Paul Drahn wrote:
On 11/16/2011 6:42 PM, mike wrote:
Ron wrote:
On Nov 16, 8:03 pm, gregz wrote:

That being said, sometimes after I wash electronics with water, Then
spray
with wd40, and continue drying with heat.

What electronics do you wash with water?

Much of the electronics in the world has been washed in water as
part of the assembly process.
There are components that can't stand it, so you gotta be careful.
I wash circuit boards in Simple Green cleaner, then alcohol then water
then do it again. Blow off the water with compressed air between washes,
then repeat again. Some gunk is soluble in simple green, some in alcohol,
you need both.
Scrub with a toothbrush at every stage.
Doesn't do much good to dissolve the stuff then let the solvent evaporate.
Blowing off is critical to the process. Get all the liquid out from
under parts. Space under a surface mount IC can be tiny.
Dry it then dry it again then dry it some more.
Works wonders on removing residue from leaky electrolytic capacitors.

Some people use the dishwasher. I don't because It's harder to mask
components that can't be washed.
General rules of thumb include:
1)don't get solvent into anything that changes properties under the
influence.
2)don't get solvent into electromechanical stuff.
3)don't get solvent into anything that it can't easily get out of.
It's really easy to let contaminated solvent seep into a switch, but
it's very
difficult to get it ALL out. Evaporation is not an option, cause
the process deposits more gunk and leaves it behind.
That's what we do. Wash all boards with hot deionized water in a
commercial board washer. I think the temp is around 140 degrees F. Looks
like a very expensive dish washer. All water is recirculated through
tanks to clean and deionize the water. We have a regular Sears dish
washer for backup and that water goes down the drain.

After the washer tries to dry the boards, the excess water is blown off
using deionized compressed air, being extra careful to clear all water
from under components. After that, they are air dried for a while.

All components that can't be washed are hand added after washing. Flux
from that operation is cleaned with IPA, isopropal alcohol. Sometimes a
manufacturer fails to state on their component spec sheet that the unit
can't be washed and then there is trouble, but most do tell you.

Paul

Had some problems with some German caps that were not totally sealed. From
the board manufacturer had leakage that didn't work with the circuit which
did not tolerate leakage. Had to replace each by hand. Even had board
leakage under components. Switched to another type cap and got better
washings, problems went away.

Deionized compressed air. I like that one. I think my solder station had
that, and heated with temperature settings. Often used 100 watt bulb to
bake boards.



Greg