I crank it up if I am doing large tabs and wire. For components depending on what it is 650-750.

I solder at 620F but my iron has faster heat recovery than most.

Weller suggests a range of 700F-800F. Most joints should flow within about 2-3 seconds (heavy power or ground traces take longer). Run at the lowest temperature that can accomplish this.

With wires, if you see smoke coming from the insulation or nearby plastic parts you're too hot. If the insulation softens or melts a little that's pretty normal for heavier wire such as you'll find in pinball machines.

Weller's "Better Soldering" booklet:
http://www.apexhandtools.com/weller/PDFs/betterSoldering.pdf

Weller's 10 Commandments of Soldering:
http://www.apexhandtools.com/weller/ten_command.cfm

i got a Weller WES51. i crank it between 750-800 for almost everything. bridges i do at 850. works perfectly. great iron.

In general you should start lower as rancegt suggests, esp when dealing with older boards where the only thing holding the pads on are the solder itself.

viperrwk

I have a controlled Weller as well. I use about 670 for most board pads, about 700 for larger current ones/grounds, and maybe 730 for very large grounds.

Lugs I'm about 700-750.

I would recommend reading pinrepairs summary on tools and soldering. Very informative.
http://www.pinrepair.com/begin/index.htm

I keep mine at about 650 for most repairs. For board repairs I lower it to 550. Keep in mind that lead free solder has a higher melting point (about 100 degrees higher) than leaded solder.

It's not a good idea to mix lead-free and lead solder. You can create some pretty serious reliability problems. Therefore, I would suggest you never use lead-free solder on a pinball machine. The exception would be a modern game that's manufactured with lead-free solder. Does anyone know about that?

Also, pinball PCB's are fragile to begin with, and running at the higher temperatures required for lead-free is likely to be harmful in itself.

650-700 depending on situation... but i suck at soldering so dont take my word on any of this

I have used my radioshack soldering iron on the boards and under the playfield without issue..

I always set it to "just melts a line of solder", then nudge it just a little so I'm not holding the heat too long in one spot. I too have a weller, and usually set it to 700°F

The proper temperature is the temperature that allows you to work quickly without overheating a component. This will vary greatly depending on the size of the item you are soldering relative to the size of the tip on the wand. For most general electronics this is probably in the 600-800° range but that's only a starting point. Its important to keep in mind the relative size of the parts you're soldering. For example, a giant flat chiseled tip will transfer a heck of a lot more heat to a resistor lead then a tiny little conical tip will, so turn your iron down so you don't lift traces, which you might do anyway with a setup like that, even at 600°. On the other hand, a tiny little conical will probably struggle to melt the solder on a heavy lug or ground plane without cranking the iron way up, at which point you might start causing some lift or just roach out your tip by overheating it. Lots of people will tell you they've never had a problem but I prefer not to bring luck into the equation and take the chance at ruining or damaging an expensive piece of equipment.

Also, don't forget to use an appropriately sized tip. Larger blade variety for coil lugs, smaller tip for transistors and IC legs, etc.

... and use a soldering heat sink where needed.

This is not completly true and there is hardly any evidence that mixing the two will create weak joints. The theoretical arguement behind this is that the joint is seen as weak because the lead free soldier hasn't fully melted to the point of the leaded solder causing microscopic indifferences in the mixed joint. Since everyone here has their heart set on a soldering temperature range of 600-750 this should not pose an issue, if it is an issue at all, since both types of solder should be fully melted. If you have any good references or documentation I would love to take a look at it.