Soldering help needed, PCB holes are plasticising

[ungleichklang]

Hi folks,

first of all, sorry for my english ....

I did a couple of PCB's before, about 20, so it doesn't make me a pro ... but, atm.
I'm soldering the "El Cerrito" PCB from magic smoke and on some (about 6) drillingholes I couldn't get the lead to the PCB, so I looked at the holes and saw, that a fine film of plastic/resin has melted between the resistors-legs and the hole, I tried to scratch of this shi** but can't get those points to solder in correct. I rried to resolder, but this resin has now flowed all over the resistor legs and the holes on both sides of the PCB, so that I can not get those points to connect.

I don't know if my iron was too hot or what else has happened ... but now it seems too late ..
I used 310 Degree Celsius, a 1mm tip and ~3seconds per solderingpoint ...

Can someone give me a tip or name a product that does break up this plasticine-thing ..

Thanks in advance ..

[Abby Normal]

Hello,
It sounds like you are doing everything correctly. The resin that you are seeing is probably the cleaning agent (flux) that is inside the solder. It is supposed to melt along with the melting solder so it can clean the items to be soldered for a better connection. After soldering, it helps to clean the area with isopropyl alcohol (try 90% isopropyl), or a flux cleaner.

What type of solder are you using? There are different types. Hopefully you're using a rosin core solder, or something similar that is intended for electronics.

As you add heat to the connection to be made, try adding a small dab of solder where the iron contacts the parts and board. Wait for about a second or two, and then add additional solder to finish the job. You want just enough solder to completely flow through and cover the connection of part lead to the PCB mounting hole. Here's an example of what it should look like:

http://www.antex.co.uk/images/betterfig5.jpg

[ungleichklang]

Thanks Abby Normal,

my lead is normal solder-lead SN60PB40 in 1mm thickness

[Abby Normal]

Here's a helpful soldering video tutorial:

http://www.youtube.com/watch?v=I_NU2ruzyc4

A chisel tip for your iron might help. The video shows the different tip shapes at the end of the video. Check out the whole video, though. There are very important and helpful tips throughout.

A key thing to keep in mind is that the PCB solder pads, and all part leads have to be clean and free of oxidation to solder well. Is your PCB very old? Maybe the pads are slightly oxidized, making soldering difficult. The video explains what to do in this case.

Each point to be soldered should only take 2-3 seconds to complete the job. If you go beyond 5 seconds, it's probably best to remove the solder, clean the joint of the old flux, and re-solder it again.

[emdot_ambient]

I just saw two others on muffwiggler's forum yesterday talking about the same thing happening on different boards from the same manufacturer.

The general consensus was that the pads causing the issue are connected to large grounding planes and, with the boards being thicker than a lot of other manufacturers' to begin with, the grounding plane is acting as a heat sink.

Recommendations were to use a chisel tip using the flat of the chisel on the pad, wet the solder tip with solder before working, and to use the iron on the pad a bit longer than normal, possibly at a touch higher temp. Don't push hard on the pad and only solder less than 10 seconds continuously to prevent heat damage the board.

[ungleichklang]

Now that is a good hint embot_ambient .. got the alcohol to clean everything today, will add SK10 before soldering and change the tip .... we will see what happens ...

I will be on a Synth-meeting (Dinosauriertreffen Bocholt) this weekend and will take the board with me if it does not work like above ...