I get impatient so I put a timer, and I start with the wide nozzle 3-4 cm away, making wide circles around the part for about 30-40 seconds. If you need to use a heat gun, I would recommend you try some experiments on a test board before trying to remove the "important chip". But of course, you can't use them to remove a chip. Most commercial ovens have decent temperature probes as well, so in general, they work better for a new board. Ovens are a bit simpler - since the entire board is enclosed, it gets uniformly heated and the rate of temperature increase is such to ensure that the entire board follows along, without cold/hot spots. There are probably other issues I'm forgetting but you can see, there is a lot going on. You can use a "hotbed" but that's hard to do if a board is built and contains through-hole parts. The recommended approach is to spend a bit of time blowing hot air over the entire board, or at least a wide area around the chip you are trying to remove (the soaking phase) however, if the board has thick copper planes, it can be really hard to warm a spot as the board acts as a heat sink pulling the heat away. The design of the board matters a lot.So higher airflow ensures there is less time for the air to cool down, but it may blow a chip or neighbouring parts away so there is a tradeoff. The airflow matters once the air it's out of the nozzle, it cools down due to the ambient temperature being much lower. ![]() Even if the air temperature is at 250, that is usually at the point of measurement, usually somewhere near the output nozzle, however, the distance at which you hold the nozzle away from the chip can drastically change the temperature that the chip "feels".To start, you are not certain that your hot air station is calibrated properly, so it may say 250 but it may be off by any percentage. Temperatures when using hot air are a bit tricky.
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