Hi,

I'm quite proficient at soldering and usually end up with a very neat finish. However, I now need to solder 10 boards which each have 2 sets of double row 70 pin stacking headers (140 pins per board in total). I would like a neat and professional finish and on my first attempt I found I could not get uniform solder joints and on some pins the solder ran up the pins, as you solder these on the pin side...

I'm wondering how to get a neat finish? How would these be soldered at the factory?

I have a good solder station and a hot air station, so if anyone could recommend a method that would be great?

Here is a low quality picture of my first attempt:


good image hosting site

Thanks,
James

 

You can't use the ones that have insulation separators?
https://www.digikey.ca/product-detail/en/omron-electronics-inc-emc-div/XG8T-1431/OR1103-ND/1829460
Max.

 

Thanks for your reply, I can on my second batch of boards, but for these 10 I only ordered a single layer board which means I have no solder pads on the top to solder onto. I'm basically trying to find a way to save throwing them away...

 

These would not be a problem if:

You use very little solder

Your solder should be thin, 0.031" max. Thinner if available. Rosin core for sure.

The iron tip needs to be very clean and freshly tinned. Cleaning for every joint is not excessive.

The board is very clean. IPA wipe-down if pre-tinned is fine, but may need a steel wool scrub if bare copper. Get every splinter out of you do use wool.

A small bit of flux may be necessary, but generally that in the solder itself is sufficient.

 

Thanks , it is very nice of you

 

I have a good solder station and a hot air station, so if anyone could recommend a method that would be great?

Through hole parts are best soldered with a soldering iron.

The picture is blurry, but I think better technique would yield better results. Heat the lead and pad and apply only enough solder to get sufficient wetting.

If solder is going "up" the leads, you're applying solder in the wrong place.

 

These would not be a problem if:

You use very little solder

Your solder should be thin, 0.031" max. Thinner if available. Rosin core for sure.

The iron tip needs to be very clean and freshly tinned. Cleaning for every joint is not excessive.

The board is very clean. IPA wipe-down if pre-tinned is fine, but may need a steel wool scrub if bare copper. Get every splinter out of you do use wool.

A small bit of flux may be necessary, but generally that in the solder itself is sufficient.

Thanks, I can see a few points where I may have gone wrong then.

I am using 0.045" rosin core solder which seems too large in that case. Also, I did clean and tin the tip but, I only cleaned after every 5 or so joints. As for the board it is pre-tinned, fresh from the PCB fab, but I should have wiped it down with IPA first. It was vacuum packed on delivery so I trusted it was clean.

Through hole parts are best soldered with a soldering iron.

The picture is blurry, but I think better technique would yield better results. Heat the lead and pad and apply only enough solder to get sufficient wetting.

If solder is going "up" the leads, you're applying solder in the wrong place.

Thanks for your reply and I appreciate the picture is not very good, but its the best camera I have sadly whilst my phone is in for repair.

I did heat the lead and pad, but to be honest I feel like maybe I need to use a wider tip for better heating of the pad. I used a very fine tip and had to use the side of the tip, but perhaps a larger tip would help here. I think I should experiment with the tips I have to see which is most suitable.

As for the solder going up the leads, due to the diameter of the solder and the pitch spacing I found it hard to get the solder into the correct place without accidentally touching the pins higher up. Also at times when removing the iron I accidentally moved upwards instead of sideways so I have taken this into consideration.

I will take yours and ErnieM's advice into consideration and try and give it another go. I just wondered whether there was a better and less error prone method for soldering these.

 

I used a very fine tip and had to use the side of the tip, but perhaps a larger tip would help here.

I use a 700F conical tip for virtually all of my soldering.

As for the solder going up the leads, due to the diameter of the solder and the pitch spacing I found it hard to get the solder into the correct place without accidentally touching the pins higher up. Also at times when removing the iron I accidentally moved upwards instead of sideways so I have taken this into consideration.

Apply the soldering iron to the pad and lead from the outside edge. Extend the solder wire through the leads on the other side to the lead and pad opposite of the iron. When you have sufficient solder, remove the solder wire, then the iron.

If you're not ambidextrous, rotate the work 180 degrees to do the other row of pins.

When you remove the iron, move it away from the point where you applied the solder; it shouldn't touch anything as you remove it and it shouldn't have excessive solder on it anyway.