I was largely a VBA / SQL developer at the time, so it wasn't something I'd encountered before. Even now, as a VB .Net developer, I know what the point of StringBuilder is but could only name the .Append() and .AppendLine() functions off the top of my head.
The point of my post, as I believe you may have missed, wasn't just to "copy and paste" but to understand as well. You're a lucky man if you can find a piece of code online that does exactly what you want. whatever code you find will need changing in some way, or implementing as part of a greater bit of code. Understanding the code is essential to that.
And incidentally, yes. I did take that as a cue. I spent a short half hour or so that evening reading up on Stringbuilder. Via Google.
Biting the hand that feeds IT
