Hopefully the info I have given you helps.

Yes when I refer to my tip having gone bad (or being dead) I mean that it’s useless in the sense that solder won’t melt anymore and it won’t adhere to the tip as it normally does. 

According to the station display it is reaching the right temperature of 375C, but when I touch the rosin filled solder it doesn’t turn into a nice melted bubble of solder it causes the solder to break into a piece that falls to the table (in non melted form). 

Tip tinner LINK

Liquid flux LINK

Squeeze bottle & hollow tip LINK

Ultra thin solder for fine work LINK

Solder for heavier connections LINK

Here are some of the tips I ordered, I think the D16 is my normal tip LINK

Those tips fit this iron LINK

The two tips here are the special tips for dragging, with correct liquid solder and heat it does a very nest job LINK

I rarely use it now, but this is what solder paste looks like, consistency of peanut butter LINK

If you get into surface mount or just want to know more about soldering, then look up the website of LINK

His website is a mess, but that is where I learned what soldering station and hot air station to get. I also ordered the flux, solder in flux, and paste all in injectors that are NOT counterfeit from him.

Thanks a lot for giving me your oppinion on what tip model to use for this type of PCB job. 

I had tried to interpret the right size from soldering videos and articles, but I had obviously misinterpreated as I have been BL and BC1 tips, which are smaller than what you suggest.

I have ordered the ones you suggested to check them out.  Fingers crossed!

Paul

Yes that is the cradle I referred to.

I don't know how a tip can 'go bad' can you explain a bit more, does the tip get hot, does it melt the solder. I think you said the melted solder does not adhere to the tip, is that correct?

Regarding the Tip Tinner; is it normal for the Tip Tinner Powder to cristalize and get hard after touching the iron?  Do I need to throw away the the hardened (cristalized) Tip Tinner, or do you keep on using it?

I did not have solder paste in my kit, so I have ordered the one shown below. Is that the type of solder paste you were referring to?

As to the cleaning the tip with the steel / bronze wool every time it goes in or out of the cradle, I am using the one that came with the solder station, which you can see below. Is that what you meant?

Thanks again for your tips and I look forward to your reply

Paul

As I type this I just remembered that when I was soldering those two last joints the temperature display did jump at some point to over 400C just for a little while; which I found strange as it hadn't happened before.  

It uses the standard length T-12 irons that I posted earlier.  They basically slide into the handle leaving only a portion exposed. 

 I also have a Fnirsi digital smart pen like the one shown below that uses shorter T-12 irons, but I haven't started using that one yet as the tips are more expensive (so I want to make sure I know what I am doing before I risk damaging that one).

 Yes, I need to learn how to clean the PCB board after soldering.  The interesting thing is that it was fairly clean until the moment when I began trying to 'fix' some of the joints that I didn't think were good enough.

I had a few solder dots that were too close together and I was afraid that they might be touching each other.  So I tried using solder wick to remove the solder, but I couldn't get it to get hot enough like I see in the youtube videos.  Based on the posts in this thread, I believe it was most likely because of the small tip I was using.   So I had to leave the tip on it for a long long time before it started to absorb some of the solder and then it got stuck to the board, etc.   So I started using flux, but since I only had that solid one I soaked the tip into it and tried to move some of the liquid to the board; but obviously it got hard on the board when it cooled off.

To remove the solidified flux after I had finished I remembered seeing that alcohol was used in youtube videos; but there was so much of that solid flux that the alcohol just didn't get rid of it all.   As mentioned earlier, that is not the right type of flux for spreading on the board.   My recent readings on it suggest that it is only for the purposes of coating the tip to enhance the soldering process, but not meant to be used on the board itself as a liquid.

As to the wire guage size, I have no idea. Its the wires that came with the kit and they are slightly thinner than the ones used on arduino boards.  So pretty thin.   

Thanks again for sharing.

Paul

Having gone through what you’re going through I thought that I’d chime in.  Sharing is Caring, right?

I echo what @codecage said about the picture looking like cold solder joints.  I’ve found that a lot of PCB designers use copper zones to tie grounds and power connections together, something about having lower impedance than traces.  This is great for the board but a pain for us because the area that the soldering iron heats up is now very large.  As an aside, I noticed that soldering headers to the GND pins of the RPi Pico never gave me any problems, but the Pico-W takes more time and heat to get the job done.

Did you determine what gauge wire you are using for those connections?

Those tips look huge, what soldering station are you using?  In my case I’m using an inexpensive 30 Watt pencil iron with no temperature read out.  It’s taken some trial and error to find the right settings.  For through hole components and header pins I use a 1/32” semi-chisel tip with 0.025” rosen core solder.  I started with leaded solder as it is supposedly easier to use…  Recently I started soldering SMD components and for that I use a 1/64” conical tip and 0.3mm lead-free solder.

I recently ruined a soldering tip so that it no longer holds solder :/  It was a non-OEM tip, the only one I could find on-line, and I must have gotten it too hot.  I was tinning it constantly so that wasn’t it.  Luckily I bought two at the time so I’m using the second one but the temperature is not ideal (cold joints on GND connections).  I need to upgrade my kit!

That block of rosen reminds me of High School metal shop where we soldered together small boxes made from sheet metal.  Those soldering irons where huge.  As you progress you might want to pick up some flux, either liquid or paste.  To clean up that mess on your board you can get some solder wick, soak it with flux and use your iron to melt it into the wick.

I would not recommend drag soldering.   Check out MrSolderFix on YouTube when you get around to making your own PCBs and want to solder ICs.

The cold joints need more time under the soldering iron and possibly more heat.  If it were me I’d probably try soldering the same gauge wire to some scrape proto-board to make sure I haven’t set the iron too hot… Excelsior.

Tom

If I am going to do a lot of soldering, I will immerse the tip in the paste and rotate it to get full coverage and then clean it in the steel wool. Now a small application of Tip Tinner again rotate the tip to get full coverage. After that as I said, every time the iron goes in or out of the cradle, stick it in the steel/bronze wool.

If soldering every day, maybe once a week do the tip cleaning again.

I would use D24 or maybe D16, it's a litt. Larger to the left, and smaller to the right.

Also, if you know how to do drag soldering on say a IC, then the tips BC2 and BCF2 (finer) if hollow (or cows foot) will hold a blob of solder that you then drag apply across a row of pins/tabs etc. Lay down some liquid solder first and it just flies on. Great for headers on MCUs etc.