DIYbanter - View Single Post - Cell Phone -- What remains wet?

Jim Adney

On Wed, 25 Jun 2008 15:42:52 GMT (GregS)
wrote:

I have cleaned stubborn high impedance loading by using mostly alcohol
and the Weller air pencil set to a high flow and low temperature. The problems
were under the components. I sometimes have to repeat many times
before all the flux and residue is out. You have to move the air pencil around
under components, going mostly in one direction. The old boss made me use alcohol.

Rosin flux doesn't dissolve completely in either water or alcohol, but
I've found that by alternating rinses, I can eventually remove it. In
cases like that, it might pay to invest in commercial flux remover, if
only to get things started. I'd still finish up with water and then
alcohol, however.

By the way, the cell phone I worked with appears to be OK after much cleaning, cyclic baking, and
a month delay.

In that case, there was probably something on the board that was just
hard to get the water out of. The real test will be to see whether it
continues to work in humid weather. That's when residue can resorb
moisture and start causing problems again.

If there's no residue, then humid weather should not cause any
problems.

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Jim Adney
Madison, WI 53711 USA
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