Best Solder

In reality the silver content in the solder or the absence of lead doesn't make it best.

The best solder should be the best for its particular application.

If you're about to build-up a solid state equipment(or work with OpAmps or ICs) than the temperature applied to the device leads is crucial. Therefore it's not desirable to have a solder that has high temperature of melting such as tin-silver solder. Any solder has very poor conductivity compared to the cooper or silver therefore its function is to hold conducting leads together tight. A content of silver in the solder only makes it to melt under the higher temperature and so higher power device should be used to work with such.

A lead-free solder has an advantage not to be as harmfull for the human flora over the one that contains lead. Despite that any soldering job should be done with good air circulation and avoiding inhalation of the flux and solder smoke.

The "speed" is the most important factor that I value in solder. The faster I join conducting leads the less I inflict them under the high temperature the less I stress the conducting material and device I work with. Becides the above mentioned speed I also love the ability to leak. Hard tin-silver ones can't do that and can form bubbles if not sufficient time applied to melt it. Therefore I figured that spending 5x or more for Cardas or Johnson ain't worth it(too damn "slow") and chose Weller.

P.S. Always remember to join conducting leads and NOT solder to solder!

Jj, You're definitely on the right track but the fastest melting solder consists only from lead wich has following important disdvantage:
The melting temperature is too low which means you can't use it in the power circuitry (or output tubes or transistors) affected by the heat. If heat acts on pure lead solder it will crack within the time to form a cold joint or lost of the contact.
Therefore pure lead or high content of lead solder should be used for small signal ICs that demand a very short duration of applied high temperature.

The mixture of tin lead and silver depending on quantity melts under different temperatures. Therefore it's a good practice to have at least two different kinds of solder.

You have to make shure that the power of the soldering iron is upto your application. For high-temperature solving solder you'll need higher power iron but than you'll have to make sure that you won't damage a circuit element.

2...3 seconds to melt is too slow. In my case the solder melts almost instantly and than leaks arround the soldering surfaces. This way you won't get any cold joint or bubble.

In this case I guess you'll need a more powerfull iron or different solder. For electronics applications you'll need the thin wire of solder

Having a soldering iron with variable power and number of different iron tips would help you match for a specific joint you will want to perform. Please also note that you should clean the iron tip freequently otherwise the heat transfer won't be efficient.

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...

No it doesn't but the flux smoke is toxic so proper ventillation is required.