This sounds like a good approach especially for the beginner/novice.I have a TV that suffers a bad solder joint due to heat expansion and cold contraction. I have to wait about 5 minutes typically for the joint to make a good enough connection to make a clear picture. Meanwhile I have the upper left corner somewhat doubled and scrambled.
Not specifically, but just a rule I go by. No closer than 2mm. As the afore quote and reply states, expansion and contraction can play havoc with solder joints.
Quite likely too long and probably too hot. But - - -
Certainly it shouldn't take that long. But there are many factors that come into play when soldering and timing of heat application. For the average hobbiest, half a second with tin lead and an iron somewhere around 450˚F (just my preference, not a rule) (other opinions may vary), 450˚F should be sufficient. All it takes is enough time to transfer heat to the joint and for solder to flow and bond. It's called "Wetting". Wetting is like how the water in your glass sweeps up at the edges. It's the tension that pulls the water up the side of the glass just a little. When you solder, you take a small amount of molten solder (a tinned iron) to the joint. Give it about half a second (don't go timing your application because some boards may have ground or power planes that draw heat away, and longer time and often hotter irons are needed to complete the solder operation). At the half way point you add additional solder, just enough to fill the through hole and wet to the lead and pad of the joint. Once the solder has become molten and wetted the lead and pad - get the heat out of there. Don't let the lead move. Disturbed solder while it is freezing (yes, freezing. Solder freezes at high temperatures) Disturbing the solder while it is freezing makes it look grey and grainy. It's a poor joint because the molecules have been disturbed. If you get a joint that looks that way, apply a little flux and reheat the joint long enough to transfer heat fully into the solder joint. Shouldn't take more than a second. Again, different boards and conditions change everything. I've found it difficult to solder outdoors. Impossible in the winter time, the joint cools too fast for the heat to permeate the joint and flow the solder. I've even soldered on boards that had to be "Pre-Heated" before soldering simply because there was so much material to draw heat way from the joint. But I don't think you're working on anything like that. If you make a career of it then it's quite possible you'll come across that situation.
best way to hold LED in place before soldering
- Thread starter clangray
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