Cleaning PCBs - dishwasher rinse?

[Richard]

What are your favorite techniques for cleaning PCBs after assembly?
Especially for getting the flux residue from under surface-mount parts.

How far-fetched are the suggestions to use a dishwasher rinse / dry
cycle? Does this really work? Are there any drawbacks, if your flux is
water soluable? (Like, will I poison my dishware? ;-)


I've seen plenty of warnings that flux (especially fast-acting) is
corrosive enough to eat traces after a few months if not cleaned. I
normally use an RA flux pen that's "non-corrosive", but it still needs
cleanup. http://www.mgchemicals.com/products/835p.html

 

[Leon Heller]

What are your favorite techniques for cleaning PCBs after assembly?
Especially for getting the flux residue from under surface-mount parts.

How far-fetched are the suggestions to use a dishwasher rinse / dry
cycle? Does this really work? Are there any drawbacks, if your flux is
water soluable? (Like, will I poison my dishware? ;-)


I've seen plenty of warnings that flux (especially fast-acting) is
corrosive enough to eat traces after a few months if not cleaned. I
normally use an RA flux pen that's "non-corrosive", but it still needs
cleanup. http://www.mgchemicals.com/products/835p.html

Quite a few years ago I visited a company that used a washing machine to
remove water-soluble flux from their assembled PCBs.


Leon

 

[Boris Mohar]

What are your favorite techniques for cleaning PCBs after assembly?
Especially for getting the flux residue from under surface-mount parts.

How far-fetched are the suggestions to use a dishwasher rinse / dry
cycle? Does this really work? Are there any drawbacks, if your flux is
water soluable? (Like, will I poison my dishware? ;-)


I've seen plenty of warnings that flux (especially fast-acting) is
corrosive enough to eat traces after a few months if not cleaned. I
normally use an RA flux pen that's "non-corrosive", but it still needs
cleanup. http://www.mgchemicals.com/products/835p.html

Dishwasher is frequently used. For smaller jobs I use electric toothbrush
for removing water soluble flux.. Blow off with compressed air.




Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs http://www3.sympatico.ca/borism/
Aurora, Ontario

 

[CFoley1064]

Quoted from Richard [email protected]

How far-fetched are the suggestions to use a dishwasher rinse / dry
cycle? Does this really work? Are there any drawbacks, if your flux is
water soluable? (Like, will I poison my dishware? ;-)


I've seen plenty of warnings that flux (especially fast-acting) is
corrosive enough to eat traces after a few months if not cleaned. I
normally use an RA flux pen that's "non-corrosive", but it still needs
cleanup. http://www.mgchemicals.com/products/835p.html

Many fluxes are corrosive (especially in the presence of any heat, either the
components themselves or self-heating of traces). A dishwasher is a good idea
for water-soluble fluxes. They won't hurt the pipes, pump, or mechanisms of
the dishwasher, but most fluxes are not good for you, so don't wash the boards
with dishware. Since these are water-soluble, flux residues shouldn't stick to
the dishwasher surfaces, but to be safe I'd run the dishwasher through a full
cycle with detergent empty before using it for dishes again). Your biggest
"gotcha" will be whether all of the parts on your board can handle the water.
For instance, you might have a relay, DIP switch or potentiometer on the board
that will absorb water, and will either fail or not work correctly. You have
to use some judgment here, and manufacturers should specify whether the
component is OK for wash, and what kind (many components are OK for water wash,
but not certain solvents). If not, it's supposed to be soldered to the board
post-wash.

Good luck.
Chris

 

[Richard]

Your biggest "gotcha" will be whether all of the
parts on your board can handle the water.

Good point. That's easily handled, once aware of the issue.

Thanks to everyone for the comments!

 

[Walter Harley]

Many fluxes are corrosive (especially in the presence of any heat, either the
components themselves or self-heating of traces). A dishwasher is a good idea
for water-soluble fluxes.

Does one use detergent, or just plain old water?

 

[Vincent Himpe]

What are your favorite techniques for cleaning PCBs after assembly?
Especially for getting the flux residue from under surface-mount parts.

How far-fetched are the suggestions to use a dishwasher rinse / dry
cycle? Does this really work? Are there any drawbacks, if your flux is
water soluable? (Like, will I poison my dishware? ;-)


I've seen plenty of warnings that flux (especially fast-acting) is
corrosive enough to eat traces after a few months if not cleaned. I
normally use an RA flux pen that's "non-corrosive", but it still needs
cleanup. http://www.mgchemicals.com/products/835p.html

simply use low residue no clean flux. problem solved no cleaning required
as you don't see it. Kester has it

 

[Richard]

Does one use detergent, or just plain old water?

I'd expect without detergent, since the manual alternative is water and
toothbrush.

Dishwasher detergent is fairly harsh chemically, which is what makes
many things non-"dishwasher safe". If the flux is water soluable, there
should be plenty of heat, dilution, water flow, and time in the cycle to
do the job.

 

[Andrew Tweddle]

Does one use detergent, or just plain old water?

plain water, but be in a place where water quality is "good" as some
potable supplys are overloaded with chlorides, iron, copper etc, which
end up drying as residues which you then need to remove etc.
The water soluble fluxes often have enough surfactants in then to form
soap bubbles as high as 6 foot if you open the door in mid-cycle, did
this once!

regards Andrew