Homebrew PCBs

I routinely do qfn and 0603 parts using homemade stencils and a toaster oven that has been converted to a reflow oven. I make the stencils by drilling holes in thin fr4 with a cnc router over the pads - .012 holes for qfn and .026 for most other parts. After applying the paste I put the board in a fixture and drop another piece of fr4 that has cutouts for parts placement over it. I then just drop the parts into their places and pop it in the toaster. Works fine for me. Downside is that you need a cnc router to do it right.

Mark

-----Original Message-----
>From: DJ Delorie <dj@...>
>Sent: Jul 26, 2009 11:16 AM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: Re: [Homebrew_PCBs] making surface mount boards
>
>
>Henry Liu <henryjliu@...> writes:
>> I was thinking about this and can't I just pre solder all the SMT tabs
>> then apply flux and the part on it then bake it or use a skillet?
>
>I don't think it will be sticky enough to hold all the parts in place
>as you move the board around.  Once you've soldered the pads, you have
>a hard bump that wants to move the part *away* from alignment, whereas
>solder paste can be flattened and is sticky to hold the parts in
>place.
>
>
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