We're with Kevin.
First, there is hardly a worse cleaning solvent for fluxes than IPA. At the best, it will spread the soluble residue over a larger area, until it is thin enough to be invisible. This increases the surface area so that any dangerous contaminants, such as those ionic compounds that are soluble in IPA are more readily accessible to cause harm.
Next, IPA is VERY poor at dissolving the metal-organic salts formed by reaction between the flux and the oxides and will do so ONLY if it is virtually 100% pure => saturation occurs at ppm levels.
Remember, IPA is extremely flammable and its bulk use makes the plant liable to all sorts of quite repressive safety rules/regulations and so on. Ignoring these rules exposes the owner to fines and possible plant closure.
Using IPA for cleaning flux residues became popular because of: * Erroneous belief that what is used for formulating a liquid flux must be good for cleaning off the residues. * It improved cleaning capabilities of Freon and it was still on hand * Who knows?
... anyway, this forgets [ignores] that: * IPA can damage components and component marking. * SHeating to over 200�C modifies some flux constituents. * Chemical reactions occur during the fluxing process modify flux constituents.
Second, we too use nc wire solder for third ops soldering. Cleaning these nc flux residues is bad news. If the res can be cleaned at all, it requires a saponifier. Using a saponifier gets you into using an aqueous washer, which you don�t want to do with 3rd op components. You�re stuck.
Third, if your customer is not placated by chanting the �no benign residues of no-clean� mantra and this is a solid customer requirement, consider using a different flux in your wire solder that can be spot cleaned. Look at using a RMA and M.G. Chemicals [212-269-5533] "Safety Wash Cleaner Degreaser". We have no experience in this area. Check the fine SMTnet Archives for a contact of a SMTnetter [Genny] using Safety Wash to clean RMA. The thread is less than 6 months old.
Finally, using ultrasonic cleaners is not appropriate for some components. There is a thread on this in the fine SMTnet Archives. Continuing, usually people sink the board in a liquid when using ultrasonic cleaners. This gets you back to the not wanting to wash these components problem.
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