Solder for circuit boards

I use a rosin core solder - the core being the flux that helps solder flow. I also have a small can of paste flux that I use when soldering wire to the rails - put very little paste (i use a toothpick as the applicator) on the rail where you are going to solder.

But your main problem may be that you are heating the component lead, but not the copper pad associated with the hole. You need to get the soldering iron to touch both the lead and the pad at the same time so that they are both heated to get the solder to flow.

Clean the soldering iron tip, apply a very small amount of solder to the tip, then make contact to lead and pad, wait a sec for heat to transfer, apply solder. A clean tip, then with the very small amount of solder applied to the tip, help with the heat transfer from soldering to lead and pad.

Set it for the highest heat. The procedure is to “Get on and get off” quickly. If the solder is not flowing, the connection is not hot enough. Heat the pad and the pins together. Test by placing the solder on a pad or pin, NOT on the iron. The iron is always hot enough to melt the solder. You have to get the pins and pads hot enough to melt the solder.

The worst thing you can do is not use enough heat.

I'm going to have to disagree with you here Rich.  For PCB work, a really hot iron risks lifting the traces quite rapidly.  The iron should be in the 500F-550F range for small traces, maybe up to 600F for larger traces.  I've lost count of all the wrecked circuit boards I've see due to poor soldering and/or excessive heat.

I'm usually pretty good at soldering. MED - I've done all the things you've mentioned. I use flux, resin core solder and have a new clean tip. I will try making the tip a little hotter and touching the pad and pin per Rich Melvin but I was afraid of holding it on too long and ruining the board as GRJ mentioned. I know it's a fine line. That's why I was asking if there's a particular solder that's better for CB's.

I suggested the highest heat because he said the solder was not flowing. That’s a sign of not enough heat.

Even with a big iron, if you get on, heat the pieces, flow the solder, and get off fast, you can solder with a big iron on PCB boards. I’ve done it tens of thousands of times.

And you do not need flux!!! Just use good rosin core solder.

To all, I turned the soldering iron from 4 to 5 and just touched the connection for a second and the solder flowed great. It couldn't have been too much hotter but I guess it was just enough. Thanks for talking me through this, Don

I never have my irons lower than 650 no matter what the job is. Usually set to 700.  The key is speed and don’t press hard.  A few videos to watch.

this guy is great, my go to guy when I’m working on antique radios or vintage stereo equipment

After cooking more than one SMT part with 650F, I use 500F on SMT and if I'm doing larger thru-hole stuff that needs more heat, 600F.  If you're using 63/37 Rosin Core solder, 500F will solder any small part on a PCB unless it's a huge embedded ground layer you're soldering to.  YMMV, but I keep the heat a low as I can to still get reliable soldering.

If you're trying to use the lead-free solder, that's most likely where much of the solderability issues come in.

Superwarp1, Good videos. I should have thought of You tube- you can learn how to do anything there.