Hi Fritz, i'm still learning here and that is
one thing i'm playing with. It depends on the
distance the boards are placed above the elements,
and how many boards are in there. And obviously
the element power.

Currently I have the boards about 25mm above the
element, it goes like this:

* preheat oven to 150'C
* insert boards, preheat for 2 to 3 minutes
* turn oven up full (check stopwatch)
* takes about 35 seconds for solder paste to melt
* give it about 15 seconds after that
* open door and gently slide rack out

The results are reasonably good, but more importantly
they are predictable each time. On the 28pin PIC
there were maybe 2 legs dry and 2 legs bridged, I
found by increasing the solder paste amount I now
get no drys and maybe 2 or 3 bridged. All of the
joints are excellent (I use 30x microscope) and
removing a couple of bridges per board takes a
few seconds manually with an iron and wick.

It's good enough for small production now, and
as I refine it it's getting better. I use a 19 gauge
needle on the paste syringe, ground flat and only
10mm of needle length. I just need to practice
laying down the correct amount of paste, each run
it gets easier.

I welcome any suggestions, and as usual I will
probably end up putting my procedure and pictures
on my web page. :o)
-Roman


Fritz Braun Jr. wrote:
>
> How long do you cook it at full temp?
>
> ----- Original Message -----
> From: "Roman Black" <fastvid@EZY.NET.AU>

> > Hi David, I didn't see the group but had checked
> > out a couple of amatuer SMT pages on the web.
> >
> > You really don't need a special controller, I
> > just preheat the oven to about 150'C, put the
> > boards in, wait 2 minutes, then turn the oven up
> > full and watch the stopwatch. Works every time,
> > just takes a little practice getting the boards
> > placed well over the elements for even heating.
> >
> > I can take a picture and post it up if you like.
> >:o)
> > -Roman
> >
> >
> > David Harris wrote:
> > >
> > > Hi-
> > > Are you aware of the Easy-Bake egroup at
> > > http://au.egroups.com/group/E-Z_Bake ?  Kind of quite now, but plans
> were
> > > to dedign a controller with temperature control to do this.  Do you have
> > > any pictures of the results?
> > > David
> > >
> > > Roman Black wrote:
> > >
> > > > Hi Guys, we have successfully done a few boards
> > > > now with SMT PIC chips in a cheap toaster oven,
> > > > they are coming out quite good.
> > > >
> > > > Many thanks to Alexandre who sent me a temperature
> > > > vs time chart, and helpful "expert" tips.
> > > >
> > > > Just letting you know you can get a pretty good
> > > > result with a $35 US (second hand) toaster oven
> > > > and a stopwatch, and good solder paste of course.
> > > >
> > > > Each run it seems to be getting a bit better.

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