At 14:49 -0700 10/23/09, James Fraser wrote:
>Hello,
>
>--- On Fri, 10/23/09, Doug McNutt <[email protected]> wrote:
>
>> Most soaps are not good for circuit boards. During
>> manufacture boards are exposed to soldering temperature of a
>> little less than 200 C and they are also washed with water
>> to remove soldering flux. 
>
>When you say "washed with water," do you mean distilled water?  Or ordinary 
>tap water?
>
>I ask because I've heard it claimed that regular tap water can leave behind a 
>residue that isn't good for electronics.  But I've never actually chased this 
>up to see if it was true or not.

The operations I have actually seen used plain old tap water but here in 
Colorado Springs that means treated surface water which is really not so high 
in dissolved minerals. Good old ocean salt would be a terrible residue to 
leave. Any humidity in the local atmosphere would make NaCl into a conductor.

A distilled water rinse, before the washer water is dry would be wise. Melted 
ice from a refrigerator defrosting operation is pretty much mineral free. A 
good shake while still wet from rinsing in the washer is probably good enough 
for Apple work.

Personally I like to dry boards by spraying them with dry isopropyl alcohol 
from a local commercial cleaning company. About $2 per gallon and it's 
water-free. But I also use rosin core solder and the alcohol is much better 
than water for that.

Real pros go for deionized water which is a step further than distilled water 
because the H3O+ ions are suppressed. It's corrosive and has to be removed 
quickly. Don't even think about it.
-- 

--> A fair tax is one that you pay but I don't <--

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