BillFitzmaurice.info

Buy a cheap cap at RS and cut off the lead to use for your wire.

Use a stainless sewing needle or dressmaker's needle to open the hole in the board.
Once you have it opened, you can insert your lead wire.

A soldering gun is definitely not the right tool for this job.
You need 450C tip temp to get in and out quickly.

bgavin wrote:
A soldering gun is definitely not the right tool for this job.
You need 450C tip temp to get in and out quickly.

I use a soldering gun, but one that's at least 75 watts. Typical 25-30 watters won't heat a joint quickly enough, you have to leave it in place so long that heat spreads into the component causing damage. A 75 watter will heat the joint in a second or two so you can apply the solder and get the iron off the joint lickity-split.