[Toolmaster]

I have a 18 inch bartop to install on a 2*4 wall. Just regular formica with an overhang, the tops come with a 3/4 inch lip around them, so I was going to cut a piece of 3/4 ply the shape of the under side of the top, and then screw it down to the 2*4 place the top on and screw the ply to the top from underneath. Now the question is with the 15 inches hanging over what would be the best looking and strong enough way to hold up the overhang. Thought about just putting some crown under there.

 

[Ron6519]

You'll need a lot more then crown molding to keep it up. It should have at least a 6"-8" support under it to keep it from collapsing under inordinate weight. Like your son sitting on the edge.
Ron

 

[cabinetman]

You'll need a lot more then crown molding to keep it up. It should have at least a 6"-8" support under it to keep it from collapsing under inordiate weight. Like your son sitting on the edge.
Ron

Absolutely. What's needed works like a gusset. They can be made easily, or purchased. They may be called "brackets" or "corbels".