Hi ya'll!

I'm getting ready to do some intrusive reflow on this board we got
here...(this is my first time! I'm s-o-o-o nervous...not really...well, maybe
a little...hehehe) Anyways,
the parts are going to be 2, 20-pin SIP sockets. The board is .063" thick,
the holes
are spaced .100" apart, and the hole diameter is .040". I'm trying to decide
how big I should make my apertures.

I've looked at all the archive postings (there are a 168 of them on intrusive
reflow) to see if anybody posted any recommended stencil thicknesses, and/or
aperture sizes,
but there was none. I looked on the web, but couldn't find any real
guidelines either...
(hmmmm, something I couldn't find...now THAT's a change!)

I need to keep my stencil thickness at 6-mils, 'cause I've got some 20-mil
pitch stuff on the same side. I was thinking of doing .060-.070" diameter
circles over the holes...
does that sound okie-dokie?

I did a little test with the SIP socket and a syringe full of solder paste. I
drew a bead of paste (about .030" dia.) down the row of holes and dropped the
connector in, then reflowed it. Then I got my dremel tool out and did me a
rough cross section to check the barrel fill. It actually wasn't too
bad...there were about 2-3 holes that were a little shy volume-wise but that
was because (I think) the solder wicked over to the holes next to it because
of the continuous bead of paste I had laid down. That shoudn't happen when I
have individual deposits of paste for each hole.

So how big should I make my openings? Did I guess right at .060-.070"?

-Steve Gregory-

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