Homebrew PCBs

Eeks Sdfgvbsdfgggggggg <eeks123@...> writes:

> is it easier/cheapier to solder with a hot air gun or with a
> modified cheap oven?

I use a hotplate for most of my smt, and a 0.020" conical tip iron for
the rest.  http://www.delorie.com/pcb/hotplate/

More near the bottom of: http://geda.seul.org/projects/djs_pcbs/

> if you have SSOP and that kind of small ic's you have to use
> soldermask to avoid a big soldermess don't you?

Nope.  I've done down to 0.5mm pitch parts with no mask.  In fact, at
those small sizes, the average proto fab can't put mask between pads
anyway, and the solder would just bridge those tiny mask strips
anyway.

You may need a mask if you have other traces between those pins,
though, if you find you're getting bridges to those.  Only because
it's harder to get the braid down there to clean them up.

> do you buy solderpaste in any electronic component store or do you
> have to buy it online in a US store like digikey? (i'm in europe and
> the problem with soldermask is you have to keep it cool)

I got some SynTECH paste online.  It doesn't need to be kept cool.  My
one syringe of it has been in use for over a year and still seems fine
to me.  Unfortunately, the place I got it from doesn't offer it any
more.

> are there any hints for a SMD-newbie or typical errors you do when
> starting?

What I like to do is dab a little solder paste on the pads (manually,
with the syringe), place the part on the paste, and use the iron to
heat the copper until the paste melts.

For the really small parts, the wire solder is "big" enough that
surface tension tends to pull on the part.

For hand-soldering chips, my philosophy has become "put more than
enough on, then take off the extra".  Don't skimp on the solder at
first; it's faster to be slightly excessive than to go back and try
again on cold joints.  If you create a bridge, they're easy enough to
remove with some copper braid.