Pedal mod soldering frustration

I'm trying to do a cap change to my Joyo Vintage Drive. I unsoldered the original cap and used braid to remove the old solder. No matter what I try 60/40 will not flow into the joint. I'm using a hot iron. The pads haven't lifted but they do look blackened. Any ideas??

Are you putting the metal pieces through holes in a board and soldering from the back side? Solder will travel towards the heat.

I did try applying the solder on the opposite side of the board from the iron but it just globbed up on the lead and refused to go in. The board was originally wave soldered and I'm using 60/40 but there doesn't seem to be any solder in there. I rolled up soldering braid and stuck it in the hole to try to get every last bit out.

You need to apply the heat to the cap side and run the solder from the opposite side. If the iron is hot enough, the solder will wick towards the heat, and should only take a quick second, or you'll get things to hot.

1. Apply flux to the pads - you might have some oxidation (dirt) left from desoldering
2. Ensure that your tip is very clean before applying solder

Just a couple of things that come to mind.. (mistakes I have made before!)

Good luck

I guess I need to get some flux. Tried again with a 480 degree iron and the solder's just not sticking to the pad.

I guess I need to get some flux. Tried again with a 480 degree iron and the solder's just not sticking to the pad.

Since you said "480 degree iron" I'm assuming you're using a temperature controlled iron. That temperature is too low. I usually have mine set around 700 degrees. Get in fast, solder, then out.

You also need to make sure your iron is actually touching the pad. I'm used to soldering larger connections such as those on amps and radios. When I started building pedals, I found soldering PC boards is a bit trickier (for me anyway) since the pads and leads are so small.

-Kevin

Since you said "480 degree iron" I'm assuming you're using a temperature controlled iron. That temperature is too low. I usually have mine set around 700 degrees. Get in fast, solder, then out. -Kevin

I keep my iron about 700 as well. Also make sure the components are getting heated, not just the solder. If you do it properly the solder should flow to the heat. If the components aren't heated and you melt the solder you will get a blob.

Place the soldering iron on the pad, move it until it touches the component lead, and then apply solder to the junction opposite the iron.

Also, never solder both sides of the board. If the solder doesn't wick all the way up the plated barrel, it is no big deal (especially when soldering those pesky ground leads). The standard for this type of electronics (Class I) is 50% fill.