"Because HE Isn't R2-D2"
The unconventional color scheme of R2-D3 has always caused a bit of confusion. Die-hard Star Wars fans can tell you what his name is and can pinpoint what movie he appeared in. To make things more interesting, this droid is sometimes referred to as R2-C4. In the end, I usually explain that he is a "background droid" from Episode 1 and that seems to clear things up, for the most part.
It was 2006 when I began construction on my first R2-D3. In spring of the following year, I completed him and hauled him from Tulsa to Los Angeles for CIV. This was his first public appearance. A few years later I shipped him to Orlando for CV which was an event I really enjoyed, especially since I didn't have to drive the droid in myself.
One of the things I learned along the way is that droid weight is an issue for me. This all metal droid clocked in at roughly 200 pounds, which is not uncommon.
So I began to think about building a lighter droid.