Hi, Wagner

> Peter, it is interesting.  I always tought to test the single temperature
> slope as your solution does.
>
> The recommended paste soldering says a dual temperature slope, increase
> temperature to a certain point, hold there during some time, then increase
> temperature to a second setpoint, hold for a short time and turn off
> everything, just keep the fan active to cool it down.  The first
> temperature slope is to heat everything, board, components, solder paste,
> and create a pre-solder environment, the second slope quickly melts the
> paste instantly, so, melting temperature is applied very briefly reducing
> the probable thermal damage to components.

    I use a small toaster oven for quite a while to produce boards and the
right temperature profile is essential if you want repeatability and
maintain good quality of the boards. I have made thousands of SMD boards
with this method and it works very well if you use a controller that can do
the right temperature "ramps". You also have to take care at the spacing
between the components if not using airflow.

    Without the right temperature profile maintened all the time the results
will not be repeatable and soldering will not be done right for different
board. You can get lucky and find an oven that has the right profile by it's
own size and thermical inertia but it is not probable.

    I though about making a temperature controller but buying a comercial
one was the cheapest and most reliable way to do it.

Best regards,
Alexandre Guimaraes

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