Solder won't flow nicely on some PCBs

[giovanni]

I recently bought lead free solder and I noticed a significant difference. Leaded is much easier to use. I use a Pace set at 700F and I never had issues. The unleaded stuff sometimes looks like it’s not flowing but then the resulting joint looks fine so I don’t know what to make of that!

 

[falco_femoralis]

Solder flow issues are almost always due to a lack of heat. If you're using lead free solder start with your iron at around 350C and go up from there maybe to around 450 if the solder doesn't melt within one second of touching to the iron and components.

Also a thicker tip transfers heat better, maybe try a 2mm

 

[bechbox]

It's odd though, because it looks like some of the other ground pads didn't have that same issue.

I've had the same issue when I soldere 3 or more of the same board (can't remember which ones right now) - the exact same through hole on every board was nearly impossible to solder, so it's not because of issues with the iron, solder or temperature like others suggest.

 

[Matopotato]

I've had the same issue when I soldere 3 or more of the same board (can't remember which ones right now) - the exact same through hole on every board was nearly impossible to solder, so it's not because of issues with the iron, solder or temperature like others suggest.

Thanks,
How did you manage in the end, or what did you do?
Mine look a bit dodgy, but before I cut a leg/pin (not on solder or pad) I use connectivity buzzer to see if the leg reaches next points in the schematic.
Not sure if this is proof of a working/good even, solder point, but I hope it counts for something. (Bridges are of course not found this way...)

 

[jwin615]

I've had the same issue when I soldere 3 or more of the same board (can't remember which ones right now) - the exact same through hole on every board was nearly impossible to solder, so it's not because of issues with the iron, solder or temperature like others suggest.

This sounds like ground plane heat absorbtion