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Old January 9, 2012, 04:30 PM
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Rison Rison is offline
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Join Date: Sep 2009
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well, if you're talking about gear.. weller is probably the best DIY iron out there. They have variable heat stations for $120-$150 range, and you can buy finer tips. If you go for a static solder iron, you're looking in the 25-30 watt range. Make sure you clean the tip + prep areas prior to, and after soldering. Cleaning is the key for a proper solder. Isopropal Alcohol / Isopropanol (99.99% technical grade) + lint free cotton cloth is your friend. It removes the flux after the solder so it doesn't eat away at the tin/lead over time. Most places carry the little brushes to get into the joints properly.
There's lots of stuff you can read online, like using the (often yellow) sponge to shock the tip (to bring heat to it instantly) before applying heat to the weld.. the little sponge isn't for cleaning the tip, like most people think / use it for.
The trick is the solder, you want 67/37 eutetic solder. This leaves a very low elastic point so it doesn't take long for it to set after removing the iron.. very important with fine work if you're using an iron instead of air gun. Most electronic places carry the standard thicknesses, and can order in the finer stuff for some of the resistors you're talking about. Most of the time, the issue is the angle of the soldering iron, and not the actual soldering itself.. trying not to hit everything around it on those tiny boards. That's where hot air is awesome - you can direct it rather easily with little error around the solder itself.
For soldering extremely tiny resistors, it's best to heat the pad with the iron (on the circuit board), then set the resistor on it.. and draw the solder from the resistor to the pad (solder always flows to the heat). This all happens in less than two seconds or you burn the pad/resistor up.. it takes a lot of practice.

There are probably a tonne of online resources, and some books available on methods and soforth.. some good, some bad. Any questions just shoot.
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