Best Solder

Dear Marakanetz,
Are you in agreement that the solder should be touched to the heated trace and lead and not to the tip of the iron?

If so, then I would need to either turn up the heat or use a solder with a lower melting point to shorten the two or three seconds after I touch the solder to the lead and the trace?

Right now, I touch the tip of the iron to the lead and trace together for about 3 seconds before touching the solder to the other side.

my experience has yielded good results by touching the solder to the iron-trace junction, so that some solder gets on each. Helps to speed up the initial melt at a somewhat lower junction temperature (causes less stress on the component) yet still flows well across the conducting surfaces being soldered

Jj it's just strictly technique issue.
Whenever you feel that conducting leads are ready to be joined, pour the solder onto them.

It must be a nice shiny "hut" but not blob or bubble...

I'm posting again since somehow this didn't go through....

So my following comments will complement some of the above notes.

Some silver containing solders require higher temperatures to melt. This can be an inconvenience specially working on printed circuits or surface mounted. There is a risk of overheating deformation or desoldering adjacent parts. In the case of cable and interconnects there can be oxidation and insulation damage.
I prefer to work with eutectic low melting point solder and do a good physical bonding (eg wire metal) between the conductors and then secure it with the solder. Cleanliness and good preparation of parts to be soldered is needed for a quality job.

Working with lead solder requires common sense : wash your hands properly after using it. Better yet use protective latex gloves ultra cheap and safe. This material to affect you has to be inside your body, in other words it doesn't jump at you and kills you. The normal hygiene practices are enough to work with the material properly.

Eutectic solder has a single temperature for melting and not a range. A non eutectic one behaves as follows: part of it starts to melt earlier and others after, likewise to solidify the same happens but in reverse order so it's slower to work and maintains more stress upon solidification that later might yield a broken soldedered part. Eutectic provides in my experience better and more important more reproducible results.
The use of a variable power soldering instrument is desirable to avoid working with too hot an iron and this way lessen damage chance.

Eutectic Sn/PB 63/37 melts at 361 F.

WBT types : Sn/Pb/Ag 62/36/2 melting range 354-372 F

One key point to remember solder has to melt, wet properly and after that solidify with the minimum stress. This requires a couple of overlooked things
1- Heat just enough and with power/soldering tip acording to size of parts to be soldered. i.e. larger pieces require more wattage iron and larger tip.

2- If you overheat the solder will "dance" over the overheated parts and not settle.

3- To avoid stress avoid sudden cooling by blowing air directly to the recently applied solder. That doesn't allow enough time for proper wetting/distribution of material.

4- Use rosin based flux not acid flux containing solders.

Hope this is helpful and not confusing

Luis

Q: Does solder smoke contain lead?