I found many questions about how to perform reflow soldering, but my main concern is
- What are the consequences of not following the recommended reflow profile.
- Would there be any risk going the approach I plan to take.
So, I have a board about 9 inch^2 and a hot air gun and Kester solder paste. When doing my first assembly I noticed that if I got the lead partially melted and then slightly cooled down, it is more difficult to re-melt it again. Also, it takes a long time to heat the board with the hot air gun. I did not want to use oven, being afraid that I might overheat the components, whereas using a hot air gun would let me control local heating just to the melting temperature, simply by observing it. What I plan to do is to get a cheap oven at the store and preheat the board to say 180-200C. Then, use the hot air gun to finish the job.
I realize that the peak temperature must not exceed the maximum allowable temperature for components. I can easily ensure that. But how about the profile curve? The heating rates?
Regardless, whether using only the air gun, only the oven, or the combination of the two, I will definitely not be able to perform the task within 250 seconds as suggested by the profile. Neither, I will be able staying close to the suggested profile. So, again, what are my risks on not following the profile and is it worth combining the two techniques, or use exclusively one?