirt rinse with
clean solvent.

John

From: John Larkin on 16 Jan 2010 11:25
On Sat, 16 Jan 2010 04:26:27 -0600, "Jon Slaughter"
<Jon_Slaughter(a)Hotmail.com> wrote:

>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 ;)

Unless leakage matters!

John

From: Phil Hobbs on 16 Jan 2010 14:55
On 1/15/2010 6:55 AM, Royston Vasey wrote:
> "Jon Slaughter"<Jon_Slaughter(a)Hotmail.com> wrote in message
> news:hipkai$h07$1(a)news.eternal-september.org...
>> 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'd say no and err on the safe side. Acetone can do nasty things to
> plastics.
>
> Just soak in methylated spirits for a few minutes, much milder on both the
> hardwar and your lungs and fingers.
>
> I'm not sure if the name methylated spirits is used globally - maybe you
> know it as denatured alcohol ???
>
>
>
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.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058

email: hobbs at electrooptical dot net
http://electrooptical.net
From: Tim Williams on 16 Jan 2010 15:13
"Phil Hobbs" <pcdhSpamMeSenseless(a)electrooptical.net> wrote in message
news:Be2dncsbguc1hM_WnZ2dnUVZ_vxi4p2d(a)supernews.com...
>> I'm not sure if the name methylated spirits is used globally - maybe you
>> know it as denatured alcohol ???
>
> 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

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms


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