QFP soldering

What may be of help is to take a useless (broken) QFP of the same size/shape/pin-pitch, and lay it on the board, which I presume has no solder mask, and paint over the pins with clear nail polish. Once that's done, you blow on the stuff until it no longer flows, then remove the QFP before the nail polish dries. you then wait for the nail polish to dry. Once that's done, you put the desired QFP in place and apply solder flux, then, with a small, hot tip, solder the corner pins in place so the thing doesn't move around, and then go back and solder the remaining pins, applying solder as needed, but sparingly, and, after the whole thing's in place, put a solder wick on top of each row of contacts, and wick up the excess solder. It's not perfect, but it works pretty well and avoids those annoying solder bridges. Try to keep the temperature pretty low, but high enough that the solder flows readily. For that purpose, I'd use a narrow and fine-pointed tip that can easily fit on a single pin. It's no trouble geting more than one pin, but often it's necessary to hit just one, and that's what I'd try first. Don't do ANYTHING to the leads on the QFP! They're already tinned. A little liquid flux may help, if applied on top of the pins once theyre in place, though. I'm going to have to buy stronger reading glasses before the next time I do this. Dick ----- Original Message ----- From: "Cini, Richard" <RCini(a)congressfinancial.com> To: "'ClassCompList'" <classiccmp(a)classiccmp.org> Sent: Thursday, January 24, 2002 11:50 AM Subject: QFP soldering