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Old 12-03-2014, 07:14 PM   #1361 (permalink)
cts_casemod
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Join Date: Nov 2012
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Quote:
Originally Posted by Astro View Post
I used to do the same.

When i used to use the soldering iron for SMD i would sometimes get the components preferring to stick to the tip of the soldering iron rather than the PCB pad.
Also it was difficult to remove components. Many times i found myself heating one end of a resistor then quickly trying to heat the other end before the first end cooled enough to solidify again.

Then, when i contemplated doing all my BMS cell top boards (lots of boards and lots of SMD components) i thought i would treat my self to the hot air station. Always looking for justification to buy more tools.
I should have done it years ago. The hot air makes it so easy, neat and clean.

On one of the first few boards i did i manage to solder the pic micro in reversed. Doh.
With just a soldering iron this would have been a pain to fix without risking heat damage to the micro and probably making a mess of the board. With the hot air wand it only took a few seconds to heat it, lift it, rotate it and re-place it. Couldn't even tell it had been reworked afterwards. From then on i was a huge fan of hot air soldering.

The solder paste is brilliant as well. Each pad gets just the right amount of solder.
The couple of times i did get a solder bridge between micro pins. All i did was reheat the area for a couple of seconds and boom solder bridge gone. The flux in the solder paste really works well. The solder runs to the pad and component leg as if it was magnetised.
Mesmerising to watch.

Also the solder paste holds the component perfectly. I can pick and place the entire board before soldering without fear that i will bump the PCB and have the components move around. It also means i don't have to keep swapping between soldering and pick and placing.
I firstly place all the components one after another on all the boards,then when i finish that i move on to the heat gun. So the first step is just using the tweezers and the second step is just using the heat gun.
I was picking and placing between 10 and 20 boards at a time. This made the process much quicker and also reduced error as i would place the same component on each of the boards in turn then select the next component and place it on each of the boards in turn.

When i do have to solder a through hole component the solder station has a nice temperature controlled soldering iron as well.

It was $70 well spent.
I second that. Hot Air serves as a dual purpose to remove or re-work only some components. And one doesn't risk overheating a component for too much time or wife complaining about our cooking in the oven

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