WS609 is a wonderful paste.
J-STD-001, 4.2 states words to the effect that for Class 3 products Type H or M fluxes should only be used for tinning operatins. Most water soluable fluxes are either H or M.
I believe that you can use Type H or M fluxes in Class 3 products if you qualify the flux with the product. From the sound of things you might have a difficult time getting your customer to accept the results of the qualification.
This appears to be one of those times when the customer is correct. Sounds like you should cancel that order with Trek, eh?
Dr. Ning-Cheng Lee at Indium hosted an On-Board Forum here at SMTnet.com.
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