Used steel that was just sitting around, doing nothing. I had a few chunks. was around 3/16" thick,, 18" X 48". So the extension added 18 inches out front and 18" high on the sides. Reinforced with 1 X 1" angle iron. Weighs less then 75 pounds (in guessing) so I can manuver it alone. I have two 4" wide skids on the botton to keep it off the gravel.
I'm not real good at welding, I can make it stick real good, but don't look too close at the bead. (Whadda ya want for nuttin????)
I don't think I would have made it any longer, since my dump height is now limited.
Helps alot since I have one area in the driveway that drifts badly. Can get 3 or 4 feet deep. Taking bigger bites make it much easier.
Works well for mulch too.