[Diy_efi] PCB washing using water

[Bill Washington]

Mike,
	I beg to differ on PCB washing, for the last 10 years or so in PCB assembly the 
fluxes used are water soluble and the PCB wash after assembly is with water to 
remove whatever residue remains after the reflow process - most of the flux 
evaporates in the reflow oven which peaks at about 215 Deg C for a few seconds. 
This change was essentially brought about for environmental reasons.
	Therefore washing the pcb with water without power applied is safe because tha 
components are designed to cope with this, and as someone else stated natural 
drying is preferred to compressed air because oif the static issue.
	However, that being said, the coolant residues may require a subsequent wash 
with isopropanol to complete the cleaning - CRC also produce a product called 
'Contact Cleaner' which I have used sucessfully on occassion.

	As an aside, there is a rather large change happening now in the electronics 
industry with the migration away from components and solders containing lead and 
a number of other substances which are considered 'hazardous'. This is referred 
to as RoHS (Removal of Hazardous Substances) of which "Lead Free" or "Pb-Free" 
is a part.
	This becomes mandatory in most countries during 2006 and has been a big 
challenge (and expense) for the industry.

	One effect of this is that the melting temperatures of Lead-Free solders will 
be higher, and Lead Free solders do not flow as well as solders containing lead, 
therefore the joints will look 'different' and 'dry' joints will be much more 
difficult to identify visually.....

Regards
Bill