I've just made a PCB which uses a Mega8 AVR in the LQFP package. I don't tin
my boards, and usually solder the leads of that sort of chip one at a time
after fluxing the pads with a flux pen. This time I thought I'd try
drag-soldering, although I wasn't sure how well it would work without any
solder mask. Instead of the flux pen I used Warton Future HF Rework Jelly on
each row of leads after tacking down two opposite corners of the chip. With
a Metcal hoof tip (larger than the mini-hoof I use for fine-pitch devices) I
drag-soldered each row, and only had one bridge. The Rework Jelly is more
active than the flux in the pen, and I got very neat joints - much better
than I can achieve by soldering the leads one at a time.
Leon
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Leon Heller, G1HSM
Suzuki SV1000S motorcycle
leon.heller@...http://www.geocities.com/leon_heller